Codling moth life cycle

Found in all apple-growing areas of the world, the codling moth (Cydia pomonella) is considered to be one of the most destructive pests of apples. Adults are gray to brown moths with a 3/4 inch wingspan. They have a chocolate-colored patch at the tip of each forewing and coppery transverse markings.

Codling moth larvae are pink or creamy white caterpillars with mottled brown heads that tunnel through apples directly to the core. As they feed, they push out mounds of fecal material, called frass, which gathers around the entrance hole. Damage lowers the market value of the fruit and makes it unfit for human consumption. Alternate host plants include pears, crabapples, walnuts and stone fruits.

Note: The codling moth was introduced to North America by the colonists more than 200 years ago and is now one of the leading pests in home orchards.

Contents

Life Cycle

Full grown larvae pass through the winter in a cocoon beneath loose bark or in orchard litter. Pupation takes place in the spring. Moths begin emerging about the time that apple trees are in bloom and lay an average of 50 to 60 eggs on leaves, twigs and fruits. Once eggs hatch the larvae feed briefly on leaves, then damage fruit by boring into the centers. Larvae feed for three weeks, then leave to seek a suitable place to spin cocoons. There are two generations per year.

How to Control

  1. Scrape loose bark in early spring to remove overwintering cocoons and then spray All Seasons® horticultural oil to eradicate eggs and first generation early instar stages.
  2. Beneficial nematodes are microscopic, worm-like parasites that actively hunt, penetrate and destroy immature stages of this pest. Spray on trunks and main branches, and also over the soil out to the drip line for a 60% to 90% mortality in pre-pupae.
  3. Use pheromone traps to determine the peak flight period for moths, then release trichogramma wasps to attack eggs. Pheromone traps will also help reduce male moths where populations are low and trees are isolated.
  4. Bt-kurstaki (Bt) and Spinosad sprays are moderately effective since the larvae spend so little time feeding outside the fruit. Apply during egg hatching only (consult with a local extension agent for exact times).
  5. Surround WP — a wettable kaolin clay — can be used to deter a broad range of fruit tree pests (and diseases), and will reduce codling moth damage by 50-60%. Apply before moths arrive and continue for 6-8 weekly applications, or until the infestation is over.
  6. In areas of severe infestation, spray plant-derived insecticides when 75% of petals have fallen, followed by three sprays at 1-2 week intervals. These natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.

Tip: In spring, band tree trunks tightly with corrugated cardboard strips (4- to 6-inches wide) to provide a site for larvae to spin their cocoons. Remove and destroy the strips after cocoons are formed.

Codling Moth Protection – Tips For Controlling Codling Moths

and Becca Badgett
(Co-author of How to Grow an EMERGENCY Garden)

Codling moths are common pests of apples and pears, but may also attack crabapples, walnuts, quince and some other fruits. These small unassuming moths are dangerous to commercial crops and can cause extensive fruit damage. Actually, it is the moth’s progeny, the larva, which cause the damage while feeding.

Controlling codling moths is important to prevent the spread of the insects and widespread orchard damage. Fruit trees need to be treated according to the codling moth life cycle to be the most effective. Then you need to find out what kills codling moths and which method is best for your gardening style.

About Codling Moths

The small brown to tan moths overwinter as larva in cracks of bark or other hidden areas. They pupate in spring and emerge winged shortly after. The moths lay eggs within three days of emergence which are tiny and nearly transparent. These hatch in 8 to 14 days. The newly hatched larvae must feed to grow and begin development towards cocooning stage.

The larva enters the fruit, chewing as they proceed to the core. After digesting the fruit, it is released as frass (excrement) that spills from the entrance hole, making the fruit highly undesirable. They feed on the fruit until they reach full growth, which is ½ inch long, white with a brown head and a pink tinge at the end. The codling moth life cycle starts anew when these fat larvae attach themselves to a surface and cocoon for winter. Codling moth control is needed to eliminate this unpleasant scenario.

How to Treat Codling Moth

You need to know if you have the pests before you figure out how to treat codling moth infestations. Codling moth traps, containing pheromones (sexual hormones), that attract the codling moth can be used to determine the location where codling moth control is needed. Set these out when the tree is just blooming. If you find the moths in the trap, you will need to spray the trees or use mechanical or biological controls to prevent fruit damage.

Controlling coddling moths is done through a variety of ways. One primary form of codling moth protection on fruit trees is to avoid the use of broad spectrum pesticides. These kill beneficial insects, such as some wasps, which eat the larvae. Birds are important predators of this insect and an important means of codling moth control. Make your garden bird friendly and invite your feathered friends to feast on the codling moth youngsters.

What Kills Codling Moths?

Let’s start with the obvious. Mechanical removal is one of the safest and simplest methods, but it only works if your tree is easy to access. Large plants would require you to crawl over them on a ladder and that is just not practical.

Pre-season coddling moth protection can be achieved to some degree by removing and picking up old fruits from the ground. This removes some of the larvae and prevents them from reaching adulthood and starting the codling moth life cycle all over again.

Some natural things to try are spinosad, granulosis virus and Bacillus thuringiensis. Carabyl is a very effective pesticide, but it can also affect honeybee populations.

Controlling Codling Moths on Fruit

There are topical applications that can prevent codling moth larvae from feeding on fruit. Bags, or even nylons, slipped over developing fruit can prevent larvae from accessing and eating them.

You may also put a cardboard shield around the trunk of the tree to keep larvae from climbing up to the fruit. Larvae can’t fly or swing themselves from tree to tree, so this is actually a very practical and useful method.

Whichever way you decide to control the pests, the first offense is monitoring their existence and charting their life cycle.

Codling Moth

University of Kentucky College of Agriculture

The codling moth larva is one of the very destructive pests introduced from Europe by settlers. This is the ‘worm in the apple.’ While it can attack various fruits, it primarily damages apples. This is a key pest of apples that requires management in every orchard in Kentucky.

Identification and Biology

Female moths lay individual scale‑like eggs on developing fruit or adjacent leaves or stems at night. Upon hatching the larva enters into the calyx end or side of the fruit then tunnel to the center where they feed and develop. Brown frass is often noticed near the calyx end of the developing fruit. The larva is pinkish to white in color with a brown head and can reach 3/4 inch. Larval development is completed in 3 to 5 weeks. Larvae exit the fruit to pupate in a thick silken cocoon on the bark or other protected areas. The fully developed larva is the overwintering stage. Pupation occurs in spring beginning about the same time as bloom with adults emerging in late April or early May. In Kentucky, there are three generations each year. The adult is about 3/8 inch, gray, with distinctive bronze areas on the bottom 1/3 of the wing.

Figure 1. Adult codling moth showing characteristic coloration of tip of wings.

Control of codling moth in commercial orchards relies on three tools: regular scouting of the trees and fruit, pheromone trapping, and the use of weather monitoring and degree day models. Orchards should be scouted twice a week early in the season and on a weekly basis for insects and mites during mid‑season. Closer to harvest scouting visits may be stretched to two weeks apart.

Pheromone Trapping

Pheromone trapping uses chemical lures to attract male moths. These chemical lures are synthetic copies of the chemicals female moths use to attract males for mating. A trap consists of plastic top and bottom held together by a wire hanger with the lure placed inside. The inner surface of the bottom is coated with a sticky material to hold the insects once they land in the trap. Traps are hung in the southeast quadrant of the tree at eye level, usually one for each ten acres of trees (minimum of two traps per orchard) in commercial orchards.

Figure 2. Codling moth larva feeding in the apple core.

Homeowners can use pheromone traps to time insecticide sprays by identifying when peak flight periods are occurring. See the section on degree days to time applications following peak flights. Some homeowners have attempted to “trap out” all the male moths. This involves using enough pheromone traps such that all of the male moths are captured before the female moths mate. Female moths are then able to lay only unfertilized eggs that will not develop. Typically, 2 to 4 traps per tree are required for this to be successful. This is less effective if there are additional sources of mated females, such as other trees in the neighborhood or wild hosts. Pheromone traps should be put out at the pink stage of bud development. Every month, pheromone lures need to be replaced. Codling moths can be distinguished from other insects in the traps by their bronze wing tips. Pheromone trap suppliers can be found by searching the internet.

Degree Day Accumulation

Initial trap catches for adult moth in the early spring are termed biofixes. This information will be used to predict when egg hatch will occur and synchronize insecticide sprays. The biofix for the codling moth is the starting date of the first sustained flight of male moths captured in pheromone traps. Generally, this is when the fifth moth has been captured in the trap. A few moths often emerge very early in the spring ahead of the rest. Using the fifth moth as the biofix better represents when the majority of the codling moths begin to emerge. This usually occurs just after petal fall. Codling moth traps need to be examined daily in order to know exactly when the biofix occurs. After the biofix has occurred, degree days are calculated on a daily basis and a running total is kept (see “Predicting Insect Development Using Degree Days” in ENTFACT 201). The codling moth has a 50°F threshold temperature. The UK Ag Weather Center has a codling moth degree day model that provides these values based on the temperatures in your county, users just need to enter the date of biofix.

Throughout the growing season in commercial IPM orchards, pheromone trap catches that exceed an average of five moths per trap per week can tripper an insecticide application. Growers need to estimate the residual activity of previous insecticide sprays (generally 10 to 14 days of activity after each application) relative to the anticipated egg hatch predicted by the degree day accumulation to determine the need for additional sprays.

Trunk Banding

Another tactic that can be used by home owners is the use of cardboard bands placed around the trunk of the trees to serve as pupation sites for the wandering larvae. A four to six inch band encircling the trunk or scaffold limbs will attract the larvae. Bands should be in place before larvae begin to leave the apples in search of pupation sites and removed and destroyed before moth emergence begins. Bands should be placed on trees in August to capture overwintering pupae and removed and destroyed in December. Bands can also be used in the summer to capture pupae from the summer generations, but timing is more difficult.

Sanitation

Home owners should also pick up and destroy fallen fruit. Often fruit that drop prematurely are infested with either codling moth or plum curculio larvae. For more information on reduced insecticide apple management, see ENTFACT‑201, Apple Insect Control with Reduced Insecticide Usage.

Pesticide Resistance

Codling moth resistance to some of the older insecticides that had been used for control. Fortunately, there are new labeled insecticide alternatives for codling moth control on apples with different modes of action. Growers should not rely on a single insecticide mode of action throughout the year to control codling moth. I recommend switching to a different mode of action with each new generation during the year.

Mating Disruption

Mating disruption relies on confusion to prevent codling moths from mating. Male codling moths locate female moths at night by following the sex attractant released into the air by the females. Mating disruption uses commercial dispensers of synthetic sex attractant to prevent male moths from locating females. Unfertilized moths are not able to lay viable eggs. Unlike other methods, codling moths are not killed with this technique. This technique is most successful in blocks of at least 5 acres and where initial populations of codling moth are low. Keep in mind that mating disruption for codling moth will not control other insects that are normally controlled with cover sprays (plum curculio or Oriental fruit moth for example).

Revised: 2/10

CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.

Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!

Photos courtesy Ric Bessin, University of Kentucky Entomology

Apple-Codling moth

Cydia pomonella

Pest description and crop damage This is the most serious pest of apples in the PNW, especially in warmer, dryer areas. Adult moths are 0.5 inch wide, with alternating gray and white bands on the wings and a copper band on the wing tips. Larvae are whitish with a black head when immature, and pinkish with brown heads when mature. Larvae are 0.1 inch long at hatch and 0.8 inch long at maturity. Pupae are brown and about 0.75 inch long. The eggs are very tiny and rarely seen.

Larvae feed directly on the fruit, boring into it and feeding within. Stings are shallow depressions where feeding occurred and stopped. Larvae bore into the fruit, leaving a characteristic tunnel filled with frass that extrudes from the hole on the fruit surface. Entry holes may be anywhere on the fruit.

Biology and life history Codling moth overwinters as mature larvae in silken cocoons (hybernaculi) spun under loose bark, in the soil, or in litter at the base of the tree. Pupation takes place in the spring around the time the first blossoms are showing pink, and adults emerge around bloom. Adults are active only at dusk and dawn and lay eggs on leaves, or occasionally on fruit.

The larvae emerge, begin feeding on fruit, and may bore to the center of developing fruit to feed on the flesh and seeds. As they mature, they push frass out of the entry hole. After 3 to 4 weeks, the larvae leave the fruit to seek a sheltered spot on the tree to spin cocoons.

The larvae may overwinter in the cocoon, or they may emerge in 2 to 3 weeks as a new flight of adults. These adults are active in July and August. In warm areas, there may even be a third generation. Larvae of this brood often penetrate fruit but do not complete development before harvest or the onset of winter.

Sampling and thresholds The development of codling moth can be predicted by the accumulation of heat units, or degree-days using phenology models. By knowing the stage of the insect, we can target management to specific life stages that are susceptible. For codling moth, that means that our treatments are targeting the eggs or the wandering larvae during the brief period between egg hatch and the time when the larva is able to penetrate the fruit where it is protected. Phenology model recommendations can originate with your local Extension resource, crop consultant, software system, or use of an online degree-day calculator. It is important to make sure that you are using an appropriate tool/model for your region. Homeowners can also benefit from use of degree-day models to predict management timing.

To calculate biofix for degree-day modeling hang traps with 1 mg pheromone lures in the upper canopy at pink. Biofix is the first capture of multiple male moths in a trap or consistent capture of multiple males over more than one trap. The biofix date is used as the point to start accumulating degree-days for the Stanley and Hoyt (1987) degree-day model, which is still the best model for PNW locations south of 46°N. North of this latitude, the no-biofix model can be used (Jones et al. 2008). The CM-DA lure contains a food odor and will catch females as well as males. Capture of females indicates potential for eggs and damage but models use male captures for setting biofix.

When mating disruption is used, monitor the orchard with pheromone traps baited with 1 mg pheromone or CM-DA lures set in the upper third of the canopy. If more than five male moths are captured in a trap over the first generation, check the orchard for fruit damage or apply a conventional insecticide. If fruit damage exceeds 0.5% at the end of the first generation, use conventional insecticides to provide supplemental control against the second generation. If more than two male moths are captured in a trap during the second generation, a conventional insecticide may be necessary.

Management-cultural control

In small orchards, sanitation by removing and disposing of young damaged fruit can be helpful in reducing codling moth. Check regularly throughout the season for fruit with frass-filled holes. Removing and destroying infected fruit prior to larvae emergence preceeding pupation can help reduce overall populations. Picking up dropped fruit from the ground likewise can be an effective sanitation measure. Homeowners can bag individual fruit (clusters thinned to one fruit) in paper bags approximately six weeks after bloom, however this can be labor-intensive and more challenging for cultivars with short stems. Fruit will mature completely within bags, however color development on red varieties may be affected. Homeowners can also place corrugated bands of cardboard around the lower trunk to attract larvae looking for a place to pupate. Place in May and remove before the adults begin to emerge in mid-June. The same technique can be used with the subsequent generation(s) later in summer.

Management-chemical control: HOME USE

After petal fall spray and spring and summer sprays

Apply first cover spray at 250 degree-days after biofix, or about 10 days after full petal fall (all petals are off) or 17 to 21 days after full bloom. Insecticides must be timed to target newly hatched larvae before they bore into the fruit. Multiple sprays are often necessary with applications up to every 10-14 days, however sprays can be reduced by monitoring for adult moths with monitoring traps or use of degree-day models (see description above) to properly time insecticide applications to the hatching larvae during the growing season.

  • acetamiprid
  • azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
  • carbaryl
  • esfenvalerate
  • gamma-cyhalothrin
  • insecticidal soap-Some formulations OMRI-listed for organic use.
  • kaolin-Applied as a spray to leaves, stems, and fruit, it acts as a repellant to pests.
  • lambda-cyhalothrin
  • malathion
  • mating disruption pheromones-See biorational control above. Not effective for orchards less than 10 acres.
  • permethrin
  • pyrethrins (often as a mix with other ingredients)
  • spinosad
  • zeta-cypermethrin

Management-biorational control: COMMERCIAL USE ONLY

Stages 5-6: Pink application

Mating disruption. Pheromone release devices placed in the orchard interfere with the communication from female to male codling moth and this prevents or delays mating of moths, reducing the number of eggs laid and crop damage. A number of hand-applied pheromone dispensers are available including Isomate C+, Isomate CTT, NoMate, CheckMate, Cidetrak CM, and Checkmate CM-XL 1000. These dispensers are typically applied to trees at densities of 200 to 400 per acre, sometimes with a higher density of dispensers applied to orchard borders. Aerosol devices (also called puffers) for releasing pheromones are increasingly favored for their efficacy and ease of application at densities such as 1 device/a. Substantial fruit damage could result from improper use of mating disruption, therefore follow the label recommendations. Blocks placed under mating disruption should be large, ideally greater than 10 acres, and prospects for success increase when neighboring orchards are also using the tactic and the codling moth pressure is low. Pheromone dispensers can be applied to dormant trees and must be in place before first moth flight around the time of full bloom of Red Delicious. Place within 2 ft of the top of the canopy. If the orchard has a history of codling moth problems, use one or more insecticide applications against the first generation. If a codling moth source exists nearby, use border sprays (five to six rows) of insecticides.

Management-biological (microbial) control: COMMERCIAL USE ONLY

  • codling moth granulosis virus (Carpovirusine, Cyd-X, Virosoft CP4)-Check label for rates. REI/PHI 12 hr. Granulosis virus is a selective biological insecticide that must be ingested to be effective. Thorough coverage is important. The virus degrades when exposed to UV light. If a grower relies only on granulosis virus for codling moth control, frequent applications are necessary (every 7 to 10 days), especially when codling moth pressure is high. The virus controls larvae, but some fruit damage, primarily stings, may be evident. OMRI-listed for organic use.

Management-chemical control: COMMERCIAL USE

After petal fall spray

Apply first cover spray at 250 degree-days after biofix, or earlier for ovicidal materials. This roughly corresponds to about 10 days after full petal fall (all petals are off) or 17 to 21 days after full bloom for ‘Red Delicious’. A second treatment is recommended approximately 14 days after the first (depending on residual) to cover the full period of moth egg laying in the first generation. The first summer generation spray should be applied at 1250 degree-days after biofix, and again a second treatment in 14 days will help cover the entire egg hatch period. Materials with rapid breakdown such as codling moth granulosis virus should be applied on a more frequent schedule.

  • chlorantraniliprole (Altacor) at 3.0 to 4.5 oz/a in no less than 100 gal water per application. Do not apply more than 9 oz/a per growing season. Do not use an adjuvant within 60 days of harvest. REI 4 hr. PHI 5 days.
  • methoxyfenozide (Intrepid 2F) at 16 fl oz/a in up 100 gal water per application. For use against low- to moderate-pressure situations, with alternate control measures such as mating disruption. Use adjuvant; see label. Do not exceed 64 oz/a per growing season. REI 4 hr. PHI 14 days.
  • novaluron (Rimon 0.83EC) at 30 to 50 fl oz/a in up to 100 gal water per application with a second application 14 to 17 days later. Do not apply more than 150 fl oz per growing season. REI 12 hr. PHI 14 days.
  • pyriproxyfen (Esteem 35WP) at 4 to 5 oz/a in up to 100 gal water per application. Do not exceed two applications per season. Do not apply earlier than 14 days after last Esteem 35 WP treatment. REI 12 hr. PHI 45 days.

Spring and summer

  • acetamiprid (Assail 70WP) at 1.7 to 3.4 oz/a in up to 100 gal water per application. Do not make more than 4 applications per year or exceed 13.5 oz/a per growing season. Adding a low rate of horticultural mineral oil improves effectiveness against codling moth. REI 12 hr. PHI 7 days.
  • Chromobacterium subtsugae (Grandevo) at 1 to 3 lb/a. Under heavy pest populations, apply a knockdown insecticide prior to or in a tank mix, use the higher label rates, shorten the spray interval, and/or increase the spray volume to improve coverage. REI/PHI 12 hr. OMRI-listed for organic use.
  • clothianidin (Belay 50WDG) at 3.2 to 6.4 oz/a. For control of first generation codling moth in areas with light pressure and suppression of first generation codling moth in areas of heavy infestation. Do not apply more than 6.4 oz of Belay per acre per season. REI 12 hr. PHI 7 days. Do not feed or allow livestock to graze on cover crops from treated orchards. Belay must not be applied during bloom or if bees are actively foraging. .
  • chlorantraniliprole (Altacor) at 3.0 to 4.5 oz product/a in no less than 100 gal water per application. Do not apply more than 9 oz per acre per growing season. Do not use an adjuvant within 60 days of harvest. REI 4 hr. PHI 5 days.
  • emamectin benzoate (Proclaim 5SG) at 3.2 to 4.8 oz/a in up to 100 gal water per application. For use in low to moderate pressure situations with alternate control measures such as mating disruption. Do not exceed 14.4 oz/a per season. REI 12 hr. PHI 14 days.
  • fenpropathrin (Danitol 2.4 EC) at 16 to 21.3 fl oz/a in up to 100 gal water per application. Will also reduce mite populations but may cause resurgence the same season. Do not exceed 42.7 fl oz per acre per season. REI 24 hr. PHI 14 days.
  • flubendiamide (Belt SC) at 5.0 fl oz/a in a minimum of 100 gal water per application. Do not exceed three applications per growing season. REI 12 hr. PHI 14 days.
  • granulovirus virus M (CpV-M) (Carpovirusine) at 6.8 to 13.5 fl oz/a in 100 gal water per application. Start at the beginning of first generation egg hatch. Apply every 7 to 10 days. REI/PHI 12 hr. OMRI-listed for organic use.
  • indoxacarb (Avaunt) at 5 to 6 oz/a in up to 200 gal water per application. Make no more than 3 applications prior to hand-thinning. No hand thinning after the 4th application. Make no more than 4 applications per growing season. Do not apply more than 24 oz/a per growing season. For use in low- to moderate-pressure situations, with alternate control measures such as mating disruption. REI 12 hr. PHI 14 days.
  • methoxyfenozide (Intrepid 2F) at 16 fl oz/a in up to 100 gal water per application. For use against low- to moderate-pressure situations, with alternate control measures such as mating disruption. Do not exceed 64 oz/a per season. REI 4 hr. PHI 14 days.
  • novaluron (Rimon 0.83EC) at 30 to 50 fl oz/a in up to 100 gal water per application. See label for application timing. Do not exceed 150 fl oz/a per season. REI 12 hr. PHI 14 days.
  • phosmet (Imidan 70W) at 2.1 to 5.7 lb/a in up to 100 gal water per application. REI/PHI 7 days.
  • pyriproxyfen (Esteem 35WP) at 4 to 5 oz/a in up to 100 gal water per application. Do not exceed two applications per growing season. REI 12 hr. PHI 45 days.
  • spinetoram (Delegate WG) at 6 to 7 oz/a in up to 100 gal water per application. Do not exceed four applications per season. REI 4 hr. PHI 7 days.
  • spinosad (Entrust 80WP) at 2 to 3 oz /a in up to 100 gal water per application. Do not exceed 9 oz/a per season. REI 4 hr. PHI 7 days. OMRI-listed for organic use. larvicidal]
  • thiacloprid (Calypso 4F) at 4 to 8 fl oz/a in up to 100 gal water per application. Do not exceed 16 fl oz/a per season. REI 12 hr. PHI 30 days.
  • thiamethoxam/chlorantraniliprole (Voliam Flexi) at 4 to 7 oz/a in up to 100 gal water per application. Do not apply exceed 16 oz/a per season and do not use an adjuvant within 60 days of harvest. REI 12 hr. PHI 35 days.

CODLING MOTH BIOLOGY ^

Codling moth larvae will naturally be attracted to apples when they hatch

Codling moths have accounted for more damage to apples then any other pest. Their unique biology combined with their physical attributes makes them forever a formidable foe to anyone that grows apples. Whether you have 1 tree or an orchard spanning hundreds of acres, codling moths can take away your harvest quickly and consistently. This article will detail their biology and then offer practical and viable treatment schedules which will help keep your apples in tip top shape and not worm food!

Codling moth adults don’t cause apple damage directly. In fact, like many other insects, it’s their larva which do all the bad deeds.

Codling moths overwinter in the pupa stage and emerge in the spring when local temperatures are right. This is a key time for controlling the emerging adults and every region has a different time of the year when such activity happens. Getting an early grip on their development can prove to be a big help when the local environment has a large population.

Since codling moths are present in all parts of the world, there is no single time or date when everything starts. Since their young feed primarily on apples, the adults will emerge at a time when food will be ready for when their offspring need it. At this time, males will be seeking females. Once mated, females will begin to lay eggs. If this occurs early in the season, she will lay her eggs on the branches and the bark of local apple trees. The first egg laying will yield small amounts of eggs and sometimes only one at a time will be laid. As the temperatures warm, so too will her egg yield. Though these females will only live about one month, they will lay 50-100 eggs during this time.

CODLING MOTH LIFE CYCLE

Codling moth (Carpocapsa pomonella). Woodcut engraving after a drawing by Emil Schmidt (German painter, 19th century), published in 1882.

The eggs will develop and start to hatch in 2-4 weeks. This will again depend largely on local temperatures. A colder spring will tend to keep them dormant longer; warm weather will get them going all the more faster.

Once hatched, larva or “apple worms” will forage for fruit on which to feed. It is not uncommon for one apple to have several larva inside. It is also not uncommon for a larva worm to enter an apple and then die. This promotes rot and discolors fruit making it look bad and rotten.

Codling moth larvae eating apple

Once inside, larva will feed and grow through 4-5 instars or stages of development. Once completing their stages, larva will leave the fruit and seek a good place to pupate. In the southern zone of the United States, this cycle will play out over the course of the growing season. Eggs will hatch larva worms which will feed on apples; once they have gone through their growth they will leave the apple to spin a cocoon in which to change to an adult and then emerge to mate and reproduce. This could happen several times a year if conditions are right. However, it is most common to have two cycles occur in any one year and sometimes three. For this reason it is important to get the moth stage before they are able to lay eggs. Since larva cannot move great distances, if egg laying is minimized so too will larva damage. This essentially means that if you are able to stop all moths from laying eggs on any one tree or fruit, no damage would happen to it. Though this sounds easy and sound, the reality of achieving success is complicated. For this reason it is important to employ different strategies for different times of the year.

CODLING MOTH TRAPS

As explained above, interrupting the mating process is key to preventing the codling life cycle from getting established on your land. If you can prevent females from mating with males, you will effectively reduce the amount of egg laying which occurs on the tree.

Yes it is true that moths can come from other areas and find your tree but this is not too likely. Since most pupa hatch close to where they fed as larva they will be attracted to the same trees that have provided food for all generations before them. Furthermore, codling moths don’t fly all too well. They are not designed to travel great distances and though they can move from one tree to another in any one orchard, once they leave that common ground they are pretty much lost. For this reason, it is safe to say that any one tree or stand of trees has a certain amount of “seed” pupa which will hatch in any one spring. Clearly impacting this first hatching can have a dramatic impact on just how many or just how few codling moths are able to develop over the course of the year.

For this reason it is imperative that you get up some CODLING MOTH TRAPS before over wintering pupa hatch. Yes, it may still be cold out, but if you want to protect your crop, it’s better to be safe then sorry. Just remember the old adage about “the early bird gets the worm”. Well, your taste in worms might not be a codling moth worm but getting them before they get your apples is what any grower would prefer!

Pheromones will remain active for 30 -60 days and each tree you’d like to protect should have a trap. Keep in mind using traps is not a method of control; traps are designed to keep you “updated” as to what is happening out in your orchard. So if you have 5-10 traps set up in one acre and don’t catch a moth, you’re in good shape. But if you have one tree and one trap and catch several moths, you have a problem requiring immediate attention.

Timely placement of Codling Moth traps will assuredly cut down on the amount of egg laying which can occur. However, it is not likely that traps alone will serve to collect and kill every moth around any one or group of apple trees. If you only have one tree to protect, this same program will apply.

Remember, traps can catch a lot of males which will not be able to mate allow for egg laying females. However, some will inevitably mate and eggs are sure to find their way onto a tree or two if you have activity. To deal with this, there are varying treatments listed below. Choose a method with which you feel comfortable and one that will allow you to achieve your goal. This is largely an individual choice since apples to some are the gardens finest yield and to others are nothing but deer food.

CODLING MOTH SPRAY

If your traps are catching codling moths and you need to spray your trees for protection, there are several options depending on your goal.

ORGANIC CODLING MOTH SPRAY

For the organic gardener, MULTIPURPOSE INSECT KILLER is strong enough to handle codling moths yet safe enough to use on fruits like apples one day to harvest. Treatments will kill both adults and foraging larvae. In general, as soon as you detect or suspect adults are active in your region, treating trees every month will ensure they’re protected.

Mix 6.4 oz to one gallon of water and spray all foliage, limbs and trunk surfaces you can reach. One quart of concentrate is enough to make 5 gallons of product and will treat up to 2500 sq/ft. Gallons will cover up to 10,000 sq/ft.

Remember, Multipurpose Insect Killer is strong enough to manage codling moths. But since its organic, you won’t get any lasting residual so if you want or need something stronger, consider one of the concentrates listed below.

READY TO SPRAY CONCENTRATE

The next step up from the organic option is CYONARA RTS. It comes packed in a hose end sprayer so all you have to do is hook it to your garden hose and start spraying. It’s odorless, labeled for use on garden vegetables and fruit and is very effective against codling moths. Quarts go a long way too (almost 1/2 acre of coverage per quart).

More important, treatments last providing residual for several weeks. This helps by killing moths or larvae which come to the trees after you spray but since the treatment is detectable by insects in general, Cyonara will also repel insects elsewhere.

For large scale treatments, consider a true concentrate. These will require spraying equipment but will cover large areas and for anyone treating orchards, a better option.

BEST CODLING MOTH SPRAY

If you’re looking for a true concentrate to mix with water to apply with a pump sprayer or mist blower, go with VEGETABLES PLUS PERMETHRIN. This product is labeled for use on fruit and vegetables too and like Cyonara, will provide 1-2 weeks of residual. Treating once a month will generally keep trees protected once the season starts.

Add 1.5 oz per gallon and plan on getting 500 to 1000 sq/ft of coverage per mixed gallon. Vegetables plus has 7 days to harvest so keep that in mind when treating.

Commercial growers looking for a true “crop protection” type concentrate, go with CONCENTRATED PYRETHRIN. Pints contain a 5% active and quarts, 6% active.

Pyrethrin is a naturally occurring insecticide extracted from the chrysanthemum flower. Pyrethrin doesn’t provide residual (similar to the Multi Purpose Insect Killer) but it goes a lot further and it can be used as often as is needed. Use just 1-2 oz per gallon of water and use it at least once a month to keep things under control. But if needed, you can apply it throughout the season in case of a break out.

Which ever liquid treatment you choose (either the Vegetables Plus or the Pyrethrin), plan on adding SPREADER STICKER to add to the tank mix along with the concentrate.

Spreader Sticker will enable the active to “spread” over the leaves and fruit that much better so that you effectively get a spray “dispersal” when the treatments hits targeted surfaces. This is important when treating most plants and apple trees are no different.

Eggs and larva can be hiding in the most obscure places and though they don’t do this intentionally, simply spraying to the point of runoff does not mean you have saturated the plant. Any larva which are on a remote part of the plant during your treatment can escape unless they crawl over some area which was treated. Don’t give them a chance – add Spreader Sticker to get complete coverage.

EQUIPMENT NEEDED TO TREAT FOR CODLING MOTHS

When using any of the products listed above, you have a range of sprayers that can be used. Other than the Cyonara RTS which comes with its own sprayer, the other concentrates will require equipment.

For small jobs, a standard PUMP SPRAYER will work fine. Our sprayer can reach 15-20 feet so if your tree isn’t too tall, it can handle the task.

Another option is a good HOSE END SPRAYER. Our sprayer can handle enough concentrate and water to spray out 20 gallons. Using the power of the your garden hose, they can often times reach higher compared to a pump sprayer.

For even extra height, the TROMBONE SPRAYER can reach 30+ feet. It relies on your power to manually operate it and its totally portable. Use a 1 gallon or 5 gallon pail to mix up chemical you can then take afield. The Trombone sprayer has a long hose you’ll drop in the bucket and then use a “trombone” like pumping action to spray the mixture up and onto the trees.

MIST BLOWERS AND FOGGING MACHINES

Another great way to apply the Vegetables Plus, Multipurpose Insect Killer or Pyrethrin Concentrate is by fogging. This process involves using machines that change the liquid to a mist. The mist will do a much better job of covering all the tree foliage and it will do using less chemical and less time. On average 75% less.

For small jobs, the FM6208 is electrical and features a 1 gallon tank. It can spray out 25-35 feet and can handle 1/2-1 acre of trees comfortably.

If you prefer to “cut the cord”, the HUDSON MIST BLOWER features a gas engine and a 3 gallon tank. It will mist out 30+ feet and is well suited for the orchard care taker managing 1-2 acres of trees.

The SOLO MIST BLOWER is essentially the same type of equipment but is considered the “Cadillac” of mist blowers. Its more comfortable to use and can blow the mist 45+ feet up. And its less noisy.

Either of these mist blowers can handle 1-3 acres comfortably but if you have more than 5 acres to treat, consider one of the thermal foggers listed below.

HOT THERMAL FOGGERS

For large scale operations, a thermal fogger is the preferred machine when you need to manage codling moths. These machines will convert water or oil to a true “ulv” which means you’ll use less chemical and require less time to treat.

The TRAIL BLAZER is a hand held unit that can pump out 2.5 gallons of water based material per hour. Well suited for any orchard, you can drive around the property fogging as you go yet this unit is light enough to carry at just 30 lbs with liquids added to its storage tank.

It also features electric start and the ability to fog both water and oil based mixtures.

Lastly, the truck mounted BLACK HAWK is a 70lb+ monster of a thermal fogger. It features electric start too and can pump up to 18 gallons of mixed solution per hour (oil based). Optional water base “converting” kit is available too.

Use this for the biggest farms where the need to fog is ongoing throughout the growing season. The Black Hawk is a powerhouse and a good fit for any farm, golf course or public park.

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Codling Moth

General Description

Hosts

Apple, crabapple and pear; rarely other fruit trees in B.C.

Damage

Surface ‘stings’ (Fig. 1) or holes in fruit plugged with dark masses of excreta (Fig.2); both types of damage allow fungi and bacteria to enter the fruit and cause fruit rot during storage (Fig. 3).

Identification

Larva – Pinkish-white caterpillar with black or mottled black head; mature larvae 12-20 mm long (Fig. 4).

Figure 4. Codling moth larva (BCMA)

Adult – Brownish-gray moth about 10-12 mm long with a copper spot on the end of each forewing (Fig. 5).

Figure 5. Adult codling moth. (AA-FC)

Life History

Mature codling moth larvae overwinter in silken cocoons in protected sites on the tree (under loose bark, in cracks and crevices), in the soil or in wooden materials under or beside infested trees (bins, ladders, poles, buildings, large prunings). Larvae pupate in the spring and adults usually begin to emerge in early May and continue emerging until late June (mid-July in cooler areas), depending on temperature. Mating and egg-laying occur when twilight temperatures are above15°C. Females lay eggs on fruit or on leaves near fruit. Larvae usually wander over the fruit surface before cutting through the skin and boring deeply into the fruit. Mature larvae leave the fruit to pupate in protected sites on and off the tree as described above. Second generation moths appear in late July and August. Because weather during July and August is usually favourable for codling moth activity and reproduction, second-generation larvae can cause considerable damage, often close to harvest. If weather is warm during late August or early September a partial third generation may occur in southern districts.

Monitoring

The OKSIR Program places pheromone-baited traps in every pome fruit orchard (1/ha) in the program area (Fig. 6). Capture data for every trap is posted within 24 hours of collection on the OKSIR web site under Trap Data/Orchard Trap Database (http://www.oksir.org/traps.asp).

Figure 6. OKSIR Program pheromone trap. (OKSIR)

The Program also releases sterile codling moths weekly in the same orchards from May to September (see IFP & Organics chapter). Sterile male moths are also attracted to the pheromone traps. To distinguish sterile from wild male moths, crush each captured moth and those that do not leave a pink to red stain are wild moths.

For growers wishing to place more traps in their orchard, obtain a copy of factsheet Codling Moth Sex Pheromone Traps from the BCMA Kelowna office which provides details on installation, placement, maintenance and use of traps, and assists in the interpretation of trap captures. Install the traps in orchards by the pink bud stage and check weekly to record the location and the number of wild male moths captured.

Replace the lures every 4 weeks and change the trap bottoms when the stickiness diminishes.

Each trap will monitor approximately 1 hectare of orchard. Orchards less than 1 hectare or with mixed fruit types or very irregular borders are difficult to monitor with pheromone traps. After a spray is applied, service the traps as usual to provide the information needed for decisions on additional sprays. Continue to monitor trap catches until 2 weeks before harvest.

Timing of the first codling moth spray in the spring can be more accurate if the beginning of egg hatch is predicted using codling moth trap captures and degree-day accumulations. The BCMA (Kelowna) factsheet Predicting Codling Moth Spray Dates with Degree-Days explains how to measure temperatures, determine biofix and calculate degree-days necessary to time the first spray. A maximum-minimum thermometer housed in a well-ventilated shelter is required in order to record minimum and maximum temperatures necessary to calculate degree-days.

Management

Biological Control

Virosoft CP4 Granulovirus – Codling moth larvae must eat the virus before they enter the fruit, so thorough coverage is essential. The efficacy of the virus deteriorates quickly (short residual period). Apply weekly in the late afternoon or on a cloudy day throughout the period when codling moth larvae are emerging from eggs. Because the granulovirus does not kill codling moth larvae as quickly as most chemical sprays, some feeding damage will occur. Store Virosoft in a cool place between uses to reduce degradation of the granulovirus. This product is certified for use in organic production orchards.

Cultural Control

Banding – Cardboard banding works by trapping and removing larvae after they have left the damaged fruit but before they emerge as adults for the next generation. Wrap corrugated cardboard bands around tree trunks and scaffold limbs by mid-June through to the end of July (apply by 555 DD). Any larvae that would otherwise be spinning their cocoons on the trunk or scaffold branches will be captured in the bands. Remove and replace the bands applied for the first generation larvae around mid-July (750 DD) and burn immediately to prevent larvae from completing their development. If applying bands for the second generation, remove and destroy the replacement bands after harvest. In warm years with a 3rd generation, remove the summer bands at regular intervals to prevent development or remove bands at 1350 DD. Banding material is available from chemical suppliers or OKSIR program.

Fruit Removal – It is extremely important that fruit found infested with codling moth is not left on the trees at any time during the growing season. Growers should make sure that infested fruit found while thinning and picking is destroyed, in order to kill any larvae in the fruit; complete crushing of fruit is the best way to kill larvae. Culled fruit should never be dumped in orchards. If infested fruit is placed in soapy water to drown the larvae, do not remove the apple for at least one week.

Sanitation – Remove any non-commercial codling moth host trees; if on surrounding properties or public lands, inform SIR staff. Woodpiles and any wooden structures, such as fruit bins or boxes, tree props, or ladders, are important sources of overwintered codling moths. As codling moth populations decrease, it becomes important to eliminate or treat wooden structures within or immediately adjacent to the orchards. Pay attention to the source of anything wooden entering the orchard, especially wooden bins and props.

Mating Disruption- Mating disruption works by preventing male moths from finding female moths for mating within blocks treated with the pheromone dispensers, Isomate-C Plus (codling moth) or Isomate CM Flex (codling moth) or Isomate-CM/LR TT (codling moth and leafrollers twin tubes). This control tactic is most effective when applied on an area-wide basis involving as many adjoining orchards as possible. Isomate-C Plus and Isomate CM Flex should be applied at a rate of 500-1000/ha (200-400/ac), Isomate-CM/LR TT at a rate of 750/ha (300/ac) before the first moths fly in the spring. Do not reduce the rate before consulting with the SIR program or your crop management advisor. Place the dispensers in the upper third of the canopy, preferably in shaded areas. Orchards less than 2 ha in size are not suitable for mating disruption. Growers should apply a border cover spray along edges adjacent to unmanaged sources of codling moth. Place additional dispensers in border trees to minimize the effect of immigration. Carefully read and follow the instructions provided with the dispensers.

Chemical Control

Only apply cover sprays in orchards or parts of orchards with an average capture over 2 consecutive weeks of two or more moths per trap per week over the 2 weeks, weather permitting. By using degree-day predictions to time the first spray, forecasting dates of codling moth egg laying and hatch is more accurate and spraying can occur when the control products can perform most effectively. Information on the approximate time of egg laying and hatch is available from most packinghouse field service offices and on the OKSIR web site (www.OKSIR.org/Degree Days). The OKSIR web site also lists the weekly accumulated degree day totals for 18 weather stations located within the OKSIR Program area. Because the optimum timing varies among the products based on how they control codling moth, first read the product labels to become familiar with the recommended timing.

The following table summarizes application information on control products recommended for codling moth control. Trade (product) names are linked to the Pesticide Label Search database of the Pest Management Regulatory Agency (PMRA). Click on the Registration Number of the product to read the current label. If more than one produt name appears on the list, click on the Registration Number of the product of interest.

Trade Name

Common Name

Target Stages

Maximum Number of Applications1

Spray Interval

(days)

Pre-harvest Interval (days)

Altacor

chlorantroniliprole

Larvae

10 – 14

Assail

acetamiprid

Eggs, larvae

Calypso

thiacloprid

Eggs, larvae

14 – 21

Confirm 240F

tebufenozide

Larvae

10 – 14

Delegate

spinetoram

Larvae

Entrust2

spinosad

Larvae

7 – 10

Exirel

cyantraniliprole

Larvae

10 – 14

Harvanta

cyclaniliprole

Larvae

3

10 – 14

Imidan WP

phosmet

Larvae

Intrepid 240F

methoxyfenozide

Eggs, larvae

Minecto Pro

abamectin + cyantraniliprole

larvae

n/a

Rimon

novaluron

Eggs, larvae

10 – 14

Virosoft CP4 or CyD-X

granulovirus

larvae

n/a

TwinGuard

sulfoxaflur + spinetoram

Larvae

1 As per label restrictions. 2 Suppression only

Apply Assail, Calypso, Intrepid, or Rimon during egg-laying starting around 150 degree days if codling moth damage was more than 1% the previous year. NOTE: Rimon is registered for use on apples only. Application rates for Rimon depend on the concentration (0.93 or 1.4 L Rimon/1000 L) of the spray mixture and the spray volume applied to provide thorough coverage (minimum 700 L/ha (283 L/acre)). Consult the product label before mixing Rimon 10 EC for correct spray volume according to tree height. Apply Altacor, Assail, Calypso, Confirm, Entrust, Exirel, Harvanta, Intrepid, Rimon, TwinGuard, or Virosoft after the degree-day total predicts that egg hatch is beginning (about 220-300 degree-days) and trap counts have reached the recommended treatment level. To be most effective, larvae must eat these products so thorough and timely coverage is essential. Apply Delegate once egg hatch is over 90% complete. Do not apply Intrepid after egg hatch is complete.

Apply additional first brood and second brood sprays only after pheromone trap captures reach treatment levels and the residual protection from sprays ends. Under low-rainfall conditions, Calypso provides about 2-3 weeks protection from codling moth damage; Assail, Confirm, Exirel, Imidan, Intrepid, and Rimon provide about 10 to 14 days protection. Larvae must eat Altacor, Assail, Confirm, Delegate, Exirel, Intrepid, and Rimon, to be most effective so thorough and timely coverage is essential.

Research shows that application of neonicotinoid products such as Alias, Assail and Admire may cause increased mite populations. Therefore do not apply more than two applications of Alias, Assail, Admire or Calypso either alone or alternately per season regardless of target pest (codling moth, aphids, leafhoppers, leafminers) to avoid mite flare-up. Rimon may also disrupt biological mite control. If Sevin is used as a thinning spray in the same block treated with Alias, Assail, Admire andéor Calypso, consider monitoring mite levels.

Pesticide resistance management – It is important to alternate application of insecticides from different chemical groups or with different modes of action in order to avoid development of pesticide resistance. All insecticide products have a pesticide Group number displayed on the label.

See the table in Chemical Groups and Pesticide Resistance Management which lists the Group numbers for all pesticides recommended in the Guide to aid in selecting insecticides to avoid pesticide resistance development.

Visit the OKSIR Program web site (www.OKSIR.org) for more information about colding moth control.

Note Number: AG0095
Published: June 2000
David Williams, Knoxfield

General information

Codling moth Cydia pomonella is the principal insect pest of pome fruit in Victoria and can damage almost the entire crop if not controlled.

Control of codling moth is the key to almost all other pest programs in pome fruit orchards since the chemicals commonly used to control codling moth have adverse effects on beneficial insect species, which contribute to biological control of other pests. As a result, regular seasonal chemical control programs are often required for control of minor pests.

Injury

Newly-hatched larvae (caterpillars) chew through the fruit skin and bore their way to the core. The presence in fruit of one or more holes plugged with frass (excrement) is characteristic of attack by codling moth. The larvae enter the fruit through the sides, stem end, or calyx end, and a syrupy substance may exude from the holes as the fruit matures. Similar damage can be caused by oriental fruit moth where pome fruit is grown near stone fruit.

Shallow entries called “stings” result when larvae penetrate a short distance and then die from insecticide poisoning or natural causes.

Description of life stages

The adult codling moth has a wingspan of about 12 to 18 mm and is about 10 mm long when at rest with the wings folded. Males are smaller than females. The forewings are brownish grey with several grey cross-lines. An iridescent coppery-brown spot is present near the tip of each forewing. The hind wings are pale grey with fringed borders.

The female moth lays eggs singly on leaves and fruit. The egg is flat, oval, 1 mm long, opaquely white when first laid and develops a red ring towards maturity. Just before hatching the black head of the larva becomes visible in the egg.

A newly-hatched larva is white with a black head. There are generally five larval stages, which can be identified by the width of the head. Average widths of larval head for the five stages are approximately 0.3, 0.5, 0.8, 1.2 and 1.7 mm respectively.

Fully mature larvae are about 15 mm long and creamy pink with a dark brown head.

They leave the fruit and form cocoons under loose bark on the tree or in litter on the ground beneath the tree. Depending on the time of year, the larva in the cocoon either diapauses (becomes dormant) until the following spring or forms a pupa from which the moth emerges about two weeks later.

Seasonal development

Over-wintering larvae pupate early in spring and this over-wintered population begins to emerge as moths about the time of bloom. The moths emerge usually in one or more periods of peak activity, each period referred to as a “flight”. Eggs laid during these flights give rise to the first generation of the new season. Adults of the first generation produce the second generation. Up to three generations per season may occur in Victoria, depending on prevailing weather conditions.

A varying proportion of mature larvae from the second generation enter diapause instead of emerging as adults during the current season. What proportion of larvae enters diapause depends on the temperature conditions during the season. Most of the larvae in the third generation enter diapause. Larvae that enter diapause spin cocoons within which they survive the winter.

Effect of temperature on codling moth

The body temperature of insects is closely related to the temperature of the surrounding environment. The growth of an insect increases as temperature increases until the optimum temperature for the particular type of insect is exceeded; at this point the growth rate rapidly declines (Figure 1). The temperature below which the growth of a given type of insect is assumed to be zero is called the lower developmental threshold for that insect and is estimated from the growth curve (Figure 1).

The lower developmental threshold for codling moth is 10 degrees Celsius. When temperature is traced through a series of days and compared to an insect’s lower developmental threshold the amount of its growth on any given day can be estimated. In Figure 2, the shaded area represents an estimation of insect growth in physiological time units called degree-days. A degree-day is essentially each degree of temperature by which the average temperature on a day exceeds the lower developmental threshold.

It is important to note that physiological time varies from day to day but chronological time is constant. The eggs, larvae and pupae of codling moth each have specific physiological time requirements to complete development before they transform to the next stage. Temperature also affects the flight, mating and egg laying activities of the adults. Although the minimum threshold for emergence of moths is 10 degrees C, male moths do not fly until temperatures exceed 13 degrees C and codling moths do not mate until temperatures exceed 16 degrees C. Table 1 lists the minimum thresholds and the physiological time requirements of codling moth during its various stages of development and activities.

Pheromone traps

Adult female codling moths release a sex-attractant chemical (pheromone) to attract male codling moths. Synthetic pheromones are used in traps to indicate the presence of male codling moths in orchards. Pheromone-trap catches and temperature records can be used to predict when the eggs resulting from a particular moth flight will be hatching. Such predictions, if accurate, should allow better timing of spraying. Further advice on the use of pheromones can be obtained from the author.

Table 1. Physiological time requirements and minimum thresholds for various stages and activities of codling moth

Stage Activity Minimum threshold (°C) Physiological time required (DD°)
Average Range
Adult Male flight 13
Mating 16
Egg laying 16
Egg Hatch 10 89 69 – 111
Larva Hatch to maturity 10 264 200 – 345
Pupa Pupation to emergence 10 222 133 – 325

Biological control

Codling moth eggs are preyed on by earwigs and mirid bugs but neither gives significant control. Wasps such as Trichogramma parasitise codling moth eggs and have been used with some success in Russia. Under Australian conditions, the rate of parasitism was too low for commercial use.

Removal of over-wintering sites by scraping loose bark from trees and maintenance of general orchard hygiene may help to reduce the survival of over-wintering populations. Similarly, provision of artificial cocooning sites such as bands of cloth or corrugated cardboard wrapped around the trunks allows over-wintering larvae to be trapped and destroyed. These methods are generally too time consuming and expensive for adoption by commercial growers.

Mating disruption is a technique in which the orchard air is saturated with pheromone emitted from slow-release dispensers. This prevents male moths from using pheromone, emitted from female moths, to locate and mate with the females. Mating disruption products are now available commercially for large-scale orchards.

Codling moth larvae are susceptible to infection by a virus that can devastate localised populations. The virus has been developed into a commercial product overseas but local trials in Australia have had disappointing results. A parasitic nematode has shown promise for control of over-wintering larvae.

Fig 1. Effect of temperature on the growth rate of insects.Fig 2. Effect of temperature on amount of insect growth

Chemical control

For recommendations on chemical control of codling moth refer to the current edition of the Orchard Pest and Disease Handbook available from district offices of DPI. For the registration status of chemical products, please refer to Australian Pesticides and Veterinary Medicines Authority (www.apvma.gov.au), your chemical reseller or your local chemical standards officer. Ensure you meet the relevant Maximum Residue Limits (MRLs) for the chemical in the end market, be it domestic or export. Chemical users must ensure they read and understand all sections of the chemical label prior to use.

Contact us

For information relating to the safe and appropriate use of chemicals, including management of chemical residues and licensing requirements, call our Customer Service Centre of 138 186 and ask to speak to your local chemical standards officer or visit:

Acknowledgements

This Agriculture Note was developed by David Williams, Farming Systems Research of DPI in June 2000.

It was reviewed by Harold Adem, Farm Services Victoria and David Williams, Farming Systems Research in May 2012.

How to safely control codling moths in home orchards

CORVALLIS, Ore.—The codling moth may be the most damaging insect in home orchards of apples, pears, plums and walnuts. The most common control method used by home gardeners is repeatedly spraying insecticides on the fruit throughout the growing season. But several other less toxic control methods are available, according to James Young, entomologist with the Oregon State University Extension Service.

Codling moths begin to emerge when apples are in bloom, usually in May or June. The adults are roughly 3/4 inch across the front wings and are gray-brown with lighter gray lines and golden or bronze areas near the wing tips. The larva or “worm” is about 1/2-inch long, white with a pink hue and a brown head.

Newly hatched larvae bore into developing fruit, feed for about three weeks, leave the fruit, pupate and emerge as adults about two weeks later (the second generation). Depending on location and length of the growing season, two to four generations can occur each summer.

The traditional control program is to spray trees with insecticide. But if you prefer to use greener methods, the following can reduce codling moth damage.

Pheromone lures and traps

“Pheromones are compounds emitted by female moths to attract a mate,” Young explained. “Synthetic pheromones, laboratory-made compounds, mimic their natural counterparts.”

Pheromone traps are made by attaching pheromones to a sticky bottom trap. Male moths are attracted to the scent and get stuck to the board. The traps monitor moth flight and indicate when you need to spray; only when it is necessary and most effective. If there are no other hosts (apples, pears, plums or walnuts) in the area, sometimes a large number of traps can attract and kill most of the males, significantly reducing breeding.

Sanitation and Banding

Sanitation is the most important practice that is environmentally safe (or safer). If you remove and dispose of damaged young fruit throughout the season, you can help reduce future generations. Larvae continue to feed inside the fruit after it falls from the tree. Remove fruit promptly.

Installing bands covered with Tanglefoot ™ (available from garden supply stores) around the trunk of your fruit trees, 18-24 inches from the ground, can also reduce populations. Mature larvae move down the tree in search of a place to pupate and can be trapped in the sticky substance. While this method reduces the population, it does not provide complete control because many larvae overwinter on the ground.

Bagging

Although time consuming, you can tie a paper sack around each apple and pear approximately six weeks after bloom. This will not affect the maturation of the fruit but will prevent some varieties from reaching their full color.

An OSU Extension Service publication, “Managing Diseases and Insects in Home Orchards,” (EC 631), is available online. Note that some of the pesticides listed in this document are no longer registered for use by homeowners to control codling moth. Remember to always read the label before purchasing and applying any product regardless of how many times you have used it before.

Apple Best Practice Guide

Codling moth (Cydia pomonella L.)

Adult codling moth

Codling moth egg

Codling moth larva in fruit

Codling moth entrance hole in fruit (‘sting’ injury)

Codling moth is a key pest of apple, which attacks the fruit directly causing economic damage at low population densities. It is sometimes very damaging to pear.

The life cycle involves one complete and one partial generation per year in southern Britain, though two generations occur in hot summers.

First generation adults emerge in May to July and fly at dusk on warm evenings. Eggs are laid singly on leaves and the surface of fruits. Larvae hatch after 7 10 days, depending on temperature, and cause damage by boring into the flesh of the fruit. A characteristic entrance hole is left, partially blocked by dry frass.

This readily recognised pest should be monitored using pheromone traps, monitored weekly from petal fall until harvest. The threshold is a single catch of 5 or more moths per trap per week from May to June (first generation, fruit less susceptible) and 3 per trap per week from August to Setpember (second generation, fruit more susceptible).

Control

In addition to sanitation measures which help reduce the worst ravages of attack, there are three different approaches for controlling codling moth:

  1. biological control with sprays of the codling moth granulovirus
  2. chemical control with sprays of insecticides which are either ovicidal, larvicidal or both
  3. sex pheromone mating disruption with a grid of Exosex autoconfusion dispensers.

Biological control

Now that the codling moth granulovirus (Carpovirusine, Cyd-X, Madex Top) is available, it should be used wherever possible, bearing in mind the following limitations:

  • It only controls codling moth and not tortrix moths, Blastobasis or other pests
  • A maximum of ten sprays each (Madex Top) giving 8-14 days protection is allowed per season (a maximum of six sprays per generation)
  • Application should be made just before egg hatch is expected to ensure larvae pick up virus particles as they move from the egg to the apple entry point. Application a little bit too early is preferable to a little bit too late.
  • Heavy attacks may result in some superficial sting injury as the young larvae hatching from eggs do not die immediately.

Chemical control

A chemical control programme should comprise a series of sprays of insecticides at 2-3 week intervals, maintaining an insecticide deposit throughout periods of risk.

  • The interval between sprays should be 2 weeks if temperatures are high or if the risk is high.
  • The choice of insecticides is chlorantraniliprole applied at or shortly before the onset of egg laying, or indoxacarb (Steward), methoxyfenozide (Runner) or spinosad (Tracer) applied at the onset of egg hatch.
  • Use of synthetic pyrethroid insecticides, which are very effective, should be avoided as they are harmful to predatory mites and many other important natural enemies.
  • The onset of egg laying is when a threshold pheromone trap catch is exceeded.
  • Egg hatch occurs 7-10 days later.
  • The interval between egg laying and egg hatch can be estimated more precisely by accumulating percentage egg development amounts calculated from daily maximum and minimum air temperature.
  • First egg hatch is expected when the accumulated sum reaches 100%.
  • Be vigilant for second generation attacks, which occur in August in hot summers.

Sex pheromone mating disruption

RAK 3+4 is a combined pheromone control system which reduces fruit damage from codling moth (RAK 3) and summer fruit tortrix (RAK 4). Both pheromones disrupt mating behaviour and therefore prevent populations from developing. The pheromones are released from sealed chambers by volatilisation, preventing male and female moths from locating each other and reproducing.

  • RAK 3+4 is most effective in orchards with a low pest population density. It should not be used in orchards where more than 1% of fruits (including fallen fruits) were damaged by codling and tortrix moths in the preceding year, unless the first generation of moths is treated with a control product to reduce initial populations.
  • Best results are achieved in isolated orchards, i.e. those which are 100 m or more away from other orchards or high trees.
  • Optimum results are also achieved in grouped orchards containing trees of similar size and shape.
  • RAK 3+4 will not be effective if there is a high density of codling moth and/or tortrix moth in the area adjacent to the orchard being treated. It will not be effective in orchards less than 1 ha in area.
  • Further details on time of application, dose and positioning of dispensers.

Products approved for control of codling, tortrix moths or caterpillars on apple

Choice of insecticides – efficacy factors

Active ingredient Trade name (examples) Class1 Selectivity Label rec’s2 Safety to Typhs Suggested interval between sprays(days)
adoxophyes orana granulovirus Capex microbial biocontrol highly selective sft safe Max = 10 days
Bacillus thuringiensis var. kurstaki Dipel DF bacterial selective c safe 7
chlorantraniliprole Coragen anthranilic diamide selective c safe 14
E8, E10-dodecadienol, Z11-tetradecenylacetate, n-tetradecylacetate RAK 3+4 sex pheromone mating disruption highly selective cm, sft safe none stipulated
codling moth granulovirus Carpovirusine, Cyd-X, Madex Top microbial biocontrol highly selective cm safe 8 sunny days
deltamethrin Decis pyrethroid broad spectrum cm, t harmful none stipulated
indoxacarb Steward oxadiazine selective c, cm, ftt, sft u 10
methoxyfenozide Runner MAC selective c safe u
spinosad Tracer neural blocker selective C, cm, ftt,sft safe u

Read and follow the label before applying any sprays

Hazards3 Harvest interval(days) Max. no. sprays Buffer zoneWidth (m)
Anticholin-esterase? Humans Fish & aquatic life Bees
adoxophyes orana granulovirus no u u u 0 4 0
Bacillus thuringiensis var. kurstaki no u u u Varies with product Varies with product 5
chlorantraniliprole no h ed h 14 2 10
E8, E10-dodecadienol, Z11-tetradecenylacetate, n-tetradecylacetate no u t u None stipulated 1 u
codling moth granulovirus no h,i u u Varies with product Varies with product 0
deltamethrin no i,h ed d 7 u 50
indoxacarb no h ed u 7 3 15
methoxyfenozide no u u u 14 3 5
spinosad no u ed u 7 4 40
Keys: 1CSI=chitin synthesis inhibitor, JHA=juvenile hormone analogue MAC= moulting accelerating compound 2c=caterpillars, cm=codling moth, ftt=fruit tree tortrix, sft=summer fruit tortrix, t=tortrix 3d=dangerous, ed=extremely dangerous, h=harmful, ir=irritant, t=toxic u=no hazard specified

Control in organic orchards

Organic growers should use multiple codling moth granulovirus sprays (up to 6 applications per generation and not exceeding 10 applications per season for Madex Top) and in combination with season-long maintenance of a pheromone autoconfusion system.

  • Note that Bacillus thuringiensis has little effect on codling moth.
  • Cultural control remains an important additional measure.

A live codling moth about to drill a hole in your poor apple.

In Western Washington, our apple trees have two major enemies: codling moths and apple maggots. While codling moths can be a nuisance (they don’t ruin the apple), apple maggots can leave the entire fruit bitter and unusable, even for cider. Yet some of the easy solutions for apple maggots don’t protect from codling moth.

The good news is, there are organic, chemical-free methods for keeping your trees safe, including the paper bag method and the legging method.

The Bagging and Legging Methods

The legging method uses stockings or nylons, tied over and covering your apples completely. It’s quite effective against apple maggots, but not against codling moths. To be fully effective against codling moths, you need to spray the stockings with kaolin clay after you’ve covered the apples with them. Kaolin clay also needs to be reapplied every week or two depending on rain (nope – not happening).

Apples wrapped with leggings.

We recommend the paper bag method. The paper bag method has several pros and cons.

Pros:

  • Is a one-step process.
  • Keeps out both codling moths and apple maggots.
  • Uses affordable materials.
  • Prevents sunburn on apples.
  • Thanks to thinning of fruit before bagging, can result in larger apples.

Cons:

  • Can be difficult to apply if the paper bag is too thick.
  • Doesn’t keep out earworms, which can poke holes in the bags and let in codling moths.
  • Is time-consuming.
  • Doesn’t work with short-stemmed varieties of apples.
  • Red apples may not see full color development.

When To Start

Codling moths and apple maggots can infest your apples a few weeks after they bloom, so apply paper bags before these insects can do much damage to your trees.

We recommend bagging your apples when they’re between ½ to an inch in diameter. That should be about four to six weeks after they bloom.

Step One: Thin The Fruit

Remove the two apples with Xs over them, keep the big one on top. Or keep one of the other ones in the trio.

Before you begin to bag your apples, you need to thin out the trees in anticipation of June drop. If you’re unfamiliar with June drop, it’s when apples fall before harvest because there were too many blooms growing from the same stem. This can lead to a big mess for you and is a buffet for hungry herbivores or insects who come across your orchard.

Make a few passes around your tree and remove any extra apples from clusters. Leave the biggest ones on the tree. This is also a good time to see if any codling moths or apple maggots have already infested some of your fruit.

You’ll drop tons of apples – always good to have a tub around to collect them. If you just drop them on the ground they could attract other pests.

As for those now-discarded apples? Don’t leave them on the ground or they may still attract maggots and moths. Add them to your compost, or feed them to chickens or other livestock.

Step Two: Add The Bags And Ties

For bagging apple trees, one good option is using small to medium paper bags and simple paper twist ties.

Paper bags in a box. Hundreds of twist ties saved up for an occasion like this.

First, you’ll want to prep your bags. As you can guess, these bags weren’t made specifically for fitting around apple stems. Since you don’t want any space between the bag and the apple stem, the large opening can make bagging apples a little tricky and slow.

To speed things up, take an assembly line approach. Take the bulk of your bags and start bunching up the openings. Afterwards, take your twist ties and separate them along their perforated edges if they haven’t been already.

Now you’re ready to add the bags and ties to your apple tree. The bags should completely cover the fruit and should be tied around the stems. Avoid bagging many leaves and branches with your apples, though it’s fine to include a leaf here and there.

You will probably knock 1/3rd of the apples off the tree while doing this – it takes a soft touch.

The most important part of apple bagging is to attach your ties tightly. The more space between the folds of the bag and the stem, the easier it will be for apple maggots and codling moths to infest your fruit.

A successfully bagged apple!

Step Three: Additional Prevention

If you want to be extra cautious,there are other chemical-free methods that can reduce the risk of codling moths and apple maggots.

Companion Plants For Apples

When it comes to reducing pests, companion plants can either attract predators to those apple-destroying insects or can confuse the senses of those bugs. Parsnip is particularly effective against codling moths.

Other reportedly effective companion plants for apples include:

  • Nasturtiums which repel codling moths and more when planted around the base of your fruit trees
  • Hyssop, which attract beneficial insects
  • Sage, which deters codling moths with its high camphor content
  • Tansy, which also boasts a high camphor content (be careful with tansy, as it’s toxic when eaten)
  • Chives, which help apple scab but not moths and maggots

Codling Moth Traps

In the rainy Pacific Northwest, tent-shaped hanging codling moths traps are most effective when put out by the end of March or earlier. Unfortunately, traps alone are not effective at keeping overall pest populations down.

Apple Maggot Traps & Prevention

The most popular apple maggot traps also hang from your trees, but are red and spherical rather than tent-shaped. These spheres are then covered with tanglefoot. An additional benefit of apple maggot traps is that they’re reusable from year-to-year. These traps are most effective when placed a week or two before buds break in early spring and should be left out until harvest.

You can also enlist some hungry chickens to help you reduce your pest problem. Run a few chickens underneath your trees to eat any apple maggots that may have dropped out of apples from late June to October, and you’ll see fewer maggots next season.

Step Four: Monitor Your Apples

The two things you need to monitor your bagged apples for are earworms and ripeness.

As we mentioned earlier, paper bags don’t protect against earworms. The good thing about earworms is that they eat codling moths. The bad thing about them is that when they eat a hole in your bag, they let more codling moths in. Check weekly to ensure that there are no holes in your bags. If there are, they were likely caused by earworms, and you’ll need to rebag those apples.

Since you won’t get your usual visual clues, you’ll also need to monitor your apples for ripeness. As you get close to harvest, remove a bag or two from your apples. You can tell ripeness by color, ease of removal from your trees, brownness of seeds, and flavor. If the apples aren’t ready yet, check again in a few days.

Again, red varieties of apples won’t gain their full color if they’re bagged, so you may want to remove your bags one to two weeks before you plan on harvesting your apples. Removing the bags early may allow codling moths and apple maggots to infest your apples before they can be picked. If the red color isn’t important to you, you can leave those bags on until the apples are harvested.

More Great Codling Moth Resources:

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