Peach tree borer spray

Contents

Colorado State University

Print this fact sheet

by W.S. Cranshaw* (1/18)

Quick Facts…

  • The peachtree borer is the most destructive insect pest of peach, cherry, plum, and other stone fruits in Colorado.
  • Damage is done by the immature larvae, which chew beneath the bark of the lower trunk and larger roots.
  • Insecticide sprays applied to the lower trunk when eggs are being laid can prevent new infestations.

Figure 1: Gumming produced at the base of a tree due to wound by a peachtree borer larva. Photograph courtesy of James Solomon, USDA Forest Service

Figure 2: Peachtree borer larvae in roots of a peach. Photograph courtesy of Eugene Nelson, Colorado State University.

Figure 3: Peachtree borer larva in the base of a peach.

Figure 4: Peachtree borer eggs. Photograph courtesy of Ken Gray Collection, Oregon State University

Figure 5: Pupa and pupal cocoon of a peachtree borer.

Figure 6: Pupal skins extruding from base of a tree after adult emergence. Photograph courtesy of David Shetlar, Ohio State University

Figure 7: Peachtree borer, adult male.

Figure 8: Peachtree borer, adult female. Photograph courtesy of David Leatherman.

Figure 9: Peachtree borer males attracted to a trap baited with a sex pheromone lure.

Peachtree borer (Synanthedon exitiosa) is the most destructive insect pest of peach, cherry, plum, flowering plum and other stone fruits (Prunus spp.) in Colorado (Figure 1). The grublike larvae chew underneath the bark at the base (crown) of the tree and on larger roots, habits that lend it another common name “peach crown borer” (Figure 2). The gouging wounds they produce can be quite extensive and may seriously weaken and even kill trees, but may not be obvious unless the area around the base of the tree is examined.

External evidence of peach tree borer tunneling is a wet spot on the bark or the presence of oozing, gummy sap. The sap is clear or translucent and often dark from the sawdust-like excrement of the insect. Most injuries occur along the lower trunk beneath the soil line. Lower branches rarely receive injuries. (Note: Oozing wounds on peach that produce an amber-colored gum may be caused by cytospora canker http://extension.colostate.edu/topic-areas/agriculture/cytospora-canker-in-tree-fruitcrops-2-953, a common fungal disease of stone fruits that produces symptoms that may be mistaken for those produced by peachtree borer. The presence of small particles of wood and bark within the gum distinguish damage by peachtree borer.)

Life History and Habits

The life cycle of the peachtree borer requires one year to complete. Only the immature (larva) stage (Figure 3) produces the damage to trees. Upon hatching from the eggs (Figure 4), young larvae immediately tunnel into the sapwood of the tree, usually through cracks and wounds in the bark. Larvae continue to feed and develop until the onset of cold weather. Most activity occurs a few inches below ground on the trunk and larger roots. The insects spend the winter as partially grown larvae below ground under the bark.

With the return of warmer soil temperatures larvae resume feeding and most injury is produced in mid-to late spring as the larvae mature. The larvae finish feeding and change to the pupal stage in late May through early July. Pupation occurs in a cell made of silk, gum and chewed wood fragments, located just below the soil surface (Figure 5).

The adults emerge within a month and in the process often will pull out the pupal skins, which may be then be seen around the base of the trunk (Figure 6). Adults of the peachtree borer (Figures 7, 8) are a type of “clearwing borer” moth that resemble wasps, but they are harmless and incapable of stinging. Unlike most moths peachtree borers (and other clearwing borers) fly during the day time.

The first adults, males, may emerge in as early as mid-June. However, females usually follow by a couple of weeks and most adult activity – mating and egg laying – occurs during July and August. During this time the female moths lay eggs on the bark of the lower trunk and in soil cracks near the tree base. Eggs generally hatch in about 10 days.

Preventive Sprays

Peachtree borer is most easily controlled by sprays of insecticides applied to the lower trunk and base of the tree. These are preventive sprays that target the eggs and early larval stages exposed on the bark of the tree. Once larvae have migrated into the tree, insecticides are not effective.

Depending on seasonal temperatures one can expect peachtree borer to begin laying eggs in very late June or early July. Most all eggs will be laid during July and August, although a few adults may still be present into September.

A way to best determine when adult peachtree borers are locally active is through use of traps. Various designs of traps, usually with a sticky bottom, are used and all capture adult males. These are lured into the trap by a chemical (sex pheromone) that mimics what female peachtree borers use to attract mates (Figure 9). Such traps can give one an idea of when adults are present, which is associated with periods when eggs are being laid.

In the absence of using these traps, as a general guideline, preventive trunk sprays should be applied around the first week of July. Where large numbers of peachtree borers continue to be active later in summer it may be useful to make a second application in early August.

To be effective as a preventive spray, the insecticide must have some residual activity, allowing it to kill young peachtree borer larvae emerging from eggs for several weeks after application. Presently certain formulations containing the active ingredients permethrin (Astro, Hi-Yield 38, etc.) or carbaryl (Sevin) are the only insecticides that can legally be used backyard fruit trees, have reasonably good residual activity on bark after application, and are labeled for control of peachtree borer.

* Colorado State University Extension entomologist and professor, bioagricultural sciences and pest management. 3/02. Revised 1/18.

Go to top of this page.

Lesser Peachtree Borer

The lesser peachtree borer, similar to the peachtree borer, is a native North American pest that causes serious damage to peach, cherry, plum, nectarine, and apricot trees. Borers underneath the bark can be some of the more difficult insect problems to manage in stone fruits. While the peachtree borer and lesser peachtree borer are similar in biology and management, there are some significant differences. The peachtree borer primarily attacks young non-bearing or unmanaged trees at or below the soil line. The lesser peachtree borer attacks older trees and does not confine its activity to the lower trunk but can be found in the scaffold limbs, branches, and the trunk above ground.

Larvae of the lesser peachtree borer are usually found under the bark of wounds. Infestation by the lesser peachtree borer is often identified by oozing of gum on the outer bark where the borer started its attack. The gum is usually mixed with reddish-brown frass. Bark eventually peels off of damaged areas, predisposing the tree to attack by other pests and diseases. Frequently empty brown pupal cases can be found partially exposed at the head of the larval gallery. Branches can be girdled by these borers and die.

Adult male and female lesser peachtree borers are similar in appearance and look more like wasps than moths. Unlike most moths, these fly during the day and are most active from 10 a.m. to 2 p.m. Lesser peachtree borer moths are slender, dark blue with some pale yellow markings, and both pairs of wings are clear, except for the edges and veins that have blue black scales. The antennae of the male are finely tufted. Lesser peachtree borers resemble the male peachtree borer. The second and fourth abdominal segments of the lesser peachtree borer have narrow yellow bands, while the male peachtree borer has 3 to 4 narrow yellow bands on the abdomen.

Larvae of the lesser peachtree borer are similar to other clear-wing borer larvae. They are about 1 inch long when mature. The head is light brown and the body is creamy white, but may be pinkish in some individuals.

Biology

Lesser peachtree borer overwinters as larvae underneath the bark. Larvae of all stages except the first may be found during the winter. The larvae feed for a period in the spring before burrowing just below the surface of the bark to pupate. Borers remain in the pupal stage from 18 to 30 days before emerging as adults. Female moths deposit eggs in small clusters in cracks and crevices near wounds between ground level and eight feet high. Females lay an average of 400 small oval, reddish brown eggs. Larvae begin to hatch in 8 to 10 days and burrow into the bark, often entering through cracks caused by other factors such as winter injury, pruning scars or machinery wounds. Moths emerge from early May until late September in Kentucky, USA. There are two generations per year with adult emergence in May and June, then again in August and September.

Prevention is the Key to Control

Control of lesser peach tree borers in commercial orchards relies on preventing larval establishment underneath the bark. Once under the bark, chemical control is usually ineffective. Insecticides should be timed just before or to coincide with egg hatch. To aid in the timing of sprays, pheromone traps are used to alert producers to the presence and activity of moths. Because egg hatch begins about 8 to 10 days after moth emergence, insecticidal sprays should be applied 7 to 14 days after the first moths are captured in the traps. With trees that show little or no lesser peachtree borer activity, a single insecticide application can be used to coincide with the peak of the second generation flight (usually early September). Trees that have had problems with lesser peachtree borer may require two applications, one 10 days after initial moth flight (mid May) and the other at peak of the second generation flight (early September).

In commercial orchards, insecticides applied with an air-blast sprayer will do little for lesser peachtree borer control. Directed sprays should be applied uniformly to drench the trunk and scaffold limbs to about eight feet above ground. Thorough coverage of the trunk and limbs is necessary.

Monitoring

To determine the most effective time to apply an insecticide, pheromone traps should be used to monitor moth activity. These lures are synthetic copies of the chemicals female moths use to attract their mates.

A trap consists of plastic top and bottom held together by a wire hanger with the lure placed inside.

Figure 1. Lesser peachtree borer stuck on pheromone trap.

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 tree 4 to 5 feet off the ground, usually one for each ten acres of trees (minimum of two traps per orchard) in commercial orchards.

For a list of source of the various types of pheromone traps, see ENT-54, Vendors of Microbial and Botanical Insecticides and Insect Monitoring Devices.

It is important to note when moth flight begins and when emergence reaches its peak. Moth activity can occur anytime between mid May and late September. In order to detect the first activity, traps should be hung in the trees well in advance of the anticipated flight. Trapping should begin in late April. Trap lures need to be replaced once a month. Trap bottoms should be replaced when the sticky surface becomes clogged with other debris.

Proper identification of the moths captured in the trap is essential. There are other moths which may wander into the trap, even other clear wing moths. Captured moths should be examined carefully to be sure that they are the correct species.

Worming Trees

Before the development of chemicals for controlling lesser peachtree borer, producers relied on digging the borers out of the bark by hand. This is still an alternative for backyard gardeners. In the spring, about the time of bud break, insert a knife or wire into the galleries to locate and remove or smash the larvae. Care should be taken not to cut the sound bark more than necessary, and cutting should be done vertically. Carelessness may result in more damage to the tree than the damage that would have been caused by the borers!

Revised: 11/19

Tips For Peach Tree Borer Control

One of the most destructive pests to peach trees is the peach borer. Peach tree borers can also attack other pitted fruit-bearing trees, such as plum, cherry, nectarine and apricot. These pests feed under the bark of trees, weakening them and leading to death. Keep reading to learn more about how to control peach tree borers.

How Peach Tree Borers Damage Trees

Peach borer larvae tunnel through cracks and wounds within bark, feeding on the sapwood. Peach tree borers attack near the soil line, with most activity occurring a few inches below the ground. Eventually, the bark begins to peel off damaged areas, making the tree susceptible to other pests and disease.

Adults, which resemble wasps, are most prevalent from mid-May to early October. During this time, eggs are laid on the trunks of trees, hatching within a week

to ten days. Evidence of peach borer damage can usually be seen in spring and summer, with affected trees quickly declining in health.

Generally, when these pests are present, trees will exhibit an oozing, clear gum-like sap (not to be confused with the amber-colored sap attributed to canker) mixed with sawdust. The whitish larvae may also be seen.

How to Control Peach Tree Borers

Peach tree borer control can be difficult, as the larvae are not easily accessible beneath the tree bark. Most effective control methods consist of preventive insecticides targeted at the egg or early larval stage. These usually contain permethrin or esfenvalerate.

Borers may also be controlled by applying paradichlorobenzene (PDB) crystals around the base of trees in fall, taking care not to come in contact with the tree itself.

Amounts used will vary, depending on the tree’s age and size, so read and follow instructions carefully. In addition, proper care and overall maintenance of trees are important preventive measures.

What and When to Spray for Peach Tree Borers

When spraying trees to control peach borer pests, choose those with lindane endosufan or chlorpyrifos. Sprays should be mixed according to label instructions. They should also be applied so that it runs down the trunk and soaks into the ground around the base. Try not to spray on foliage or any fruit that may still be on the tree. The best time to spray trees is within the first or second week of July and again in late August or September.

Peach and nectarine-Peachtree borer

Synanthedon exitiosa

Pest description and crop damage Adult is a steel-blue, clear-winged moth. The female is similar in appearance, but has smoky-colored wings and an orange band around her abdomen. Adult flight is usually from late June through September and eggs are laid at or on the base of the fruit tree. Larvae burrow in the crown and roots, girdle young trees, and weaken others. A single larva is capable of girdling a newly-planted fruit tree. Larval presence can best be detected by globs of gum mixed with a granular brown frass (excrement) that appear at the base of infested fruit trees. Full-grown larvae are 1 to 1.5 inch long with a whitish body and a brown head.

Biology and life history The borer overwinters as a larva under the tree bark, usually below soil surface. As temperatures rise above 50°F in the spring, the larva resumes feeding on the tissues under the bark. Larvae reach maturity in May to June and pupate in trees. Adult moths emerge beginning in June and continue to emerge through September. Mating and egg laying occurs throughout this period. The young larvae hatch after 8 to 10 days and bore immediately into the base of the tree. Larvae in the bark above the soil surface usually do not survive the winter in cold areas.

Pest monitoring Periodically scout the base of the trunk near the soil surface for excessive gumosis mixed with granular frass. Pheromone traps are available to monitor adult male moth activity.

Management-cultural control

Protect the base of the fruit tree from larval entry by placing a plastic or metal cone or barrier around it before egg laying begins. The cone should be pushed 1 to 2 inches into the soil and should fit snugly around the trunk at the top to prevent the tiny larvae from getting beneath it. Alternatively, if there are only one or a few peach trees in a home orchard, it may be quicker and cheaper to control this insect by “worming.” Use a pocket knife, wire or some pointed instrument to remove dirt around the tree and dig out the larvae.

Management-chemical control

Spray applications, and more importantly pesticide residues, on the trunk of the tree can prevent newly-hatched larvae from boring beneath the tree bark and entering the woody trunk where they are protected from all insecticide sprays.

Management-chemical control: HOME USE

  • azadirachtin (neem extract)-Some formulations are OMRI-listed for organic use.
  • gamma-cyhalothrin
  • lambda-cyhalothrin
  • pyrethrins-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin

Management-chemical control: COMMERCIAL USE

Spring applications

Dispensers must be in the orchard before adults begin flying, typically in late June. Place dispensers in the upper half of the tree. Some formulations are OMRI-listed for organic use.

  • Isomate P Pheromone at 100 to 250 dispensers/a.

Spring and summer sprays

  • chlorpyrifos (Lorsban Advanced) at 3 pints/a. REI 4 days. PHI 14 days. Apply only once per year. Apply as a low-pressure spray. Thoroughly wet all bark from ground to scaffold limbs. See label for preplant dip application. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • esfenvalerate (Asana XL) at 4.8 to 14.5 fl oz/a. REI 12 hr. PHI 14 days. Apply as directed trunk spray using thorough coverage. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • permethrin (Pounce 25WP) at 6.4 to 16 oz/a. REI 12 hr. PHI 14 days. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.

The peach tree borer (Synanthedon exitiosa) does damage to a variety of stone fruit trees. It attacks not the fruit, but the tree itself, burrowing into its trunk near or beneath ground level and devouring its way into the living cambium layer underneath.

Heavy infestations, recognizable from the circle of oozing frass (the larvae’s excreted waste) around the trunk, can completely girdle trees, killing them if left untreated. Young trees are especially vulnerable. Older trees that survive attacks will show less vigor and inferior fruit quality.

Borers are historically found across the United States and in parts of Canada, almost anywhere stone fruits grow. They existed on wild cherry and plum trees before non-native apricots, nectarines and peaches were introduced. Today, they’re a common and persistent threat to both commercial and home orchardists.

The larvae of peachtree borers are white to beige and brown and obtain an length of an inch or more. The chewing end of the larvae darkens as it matures. Despite they’re size, they’re seldom seen as they bore beneath a tree’s bark, gouging out wide, fass-filled tunnels. Pupae, wrapped in silky cocoons, are also unseen hidden inside the tree.

Adult moths have translucent wings and resemble wasps. Females are metallic blue and marked with an orange band on their abdomen. Males are smaller and are marked with yellow stripes. Their emergence a week or two into the summer sets off a frenzy of mating and egg laying.

The lesser peachtree borer (Synanthedon pictipes) is found in the eastern United States, across the southern states to Texas and the midwestern states to Minnesota. It attacks more of the tree, including primary limbs, and is more likely than Synanthedon exitiosa to produce eggs throughout the season. Larva are similar in appearance to exitiosa, but male moths have narrower, more numerous yellow bands across their abdomens. The pest’s life cycle and treatment is similar to those of exitiosa.

Life Cycle

Adults begin emerging in late spring and early summer from larvae that have overwintered inside the tree an inch or two beneath the soil line. They continue to emerge throughout the summer and into the fall. Knowing when moths first emerge in your region, as early as April in Georgia and other warmer areas but more commonly in May and June, is critical to controlling the pest.

The moths begin breeding almost as soon as they emerge. Females lay as many as 400 eggs on the trunk of the tree near the soil line or in the soil against the tree. The eggs take ten days to hatch.

Larvae immediately seek entrance into the tree’s bark, often through cracks, chips and other damage. They tunnel through the bark into the vulnerable cambium layer beneath it and beyond, growing as they do. Some may pass through to adult stage in a single season. As cold weather sets in, larvae will reduce activity and overwinter inside the tree. They begin feeding again when temperatures warm.

In spring, the larvae migrate from their holes, pupating near the entrance to their burrow or in nearby soil, creating a gummy cocoon of silk thread and bits of wood. The cocooning and pupation stages before moths emerge takes as much as four weeks. Moths begin laying eggs within minutes of taking to the air.

Utah State University Extension Cooperative (PDF) has wonderful color photographs of the pest’s various stages.

Damage

Peach tree borers bring major harm to important fruit-crop trees, destroying the tree’s vascular system through boring and girdling while inducing plant pathogens to invade the weakened tree.

Colorado State University’s Extension website doesn’t pull punches when addressing the pest’s effect on home and commercial growers, calling it “the most destructive insect pest of peach, cherry, plum and other stone fruits in Colorado.” The University of Florida’s Institute of Food and Agricultural Sciences provides perspective: “The peachtree borer and the lesser peachtree borer, Synanthedon pictipes, account for more damage to peach trees than all other insect pest combined.”

Borer damage inhibits the conduction of water and nutrients up the trunk to the tree’s branches, leaves and fruits. One or two borers will harm its growth and fruiting. Several burrowing into the same tree, fouling their tunnels with their waste, can kill a newly infested tree in a single season.

Infestation are most common in older trees that have seen damage from canker, harsh winters, pruning and mechanical injury (like trunks being hit by mowers). This give the larvae an easy way into the tree’s insides. The lesser peachtree borer is particularly attracted to older, damaged trees. Numerous larvae cluster at these places in “galleries” where substantial damage may be done.

The Missouri Botanical Garden has photos of damage signs as well as the larvae at work.

How to Control

  • Don’t allow borers to get established. Most trees will survive attack from small numbers. But large numbers of larvae can completely girdle a tree, killing it. Once the larvae move into the bark, they are difficult to manage. They’re most vulnerable at the surface before they chew their way into the tree’s bark and cambium layer.
  • Wild trees provide a year-to-year home for borers. If you have wild plum, cherry or other stone fruits in your woodlot, consider clearing them. Female adults are attracted to diseased, damaged and otherwise stressed trees. Removing and replacing older, stressed trees that harbor borers can help make control issues easier to deposit their eggs.
  • Healthy, adequately watered trees are less likely to invite infestation. Take care to keep your trees strong and undamaged.
  • Borer treatment begins early in spring even before larvae become active. Probe small holes in trunks near the soil line, especially those with evidence of frass, with the point of a knife or stiff wire to crush larvae (and later pupae) beneath the bark. In severe infestations, scoop soil out from around the crown of the tree where frass collects and use a sharp-pointed object to dig out the larvae, taking care not to harm the tree.
  • Be on watch and prepared for the emergence of adult moths. Because they begin breeding and laying eggs within hours of emerging, it’s important to treat for them as soon as they appear. Ask local nurserymen when the first moths are expected in your area. Monitor trees for moth activity daily and keep journal records for future years. Use pheromone traps or Tangle-Trap® Insect Trap Coating to capture adults. Inspect traps daily.
  • Begin spraying organic neem oil in the highest recommended concentrations around the crown of the tree and up the first six to 12 inches of the trunk when adults are anticipated. Saturate both bark and soil. The oil will disrupt the moths’ breeding cycle and discourage them from leaving eggs. It will also neutralize eggs that may already have been laid as well as penetrate the bark and inhibit development of larvae already in the tree. Spray twice a month throughout the breeding season which can last until September. Reapply after rains.
  • Citrus extract sprays will repel adults and discourage egg laying. Begin spraying trunks and around the crown of the tree just ahead of moth hatch.
  • Paint tree trunks and exposed roots with a paste of Surround WP, a powder made of kaolin clay. Coat base of tree, exposed roots and trunk up to 12 inches. Once dry, the coating deters adults and their egg laying.
  • Applications of Bt (Bacillus thuringiensis), a naturally occurring soil bacteria, will disrupt larvae and kill them depending on exposure. Spray Bt directly into borer holes after clearing out as much frass as possible.
  • Spinosad, an OMRI listed pesticide, can also be sprayed on tree trunks as larvae hatch and directly into borer holes. Spraying can be repeated every five or six days up to two weeks before harvest.
  • A recent study has shown that beneficial nematodes work against this destructive scourge. Nematodes attack eggs, larvae and pupae of numerous insect pests in soil. A spring application of nematodes suppressed 88% of orchard borer infestations. Spring and fall applications were found to be 100% effective.
  • Parasitic wasps can help with lesser peach tree borer whose eggs can be found. They are not effective on the pupae of the common, greater peachtree borer because they’re under the soil line out of the wasp’s reach. But certain wasps will parasitize eggs found on bark and just-hatched larvae that have not yet worked their way into the tree.
  • Woodpeckers and other birds will reduce numbers by grabbing larvae on and under the bark. Encourage them by providing suitable habitat and not spraying harmful pesticides.
  • Cedar chips and bark spread around the base of stone fruit trees is said to repel egg-laying adult moths. In the south, spreading tobacco dust around the base of trees is a traditional method of discouraging pests.
  • Some do-it-yourself sources advise the use of moth crystals to “gas” the larvae inside their burrows. It’s suggested that crystals worked into the soil at the trees crown will emit vapor that penetrates into the tree. Moth crystals, like moth balls, are made from napthalene, a suspected carcinogen which is also linked to liver failure and neurological damage in infants. Using and handling naphthalene — not a natural-gardening practice — should be avoided.

Peachtree Borer

University of Kentucky College of Agriculture

The peachtree borer is a native North American pest that causes serious damage to peach, cherry, plum, nectarine, and apricot. Damage is caused by the larval stage, primarily to younger trees. Larvae tunnel into the roots and lower trunks of the hosts feeding on the growing tissue and inner bark. Young trees may be completely girdled and older trees may have their crop bearing capacity greatly reduced. Infested trees may yellow and eventually die as the larvae girdle the tree at the crown.

The adult peachtree borer is a clear wing moth with a 1-1/4 wing span. Unlike the majority of moths, these fly during the day and are most active from 10 a.m. to 2 p.m. The female and male moths differ in appearance. The female is dark, steel blue with one or two wide orange bands around her abdomen. Her front wings are opaque while the hind ones are clear. The male moth is smaller and more slender. It is also steel blue, but has several narrow-yellow bands around the abdomen. Both pairs of wings are clear.

Figure 1. Female peachtree borer with the characteristic dark wings and banded abdomen.

Egg laying begins shortly after the moths emerge and lasts only a few days. The eggs are deposited on the trunk at or near the base. Females lay 500-600 eggs on average. The larvae will begin to hatch in 9 to 10 days. Upon hatching, the larvae wander down the trunk to the soil line and burrow into the bark, often entering through a crack or wound. When full grown, the larva is 1-1/4 in long, cream colored with a dark brown head. The winter is spent as a larva under the bark. In the spring the larva will construct a silken cocoon and cover it with tiny bits of chewed wood. The borer will remain in the pupal stage from 18 to 30 days before emerging as an adult. There is a single generation per year. Infestation by the peachtree borer is often identified by oozing of gum around the base of the tree. The gum is usually mixed with dirt and reddish-brown frass. Frequently empty brown pupal cases can be found around the base of damaged trees, either at the head of the larval gallery or in the soil close to the tree trunk.

Figure 2. Male peachtree borer caught in pheromone trap. Note the clear wings and narrow bands on the abdomen.

Prevention Key to Control

Control of peach tree borers in commercial orchards relies on preventing the larval establishment underneath the bark. Once under the bark, chemical control is ineffective. Insecticides should be timed to coincide with initial egg hatch in order to be effective. To aid in the timing of sprays, pheromone traps are used to alert producers to the presence and activity of peachtree borer moths. Because egg hatch begins about 9 to 10 days after the moths emerge, insecticidal sprays should be applied 7 to 14 days after the first male peachtree borer moths are captured in the traps.

Sprays containing Asana XL, Lorsban, and Warrior are labeled for control of peachtree borer on peaches. Directed sprays should be applied uniformly to the trunk from the base to the lower limbs. Thoroughly wet the bark. Do not allow Lorsban sprays to contact fruit foliage. Asana XL, while Warrior and Lorsban have 14 day preharvest intervals Asana XL, Warrior, and Lorsban are RESTRICTED USE insecticides.

Pheromone Trapping

Pheromone trapping uses chemical lures to attract male moths. These lures are synthetic copies of the chemicals female moths use to attract the mates. Moth captures in pheromone traps alert growers to pest activity and aid timing of insecticide sprays. 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 tree at eye level, usually one for each ten acres of trees (minimum of two traps per orchard) in commercial orchards. For a list of source of the various types of pheromone traps, see ENT-54, Vendors of Microbial and Botanical Insecticides and Insect Monitoring Devices.

Moth activity can occur anytime between mid-June and early August. In order to detect the first activity, traps should be hung in tree well in advance of the anticipated flight. Usually this means hanging traps shortly after petal-fall. Trap lures need to be replaced once a month. Traps bottoms should be replaced when the stick surface becomes clogged with other debris.

Proper identification of the moths captured in the trap is essential. There are many other moths which may wander into the trap, even other clear wing moths, such as the lilac borer or dogwood borer. Check the description of the male peachtree borers above. The lilac borer has red and black antennae, yellow and red legs, and the front wings are opaque black. The dogwood borer has thin yellow abdominal bars on the abdomen similar to the male peachtree borer, but the tips of the front wings have a broad black tips.

Mating Disruption

Mating disruption relies on confusion to prevent peachtree borers from mating. Male peachtree borer moths normally 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. Males are overwhelmed by the amount of pheromone and become desensitized to it. The result is that unfertilized moths are not able to lay viable eggs. Unlike other methods, peachtree borer moths are not killed with this technique. This technique is most successful in blocks of at least 5 acres and where initial populations of peachtree borer moth are low. There may be some damage along rows boarder woods or other areas that may be sources of already mated females. Keep in mind that mating disruption for peachtree borer will not control other insects that are normally controlled with cover sprays (plum curculio for example). Pheromone traps are used to ensure that the technique is working properly, as the male moths should not be able to locate the traps.

Worming Trees May be an Alternative

Before the development of chemicals for controlling peachtree borers, producers relied on digging the borers out of the bark by hand. This is still an alternative for backyard gardeners in the fall. Dirt should be removed from around the base of the tree to a depth of 4 to 5 inches. Care should be taken not to cut the sound bark more than necessary, and cutting should be done vertically. Carelessness may result in more damage to the tree than the damage that would have been caused by the borers! After the larvae have been located and removed, the dirt should be replaced around the base of the tree to the original level.

Revised: 11/19

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: R. Bessin, University of Kentucky Entomology

Peachtree Borer and Lesser Peachtree Borer

Descriptions of peachtree borers and lesser peachtree borers

Peachtree borer and lesser peachtree borer are caterpillars of clearwing moths (Lepidoptera: Sesiidae). Caterpillars are white to cream colored, wrinkled and have a brown head.

Life cycles of peachtree borers and lesser peachtree borers

Winter is spent as a larva under the bark in the cambium layer. Adult moths of the lesser peachtree borer emerge from late May through September, while peachtree borers emerge from mid–June to early September. Egg laying begins soon after emergence and mating and larvae tunnel into the bark to feed until the following summer.

The lesser peachtree borer only establishes in previously wounded bark, including pruning cuts, cankers and previously injured areas. Eggs of the peachtree borer are deposited around the bases of the trees or on the trunks.

Damage caused by peachtree borers and lesser peachtree borers

Larvae live just under the bark of the tree where they feed on the cambium, the inner bark of the tree. Larvae feeding in the trunk or branches cause girdling that can result in reduce yield, limb dieback or death of the tree.

Feeding Location:

Peachtree borers live and feed in the trunk of the tree from a few inches above to 6 inches below the soil line.

Lesser peachtree borers will be found feeding in wounded or injured portions of the trunk or larger branches. Exuded gum mixed with sawdust like frass forms at feeding sites. Lesser peachtree borer can only attack areas injured by pruning cuts, cankers or other insects.

Management of peachtree borers and lesser peachtree borers

Maintain tree vigor. Keep trees in a good healthy growing condition by mulching the root zone, watering as needed, and proper fertilization and pruning.

Spray insecticides. Sprays applied thoroughly to trunk and branches during the adult moth egg laying period will prevent further borer damage but will not cure damage and infestations already inside the tree. Sprays specifically for peachtree borer usually begin about June 1 and are repeated every 3 weeks for 3 or 4 additional sprays. Pheromone traps are available to monitor the emergence of adult moths and are used to time sprays.

Mechanical Control. Occasional borers can be surgically removed by carefully cutting larvae out of infested, bleeding trunks.

Do you live in Iowa and have an insect you would like identified?

The Iowa State University Plant & Insect Diagnostic Clinic will identify your insect, provide information on what it eats, life cycle, and if it is a pest the best ways to manage them. Please see our website for current forms, fees, and instructions on preserving and mailing insects.

Contact information for each states diagnostic laboratory for U.S. residents. If you live outside of Iowa please do not submit a sample without contacting the Plant & Insect Diagnostic Clinic.

Citrus Tree Borer

  • Problem Solver
    • Products
        • Pest Products
          • General Bug Control
          • Insect Guard
          • Fumigators
          • Non-Toxic Traps
          • Ants
          • Bed Bugs
          • Borer
          • Carpet Beetle
          • Cats and Dogs
          • Cluster Flies
          • Cockroaches
          • Fleas
          • Flies/Mosquitoes
          • Moths/Beetles
          • Possums
          • Rodents
          • Spiders
          • Wasps
        • Garden Products
          • Weed Weapon
          • LawnPro
          • Plant Health
          • Gro-Sure
          • Houseplant
          • Fertilisers
          • Organic
          • Garden Aids
      • Houseplant Products
      • Lawn Products
      • Cleaning Products
    • Problems
        • Home Pest Problems
          • General Bugs
          • Ants
          • Bed Bugs
          • Borer
          • Carpet Beetle/Moths
          • Cockroaches
          • Fleas
          • Flies/Mosquitoes
          • Mites
          • Rodents
          • Spiders
          • Stored Product Insects
          • Wasps
          • Other Pests
        • Garden Problems
          • Disease
          • Growing
          • Houseplant
          • Lawn
          • Pests
          • Weeds
        • Lawn Problems
          • Growing
          • Lawn Disease
          • Lawn Pests
          • Lawn Weeds
        • Cleaning Problems
          • Biological Marks
          • Dirt Marks
          • Surface Material
    • Advice
        • Pest Advice
        • Garden Advice
        • Houseplant Advice
        • Outdoor Cleaning Advice
    • Store Locator
      • Stockists
  • My Kiwicare
    • About Kiwicare
      • Certificates
      • David Brittain – Author and home pest and gardening expert at Kiwicare AHM Group
  • Personal Guarantee
  • Contact Us
  • Stockist Login
  • Privacy Policy

Synanthedon exitiosa

The Greater Peachtree Borer is also known as the Clearwing Peachtree borer. They will attack plum, prune, cherry, almond, apricot, and nectarine trees but they prefer peaches. It is a native North American pest that can seriously damage its host plants. The adult form is a clear winged moth with a 1¼” wingspan. The females are a dark, steel blue with a wide orange band and opaque front wings. The males are also steel blue, but they have several yellow bands, both pairs of their wings are clear, and are slightly smaller than the females.

Life Cycle & Appearance

Female Peachtree Borers lay their eggs on the tree trunks or at the base of the tree and lay 500-600 eggs on average. Upon hatching, the larvae bore just beneath the bark near the ground level and into the roots to feed on growing tissue and inner bark. Larvae are the damaging life stage of the Peachtree Borer and are reddish-brown with pale to white segments that give them a ringed appearance. Their head and thorax are dark brown to gray. Mature larvae can grow up to 12 mm long and undergo a pupal stage that lasts roughly 28 days. Once they pupate, the adult Peachtree Borer moths begin to emerge and mate in April or May and continue to do so through September.

Damage Symptoms

Young trees are particularly susceptible to borers because they can damage large portions of smaller trees’ vascular tissue. Since the larvae feed in galleries (tunnels bored in the wood), accumulating gum, frass and bark are generally the first signs of an infestation as the detritus is pushed out of the galleries. Older trees tend to be more resistant to borer damage, but many exhibit yellowing of the foliage, stunted growth, partial die-back and/or loss of vigor and fruit production.

Controlling Peachtree Borers

  • Once dormant season pruning is complete, spray trees with Horticultural Oil.
  • Apply Tree Paint early in the season to the trunks of susceptible trees to reduce bark cracking, sun stress and suitable egg-laying areas.
  • Pheromone traps can be used as effective monitoring tools, but should not be relied upon to control a Peachtree Borer population.
  • Applications of Beneficial Nematodes (Steinernema carpocapsae and Heterorhabditis bacteriophora) have shown positive results in controlling Peachtree Borer larvae when applied directly to bark cracks with frass buildup.
  • When adults are present, release Trichogramma Moth Egg Parasites to control egg populations.
  • Insecticide applications to the tree trunk can be made to kill the eggs already present. Neem Oil, Pyrethrins and Azadirachtin are all suitable for controlling peachtree borers. Application location should be isolated to where damage or pests are seen to limit effects on the environment.
  • Mating disruption using pheromone dispensers has proven to be the most effective borer damage control.
  • Overall tree health is paramount in fending off pest insect populations, so fertilizing, watering and environmental conditions should be monitored continuously.
  • Clear ground cover and vegetation away from the base of the tree as both will provide additional protection for eggs and larvae.

Photo courtesy of Clemson University Department of Entomology, Soils & Plant Sciences, Cooperative Extension Service.

How to Manage Pests

UC Pest Management Guidelines

| More pests | All crops | About guidelines |

Peach

Peachtree Borer

Scientific name: Synanthedon exitiosa

(Reviewed 4/10, updated 4/10, pesticides updated 9/15, corrected 1/19)

In this Guideline:

  • Description of the pest
  • Damage
  • Management
  • Publication
  • Glossary

DESCRIPTION OF THE PEST

Gum exuding from around the base of the trunk is evidence of peachtree borer. Larvae of the peachtree borer, found mainly in coastal areas and in the northern San Joaquin Valley, are white with brown heads. Adults are clear-winged moths with blue-black bodies having yellow or orange bands across the abdomen. The adult peachtree borer may be found from May to September, with larvae present in the tree the rest of the year. There is only one generation each year.

DAMAGE

This wood-boring insect can successfully attack healthy trees. The larval stage bores into the crown and trunk of the tree and mines the cambial layer. If this occurs for several years, the tree may eventually become girdled and die.

MANAGEMENT

Apply insecticides when adults emerge in May and again 6 weeks later. Pheromone traps are available to monitor adult emergence. Insecticides are not likely to kill larvae within the tree but will protect against reinfestation as emerged adults lay new eggs on the trunk. Results may not be evident until the following season.

Common name Amount to use** REI‡ PHI‡
(Example trade name) (conc.) (dilute)
(hours) (days)
UPDATED: 9/15
The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide’s properties and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
A. ESFENVALERATE*
(Asana XL) 4.8–14.5 fl oz 2–5.8 fl oz 12 14
MODE-OF-ACTION GROUP NUMBER1: 3A
COMMENTS: Apply as a directed trunk and scaffold limb spray. Thorough coverage of trunk and scaffolds is required. In dilute application, do not apply more than 200 gal water/acre at the 5.8 fl oz rate. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.
** For dilute applications, rate is per 100 gal water to be applied in 300-500 gal water/acre, according to label; for concentrate applications, use 80-100 gal water/acre, or lower if the label allows.
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
# Acceptable for use on organically grown produce.
1 Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

PUBLICATION

UC IPM Pest Management Guidelines: Peach
UC ANR Publication 3454

Insects and Mites

J. K. Hasey, UC Cooperative Extension, Sutter and Yuba counties
K. R. Day, UC Cooperative Extension, Tulare County
K.Tollerup, UC IPM Program, Kearney Agricultural Center, Parlier

Acknowledgment for contributions to the Insects and Mites:

W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
C. Pickel, UC IPM Program, Sutter and Yuba counties
R. E. Rice, Kearney Agricultural Center, Parlier

Top of page

Cherry-Peachtree borer

Synanthedon exitiosa

Pest description and crop damage Peachtree borer is a clearwing moth native to North America and common in the Northwest. The adult is a metallic blue-black. The male moth may have bands of light yellow scales on the abdomen, and resembles a wasp. The female has an orange band around the abdomen. Full-grown larvae are one inch long and whitish with a brown head. Larvae burrow into the bark of the crown and feed on the cambium. Feeding is restricted to an area a few inches above and below the soil line. Young trees can be girdled completely and killed. Older trees are rarely girdled, but the feeding reduces vigor and makes them vulnerable to other pests and diseases. Infested trees bleed frass-infested gum during the growing season.

Biology and life history The borer overwinters as a larva on or under the tree bark, usually below ground. As temperatures rise above 50°F in the spring, the larva resumes feeding on the tissues under the bark. At maturity in May and June, the larva pupates. Adult moths emerge beginning in June and continue through September. Eggs are laid quickly after mating, and the young larvae hatch after 8 to 10 days and bore immediately into the base of the tree. Larvae in the bark above the soil line usually do not survive the winter in cold areas.

Pest monitoring This insect can do substantial damage if not controlled-one larva can kill a small tree. Therefore, the finding of a single larva justifies action in a small home orchard.

Management-biological control

Several wasp species are parasitic on the larvae or pupae of the borer.

Management-cultural control

Protect the base of the tree from larval entry by placing a cone around it before egg laying begins. Light metal or flexible plastic works. The cone should be pushed 1 to 2 inches into the soil and should fit snugly around the trunk at the top to prevent the tiny larvae from getting beneath it. Budding tape or other flexible material will help seal the top.

Alternatively, if there are only one or a few peach trees in a home orchard, it is quicker and cheaper to control this insect by worming. Use a pocket knife or some pointed instrument to remove dirt around the tree and dig out the larvae.

Management-chemical control: HOME USE

  • carbaryl
  • gamma-cyhalothrin
  • kaolin clay (Surround at Home)-Repels some insect pests when applied as a spray to leaves, stems, and fruit. OMRI-listed for organic use.
  • lambda-cyhalothrin
  • permethrin
  • pyrethrins-Some formulations are OMRI-listed for organic use.

Management-chemical control: COMMERCIAL USE

Dormant-season and delayed-dormant sprays

Direct sprays to the trunks and bases of trees. A full dilute drenching spray gives best control.

  • chlorpyrifos (Lorsban 75 WG) at 2.0 to 2.67 lb/a. REI 4 days. May be mixed with horticultural mineral oil (rates vary; see product label). Do not exceed one application of chlorpyrifos as a dormant or delayed-dormant per season. Avoid contact with foliage in sweet cherries as premature leaf drop may result. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.

Growing-season sprays

Direct sprays to the trunks and bases of trees. A full dilute drenching spray gives best control.

  • esfenvalerate (Asana XL) at 4.8 to 14.5 fl oz/a. REI 12 hr. PHI 14 days. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
  • lambda-cyhalothrin (Warrior II) at 1.28 to 2.56 fl oz/a. REI 24 hr. PHI 14 days. May disrupt beneficial mite populations. Extremely toxic to fish; avoid spray drift and surface runoff.
  • permethrin (Pounce 25DF) at 6.4 to 12.8 oz/a. REI 12 hr. PHI 3 days. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.

Leave a Reply

Your email address will not be published. Required fields are marked *