- How to get rid of scales on Zamia, thrips on gardenias
- Gardenias and Spider Mites, Yikes!
- Ask Grumpy Gardener: What to Do When Your Gardenia Leaves Turn Black
- Kill the Suckers, Prevent the Mold
- Other Plants to Watch
- Gardenia Insects & Related Pests
- Insect Pests
- Related Pests
- Master Gardener – Whiteflies are one thing gardenias fall prey to
- Gardenia Bugs – How To Control And Eliminate Gardenia Insects
- Common Gardenia Insects
- Common Insect Related Gardenia Diseases
How to get rid of scales on Zamia, thrips on gardenias
Identify that Zamia and its scale first
Q: Will neem oil work in controlling scale on cycads? Our Zamia is totally covered. Is there a better way to control the scale?
A: Neem oil works in controlling scale quite well. However, the size and concentration of the infestation along with the positive identification of the insect and plant need to be taken into consideration when developing a control strategy.
Florida red scale — an armored scale that looks like a pimple, black with a reddish top that doesn’t move as an adult — and mealybugs — small ⅛-inch greyish-yellow critters covered with white powdery wax, which are mobile about the leaf — are Zamia’s two primary scales.
If your problem plant is Zamia integrifolia (floridana), our native coontie, cut the foliage down to the ground and let them start over. It sounds drastic, but it’s your only recourse. Then continue to monitor the new foliage for any scale. The more shade they are in, the worse scale problems can become.
If your problem plant is Zamia furfuracea, cardboard plant, remove the most infected fronds and spray on 10- to 14-day cycles with neem oil, following label directions, until the problem is under control, then monitor and act quickly if the tiny rascals return.
Spray those thrips, but flowers may become damaged
Q: We have a gardenia bush and when it flowers, there are little black bugs all over the flowers. What are they, and how do we get rid of them? Earl Little, New Port Richey
A: The pesky little critters in and on your gardenia flowers are called thrips. The tiny black ⅛-inch insects feed by rasping plant parts, flowers in your case, then lapping up the plant sap. This type of feeding causes flowers to shatter, lessening their useful life. For control, there are many products that contain synthetic pyrethroids as an active ingredient and all end in “thrin”: bifenthrin, cyfluthrin, lambda cyhalothrin, permethrin, etc. Some of the brand names include: Ortho Bug-B-Gon Max, Bayer Advanced Rose & Flower, Bayer Advanced Garden Power Force, Spectracide Trazicide Once & Done, Spectracide Immunox Plus, Southern Ag Permetrol Rose Flower, Fruit & Vegetables and many more. Some are concentrates and others are ready-to-use. Spray, according to label directions every seven to 10 days. Oil sprays damage the flowers.
Never fear: That corkiness is normal in adolescence
Q: This is our sweetgum. It is just now leafing and has this funky growth. Can you tell me if I need to administer first aid? We love this tree and would not want to lose it. Linda Baker
A: Not to worry, no Band-Aid or surgery will be needed. Both sweetgum, Liquidambar styraciflua, and winged elm, Ulmus alata, put out corky projections on their twigs and stems as part of their bark. The fluting on sweetgum doesn’t usually appear for the first few years, so when it appears, it looks a tad scary. On the other hand, winged elm, by its name, gives the new owner a heads-up. As your sweetgum ages, it will lose this juvenile characteristic, but the elm is corky for life.
Here’s how to root a cutting
Q: I recently obtained a kapok blossom and it was on a piece of tree branch about 6 inches long. I put the branch in a small amount of water outside. This was about two weeks ago. The branch has 2 green sprouts now growing out of the part that is not in the water. There are no roots showing on the bottom of the branch in the water. I would really like to grow this into a tree. What should I do next? Can I put it in a pot in potting soil without roots? I hope you have an answer. Donald Wiley
A: The easiest way to root a cutting is to take a 1 gallon plastic bag, fill it ⅓ full with a moistened (not wet) peat-based mix such as FoxFarm Light Warrior Soiless Mix, Hoffman All Purpose Potting Mix, Fafard, Promix, Jiffymix or Miracle Gro Potting Mix; make a fresh cut at the bottom of the stem (with sharp clippers); apply a rooting enhancer such as Rootone, Hormex, Clonex, Hormodin or Dip-N-Grow on the end of your cutting; place into the bagged moistened peat mix approximately 2 inches deep; close the bag ¾ of the way; and place in bright light. Check periodically for any heat buildup, and move accordingly. In four to six weeks you should have sufficient roots to upgrade.
Pot it into a 4- to 6-inch container with some of the same mix to grow on. You can use your mini greenhouse to root just about any plant with stems, 4- to 6-inch cuttings of “green wood” (new spring growth) forms roots the quickest.
Gardenias and Spider Mites, Yikes!
While gardenias don’t like to be saturated with water, a constant supply of moisture ensures the plant retains it blossoms and remains healthy. To tell if your gardenia needs water, stick your finger into the soil. If it feels dry, water it. If the soil is so soggy it feels squishy, you’re watering it too much.
Speaking of soil, your gardenia will need rich, well-drained soil. Try an organic potting soil for the healthiest plants. The soil needs to be a bit acidic for best results. Get a soil tester kit and check it. The best soil for gardenias should have a pH between 5 and 6.If the soil is lacking in acidity, there are a few things you can do. Some gardeners swear by adding pickle juice to their gardenia soil. Vinegar may work just as well, just be sure it is diluted in water because vinegar can kill plants and is often used as a natural herbicide to get rid of weeds. Dilute at a ratio of one cup vinegar or pickle juice to one gallon of water and use it to water your gardenias once a month. You can also use a product called Miracid to keep the soil at the right acidity for your acid-loving houseplants.
One thing to keep in mind if you have just purchased your gardenia is that is probably in the correct soil already. It isn’t a good idea to repot a new gardenia because it will probably go into shock and drop all its buds. Gardenias do best if they are slightly root-bound so there is really no need to repot it unless you see roots coming out of the top of the plant. If you don’t like the pot it is in, just place it inside a slightly larger, decorative pot.
Indoor gardenias need the same or similar fertilizer as their outdoor cousins. Use a fertilizer specially formulated for gardenias. Any fertilizer used for plants that like acidic soil also works well. Use fertilizer according to the label directions.
Deadhead or remove spent blossoms. Don’t be afraid to prune your gardenia as necessary. Pruning encourages healthy new growth and blossoms. For most gardenia varieties, pruning should be done right after the plant is done blooming. If you wait too long to prune, it will not bloom the next year.
Don’t Give Up On Gardenias
Don’t give up on gardenias if your first plants fail to thrive or die. Gardenias can be tricky. For some people, growing the perfect gardenia becomes an all-consuming passion. The quest for the perfect scented creamy-white blossom makes growing gardenias a rewarding hobby for the amateur horticulturist.
OK Onto Spider Mites
If your gardenia isn’t provided the best environment, it can weaken the plant and make it an easy target for spider mites. These small creatures suck nutrients and juices from the leaves of plants, causing discoloration and yellow blotches. They can form a spider-like silk web on the underside of leaves for purposes of protection and, if left unchecked, a web over the entire plant, severely stunting growth or killing it. Spider mites can float along with summer wind currents or be carried by garden visitors such as raccoons, pets, or infected plant material. To spot these mites, first look at the plant leaves and if they appear to have a rash of tiny yellow pinpricks all over the surface, any discoloration coupled with unexpected leaf drop, suspect this pest as the cause. The tiny mites will be visible to anyone with good eyesight, but using a magnifying glass also helps. These are some nasty bugs whose populations can increase dramatically if not thwarted! These insects are the true survivors of the insect world.
Ask Grumpy Gardener: What to Do When Your Gardenia Leaves Turn Black
By Steve Bender
“My poor gardenias are suffering!” writes faithful reader, Sheri Chamblee. “The leaves are black. I tried rubbing the black off, but the black remains. What else can I do?”
The answer, of course, is to ask Grumpy, your font of gardening wisdom.
The black stuff on the leaves is a fungus called sooty mold. It doesn’t attack plants directly. Instead, it grows on the sticky honeydew secreted by sucking insects feeding on the plant. So inspect the foliage carefully, both top and bottom surfaces. Do you see anything like this?
White flies. Photo: johnston.ces.ncsu.edu
Congrats. Your plant is infested with white flies — very common, very destructive, and very hard to control once established.
Or do you see little bumps on the leaves and stems that look like this?
Scales. Photo: http://www.yates.com.au
Cowabunga! Your plant is infested with scales. There are lots of different kinds, but the little suckers all do the same thing. Suck plant juices and damage and kill plants.
Kill the Suckers, Prevent the Mold
If you kill the sucking insects and prevent their return, the mold goes away. I’ll give you two ways to do this.
1. Apply Bayer Advanced Tree & Shrub Protect & Feed according to label directions. This product contains a systemic insecticide that’s absorbed by the plant. When insects suck the sap, they suck in the systemic and it kills them. This product works for months.
2. If you prefer a natural pesticide, spray all leaf and stem surfaces according to label directions with an all-season horticultural oil. This product kills insects, their larvae, and their eggs on contact, but it doesn’t keep them from returning. So you’ll have to spray multiple times.
Other Plants to Watch
Gardenia isn’t the only plant targeted by sucking insects and sooty mold. You’ll often find both on crepe myrtle, camellia, citrus, holly, and tulip poplar.
Don’t fall asleep at the wheel. Kill the bugs before the mold takes hold!
Gardenia Insects & Related Pests
With their wonderfully fragrant blossoms and lustrous, dark green leaves, gardenias (Gardenia angusta, previously known as G. jasminoides) are popular shrubs with many southern gardeners. Their positive qualities compensate to a large extent for the fact that gardenias are somewhat high-maintenance plants with fairly specific cultural requirements. To learn more about growing healthy gardenias, see HGIC 1065, Gardenia. In addition to problems resulting from improper growing conditions, gardenias are also susceptible to several diseases, insect pests, and other problems. For information on diseases and other problems that affect gardenias, see HGIC 2058, Gardenia Diseases & Other Problems.
Whitefly adults (Dialeurodes citri) on underside of gardenia leaf.
J. McLeod Scott, ©2010 HGIC, Clemson Extension
Whiteflies: Whiteflies are not true flies, but are more closely related to scale insects, mealybugs, and aphids. They are very small – about 1/10 to 1/16 inch long. They have a powdery white appearance and resemble tiny moths. When at rest, the wings are held at an angle, roof-like over the body. The immature stage is scale-like and does not move. When plants that are infested with whiteflies are disturbed, the whiteflies flutter around briefly before settling again.
Both adults and immature forms of the citrus whitefly (Dialeurodes citri) feed by sucking plant sap. The damage that they cause is similar to that caused by aphids. The infested plant may be stunted. Leaves turn yellow and die. Like aphids, whiteflies excrete honeydew, which makes leaves shiny and sticky and encourages the growth of sooty mold fungi. See Sooty Mold section in HGIC 2058, Gardenia Diseases & Other Problems for detailed information.
Control: Insecticidal soap or horticultural oil sprays are effective against whiteflies, but the plant must be sprayed thoroughly so that the soap or oil contacts the insects on the underside of leaves. Repeat spray three times at 5-7 day intervals. Foliar injury from soaps and oils may occur on plants under drought stress. Water the plants well the day before spraying. Only apply horticultural oils or insecticidal soaps if temperatures are below 90 °F, and apply very late in the day to prevent foliar injury. If stronger insecticides become necessary, products containing pyrethrin, bifenthrin, cyfluthrin, permethrin, esfenvalerate, or acephate, can be used. Acephate is a foliar systemic insecticide and may provide better control than the other contact spray insecticides. Soil-applied insecticides, such as imidacloprid or dinotefuran, can give season-long control of whiteflies. These are applied as a soil drench or as granules, which are watered into the soil. See Table 1 for products that contain these insecticides.
Scale Insects: Various scale insects feed on gardenias, including the soft scales – Japanese wax scale (Ceroplastes japonicus) and cottony cushion scale (Icerya purchasi); and the armored scales – tea (Fiorinia theae), greedy (Hemiberlesia rapax), and oleander scales (Aspidiotus nerii).
Japanese wax scale (Ceroplastes japonicus), a soft scale that attacks gardenias, is typically found on twigs and branches.
Giuseppina Pellizzari, Faculty of Agriculture, Dept. of Entomology, www.insectimages.org
Cottony cushion scale, a soft scale (Icerya purchasi).
Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org
Tea scale (Fiorinia theae) is an armored scale that feeds on gardenias. This scale is found mainly on the lower surfaces of leaves.
Clemson University – USDA Cooperative Extension Slide Series, www.insectimages.org
Scales are unusual insects in appearance, and as a result are sometimes misidentified by gardeners either as parts of the plant itself or as disease organisms rather than insects. Adult female scales are small and immobile, with no visible legs. They secrete a waxy coat that varies significantly in shape and color depending on the species. Adult males tend to be very small and have wings, which allow them to fly so they can locate females.
Scales feed on plants by piercing the leaf, stem or branch with their mouthparts and sucking sap. Their feeding can weaken or kill branches. Heavily infested gardenias are often stunted with small flowers and leaves. Leaves may yellow and drop early. Like aphids, soft scales excrete honeydew. Armored scales do not excrete honeydew. The growth of the sooty mold fungus on honeydew results in leaves that are covered in dark fungal growth. See the Sooty Mold section in HGIC 2058, Gardenia Diseases & Other Problems for detailed information.
Adult scales are relatively well protected from traditional insecticides by their waxy covering. Their immature forms, called crawlers, are susceptible, however.
Control: A combination of various natural enemies, including ladybird beetles (ladybugs) and parasitic wasps, usually keep scale insects under control. With light infestations, scale can be scraped off or infested branches can be removed and destroyed.
Horticultural oil is an excellent, proven product for scale control. It alone will control all stages of armored scales on gardenias and other shrubs. Horticultural oil is safe to use and is an especially good choice for sensitive areas, such as where people are present soon after treatment. Because of the short residual, oil sprays help to conserve beneficial insect species. Horticultural oil sprays kill by suffocation. Spray in early spring to kill any overwintering adults, crawlers or eggs. Apply these spray applications again when new leaves start to expand in the spring. At least two more spring applications are needed at five- to six-week intervals. Spray the plants thoroughly, so that the oil sprays drip or “run off” from the upper and under sides of leaves, branches, and trunk. It is best to spray horticultural oil when the temperatures are above 45 and below 90 degrees, and to spray during the early evening to slow the drying of the oil spray application.
Follow label directions for mixing rates with water. Typically, a 1 or 2% mixture of horticultural oil is applied. On mature foliage, apply a 2% mixture spray (5 tablespoons of oil per gallon of water). During the spring, as new tender growth appears, apply 1% mixture spray (2½ tablespoons per gallon of water).
Insecticidal soap sprays work well to control soft scale adults and crawler. Like with a horticultural oil spray, spray soaps when temperatures are below 90 °F, and spray in the evening to reduce the drying time of the spray. Spray the plants thoroughly, so that the oil sprays drip or “run off” from the upper and under sides of leaves, branches, and trunk. Follow label directions for mixing and use.
In terms of traditional insecticides, only the crawler stage is susceptible. Recommended insecticides for use against crawlers include the following: acephate, permethrin, lambda cyhalothrin, cyfluthrin, bifenthrin, and esfenvalerate. Apply these materials only when crawlers are present and repeat after 10 days.
Soil-applied insecticides can give season-long control of scale insects Dinotefuran can control both soft and armored scales. This treatment is applied as a soil drench or as granules, which are then watered into the soil. See Table 1 for products containing dinotefuran. As with all pesticides, read and follow all label instructions and precautions.
Both winged and wingless adults as well as immature green peach aphids (Myzus persicae) are present on a leaf. Green peach aphids infest a wide range of plants, including gardenias.
Whitney Cranshaw, Colorado State University, www.forestryimages.org
Aphids: These small (about 1/8 inch long), soft-bodied, pear-shaped insects are sometimes referred to as plant lice. They vary in color according to species and can be shades of green, yellow, pink, or black. Both the green peach aphid (Myzus persicae) and the melon (or cotton) aphid (Aphis gossypii) feed on gardenias. They are usually found in clusters on new growth of buds, leaves and stems.
Aphids feed on plant sap with their piercing-sucking mouthparts. A low population of aphids does little damage to a gardenia; however, aphids reproduce very rapidly and can quickly reach numbers that cause damage. Their feeding results in distorted or curled and stunted growth. Heavy infestations can reduce the number and quality of blooms. As they feed, aphids excrete honeydew, a sugary substance that often attracts ants. In addition, honeydew supports the growth of unsightly, dark-colored sooty mold fungi on the leaves. See the Sooty Mold section in HGIC 2058, Gardenia Diseases & Other Problems for details.
Control: Aphids have several natural enemies, including parasitic wasps, ladybird beetles (ladybugs) and larvae, and green lacewing adults and larvae. Their natural enemies tend to keep aphid populations under control except in cool weather. Ants are sometimes present with aphid infestations and will protect them from their natural enemies. If ants are present, they should be controlled.
Aphids can be hosed off with a strong stream of water directed above and below the leaves. Spraying with water should be repeated frequently as needed, focusing in particular on new growth. Gardenias can also be sprayed with insecticidal soap or horticultural oil to control aphids. Insecticidal soap or horticultural oil must be sprayed onto the aphids to be effective. Repeat spray three times at 5-7 day intervals. Foliar injury from soaps and oils may occur on plants under drought stress. Water the plants well the day before spraying. Only apply horticultural oils or insecticidal soaps if temperatures are below 90 °F, and apply very late in the day to prevent foliar injury.
While higher toxicity insecticides are available, it is important to note that aphids are very difficult to control because they multiply so rapidly. Leaving even one aphid alive can quickly result in a population explosion. In addition, these insecticides kill the natural enemies of aphids.
If stronger insecticides are deemed necessary, the following are available in homeowner-size packaging. Sprays containing acephate, bifenthrin, cyfluthrin, permethrin, lambda cyhalothrin, esfenvalerate, malathion, neem oil, or pyrethrin will control aphids. Soil drenches or granular applications of imidacloprid or dinotefuran will control aphids and last longer within the plant to prevent future infestations. See Table 1 for products containing these insecticides.
Thrips: Flower thrips (Frankliniella tritici), Western flower thrips (F. occidentalis) and various other thrips species are pests of gardenia flowers. Thrips are slender, dark-colored insects, with fringed wings. Adults are less than 1/16 inch in length. To see these fast-moving pests, you need a magnifying lens. Thrips are typically found on leaves and between flower petals. Both adults and nymphs (immature insect stages that resemble the adult, but are smaller) feed by scraping surface cells to suck plant sap.
When thrips feed on flower buds, the flower may die without opening. With a light infestation, their feeding causes leaves to have silvery speckles or streaks. With severe infestations, flowers are stunted and distorted and may turn brown and die.
Thrips feed also on expanding leaves, which creates purplish red spots on the undersurfaces and causes foliage to severely curl or roll, then drop prematurely.
As a result of their small size, thrips are difficult to detect before damage is obvious. To sample for thrips on gardenia flowers, hold a sheet of stiff white paper under injured flowers, and then tap the flower. Examine the paper in bright sunlight. Any thrips present will move around on the paper. In addition, blowing lightly into the blooms causes thrips to move around, making them easier to see.
Control: Several naturally-occurring enemies feed on thrips. To avoid killing these beneficial insects which reduce thrips populations, insecticides should be avoided as much as possible. Grass and weeds in the area should be kept mowed or removed when possible.
If it becomes essential to spray an insecticide, the following are available in homeowner-size packaging: bifenthrin, cyfluthrin, lambda cyhalothrin, permethrin, esfenvalerate, or spinosad. Spinosad and acephate are foliar, systemic spray insecticides that will better control thrips that are within flower buds than will contact insecticides. Spray when thrips are present and again in 7 to 10 days. Soil drenches or granular applications of dinotefuran or imidacloprid will give some thrips suppression. See Table 1 for specific products.
Two-spotted spider mites (Tetranychus urticae) on a leaf.
David Cappaert, Michigan State University, www.forestryimages.org
Spider Mites: Mites are not insects. They are more closely related to spiders, having eight legs as adults rather than six. Spider mites are extremely small (about 1/50-inch long) and are somewhat difficult to see on a plant without a magnifying lens. One way to make them easier to detect is to hold a piece of white paper under a branch and then tap the branch sharply. If still not visible, wipe your hand over the paper. If mites are present, red streaks will be seen.
Two-spotted spider mites (Tetranychus urticae) are pests on gardenias in South Carolina. While these mites may be present throughout the growing season, their populations tend to reach damaging numbers during hot, dry weather.
Mites have piercing-sucking mouthparts. They suck plant sap, typically feeding on the lower surface of a leaf. Early damage is seen as yellow or white speckling on the leaf’s upper surface. The shape of new leaves may be distorted as a result of their feeding. Fine webbing may be seen on the undersides of leaves. With severe infestations, webbing may cover both sides of leaves as well as branches. Webbing can collect dust and debris and makes the plant appear untidy.
Control: Both beneficial insects, such as lacewings and lady beetles, and predatory mites prey on spider mites. Predatory mites are about the same size as spider mites but can be distinguished from spider mites by their long legs and the speed with which they move. Several species of predatory mites, lacewings, and lady beetles are available commercially for use as biological control agents.
A strong spray of water is a non-chemical control option that removes eggs, larvae (six-legged immature stage), nymphs (eight-legged immature stage) and adult mites. Be sure to spray lower surfaces of leaves and repeat as needed. This method is most effective with light infestations as seen with early detection. An important advantage of this control method is that populations of natural pest enemies are not harmed.
Insecticidal soaps and horticultural oils are effective control options for spider mites and are essentially nontoxic to humans, wildlife, and pets, and only minimally toxic to beneficial predators. When using these products, good coverage is critical to ensure contact with the pest, and reapplication may be needed as determined by follow-up monitoring for the pest. Foliar injury from soaps and oils may occur on plants under drought stress. Water the plants well the day before spraying. Spray very late in the day, and do not spray with soaps or oils if the temperature exceeds 90 °F.
When growing gardenias, the use of broad-spectrum insecticides should be avoided as much as possible, as these products can kill off natural enemies that help keep spider mite populations in check. Also, avoid pesticides that claim to “suppress” mites as they tend to be weak miticides. When stronger chemical control is needed, the following insecticides/miticides are available in homeowner-size packaging: tau-fluvalinate or bifenthrin sprays. See Table 1 for products containing these insecticides.
Table 1. Insecticides for Gardenia Insect Pest Control.
|Pesticide Active Ingredient||Brand Names & Products|
|Acephate||Bonide Systemic Insect Control Concentrate|
|Bifenthrin||Ferti-lome Broad Spectrum Insecticide Concentrate
Hi-Yield Bug Blaster Bifenthrin 2.4 Concentrate
Ortho Bug-B-Gon Insect Killer for Lawns & Gardens Conc.; & RTS1
|Cyfluthrin||Bayer BioAdvanced Vegetable & Garden Insect Spray Concentrate|
|Dinotefuran||Gordon’s Zylam Liquid Systemic Insecticide (drench3)
Gordon’s Zylam 20SG Systemic Turf Insecticide (drench3)
Ortho Tree & Shrub Insect Control Ready to Use Granules (2%)
Valent Brand Safari 2G Insecticide (2%; granules)
Valent Safari 20SG Insecticide (drench3)
|Horticultural oil2||Bonide All Seasons Spray Oil Concentrate
Espoma Earth-tone Horticultural Oil Concentrate; & RTS1
Ferti-lome Horticultural Oil Spray Concentrate
Monterey Horticultural Oil Concentrate
Southern Ag ParaFine Horticultural Oil Concentrate
|Imidacloprid||Bayer BioAdvanced Garden 12 Month Tree & Shrub Insect Control Landscape Formula Concentrate (drench3)
Bonide Annual Tree & Shrub Insect Control w/ Systemaxx (drench3)
Ferti-lome Tree & Shrub Systemic Insect Drench3
Hi-Yield Systemic Insect Spray (drench3)
Monterey Once A Year Insect Control II (drench3)
|Insecticidal soap4||Bonide Multi-Purpose Insect Control Soap Concentrate
Espoma Earth-tone Insecticidal Soap Concentrate
Natural Guard Insecticidal Soap Concentrate
Safer Brand Insect Killing Soap Concentrate
Garden Safe Insecticidal Soap Insect Killer Concentrate
|Lambda or gamma cyhalothrin||Martin’s Cyonara Lawn & Garden Concentrate
Spectracide Triazicide Insect Killer for Lawns & Landscapes Conc.; & RTS1
|Malathion||Bonide Malathion 50% Insect Control
Gordon’s Malathion 50% Spray
Hi-Yield 55% Malathion Insect Spray
Martin’s Malathion 57% Concentrate
Ortho Max Malathion Insect Spray Concentrate
Spectracide Malathion Insect Spray Concentrate
Southern Ag Malathion 50% EC
Tiger Brand 55% Malathion
|Neem oil||Ferti-lome Rose, Flower & Vegetable Spray Concentrate
Garden Safe Fungicide 3 Concentrate
Garden Safe Neem Oil Extract Concentrate
Monterey 70% Neem Oil Fungicide/Insecticide/Miticide Concentrate
Natural Guard Neem Concentrate
Safer Brand Concern Garden Defense Multi-Purpose Spray Concentrate
Southern Ag Triple Action Neem Oil Concentrate
Bonide Neem Oil Concentrate
|Permethrin||Bonide Eight Insect Control Vegetable, Fruit & Flower Concentrate
Bonide Total Pest Control Outdoor Concentrate
Bonide Eight Yard & Garden RTS1
Hi-Yield Indoor/Outdoor Broad Use Insecticide Concentrate
Tiger Brand Super 10 Concentrate
|Pyrethrin||Bonide Garden Insect Spray Concentrate
Monterey Bug Buster-O
Monterey Pyganic Gardening
Southern Ag Natural Pyrethrin Concentrate
|Spinosad||Bonide Colorado Potato Beetle Beater Concentrate
Bonide Captain Jack’s Deadbug Brew Concentrate; & RTS1
Dow Conserve SC Turf & Ornamental Concentrate
Ferti-lome Borer, Bagworm & Leafminer Spray Concentrate
Monterey Garden Insect Spray Concentrate
Natural Guard Landscape & Garden Insecticide RTS1
Ortho Insect Killer Tree & Shrub Concentrate
Southern Ag Conserve Naturalyte Insect Control Concentrate
|Tau-Fluvalinate||Bayer Advanced 3-in-1 Insect, Disease & Mite Control Conc.; & RTS1|
| 1RTS = Ready to Spray (hose-end applicator)
2Never apply a horticultural oil spray within 2 weeks of a sulfur spray, and do not apply oils when the temperature is above 90 °F or to drought-stressed plants. Spray late in the day.
3Drench = Add to water and pour around base of plant.
4Gardenias are sensitive to some insecticidal soaps. Check product label to make sure that it is listed as safe for gardenias. Do not apply soaps when the temperature is above 90 °F or to drought-stressed plants. Spray late in the day.
With all pesticides, read and follow all label instructions and precautions.
Note: Pollinating insects, such as honey bees and bumblebees, can be adversely affected by the use of pesticides. Avoid the use of spray pesticides (both insecticides and fungicides), as well as soil-applied, systemic insecticides unless absolutely necessary. If spraying is required, always spray late in the evening to reduce the direct impact on pollinating insects. Always employ cultural controls first, then use less toxic alternative sprays for the control of insect pests and diseases. For example, sprays with insecticidal soap, horticultural oil, neem oil extract, spinosad, Bacillus thuringiensis (B.t.), or botanical oils can help control many small insect pests and mites that affect garden and landscape plants. Neem oil extract or botanical oil sprays may also reduce plant damage by repelling many insect pests. If soil applied insecticides are used, make applications immediately after flowering to reduce the amount of insecticide exposure to pollinating insects. For more information, contact the Clemson Home & Garden Information Center.
Master Gardener – Whiteflies are one thing gardenias fall prey to
Almost every yard in the South has at least one gardenia.
Almost every yard in the South has at least one gardenia. Planted by generations of gardeners for their exotically fragrant white blossoms, these tough evergreen shrubs are salt tolerant, drought tolerant and deer resistant. One thing they cannot resist, however, is the tiny whitefly. These petite pests cause gardenia leaves to turn yellow and plants to appear dark or sooty.
If this describes the gardenia in your yard, now is the time to check for whitefly and determine if treatment is needed.
Adult whiteflies look like tiny white moths and are about ¹/10 of an inch in length. Like many pests, they are most often found on the backside of leaves.
When infested plants are disturbed, whiteflies will flutter around for a few minutes and then resettle on the plant. Giving a bush a quick shake is an easy way to scout for whiteflies at this time of year.
In reality, whiteflies are neither flies nor moths, but are most closely related to mealybugs, aphids and scale insects. They feed on plant sap with needle-like mouthparts.
Plants that are heavily infested with whitefly often have lots of yellow leaves and clouds of whitefly emerge when the plant is disturbed. In addition, like their scale, aphid and mealybug relatives, whitefly secrete honeydew, a sticky sweet substance that attracts ants and wasps. Black sooty mold, a harmless fungus that grows on the honeydew, can cover whitefly-infested plants, causing the leaves and stems to appear dark and sooty.
There are several types of whitefly in the South. Some feed on vegetables. Others are more common in greenhouses and on houseplants. The type of whitefly found on gardenia is known as the citrus whitefly. While citrus whitefly has been reported to feed on 38 different types of plants, they are almost always found only on gardenia or citrus trees in our area.
If your gardenia has lots of yellow leaves, or if the leaves and stems look dark and sooty, you should check for whitefly. Recently emerged adult whitefly will be easily visible on the new growth. If you look on the back of older leaves, you will likely find both adult and immature whitefly. In their immature stage, whitefly resemble their scale relatives, looking like light orange, round, flat discs stuck to the back of the leaf.
Whiteflies produce several generations each season. If you have them on your gardenia bush now, they will likely persist all summer and into future seasons.
On some bushes, whiteflies never seem to get out of hand. This is because their populations are kept in check by beneficial insects, including ladybugs, lacewings and parasitic wasps.
If you find whitefly on your gardenia but it is otherwise healthy with lots of clean, green leaves, you probably do not need to treat. In fact, applying pesticides can disrupt the balance between beneficial and pest insects, causing the pest insects to become the dominant species.
If your gardenia has whitefly, drops lots of yellow leaves, and currently or in the past has been covered in black sooty mold, the plant would likely benefit from some form of intervention.
There are many options for managing whitefly, including organic and synthetic pesticides. Some gardeners have reported taking their vacuum cleaner or shop vac into the yard and simply vacuuming off the insects. While effective, this method will need to be repeated once a month through the summer, or whenever adult whiteflies are present.
Insecticides that can be used by organic gardeners to control this pest include insecticidal soap and horticultural oil. One benefit of these products is they are less harmful to beneficial insects, as well as being safer for pets and people.
To be effective, horticultural oils and soaps need to be applied thoroughly to the backs of leaves all over the plant. They will need to be reapplied once a month through the summer.
Synthetic insect control products containing pyrethroid insecticides will also control whitefly, but are very damaging to beneficial insect populations. These include insect killers that contain the active ingredients permethrin, cyfluthrin, bifenthrin and lamba cyhalothrin. These are sprayed on the leaves and must be reapplied over the summer.
Another synthetic insecticide option is imidaclopyrid, often marketed as Merit. This systemic chemical is applied to the roots, which absorb and move the chemical throughout the plant. The effects last for several months, so this product only needs to be applied once a season.
Systemic products like Merit are less damaging to beneficial insects, which do not feed on plant tissue, but recent research has shown they can harm pollinators which feed on plant nectar.
Always read and follow all label directions when using any pesticide.
Learn more: For assistance with pest identification and management, contact your local extension office. If you live in Pender County, call 259-1235. In New Hanover County, call 798-7660. In Brunswick County call 253-2610. Or, visit www.cesNCSU.edu, where you can post your questions to be answered by an expert. Visit the Pender Gardener blog to stay up to date with all the latest gardening news at PenderGardener.blogspot.com.
Gardenia Bugs – How To Control And Eliminate Gardenia Insects
Gardenias are beautiful flowers that a lot of people put in their gardens because of their beauty and ability to withstand many soil and temperature differences. They last through the season and will beautify any area around the home. However, they are susceptible to a few gardenia insects and related diseases. Let’s take a look at some common gardenia pests and their related problems with gardenias.
Common Gardenia Insects
One of the biggest gardenia leaf pests is the aphid. These can be quite challenging to deal with. These pesky gardenia bugs have soft little bodies and are tear-shaped. They cluster usually below leaves and around new growth on the gardenia plant. The aphids actually suck the fluid from the plant, which is why they like the new growth because it tends to be more lush and moist. Because they are a sucker, these garden insects can spread viruses as well.
As far as gardenia insects go, these particular gardenia bugs are quite hard to control. It is best to keep weeds down to a minimum in your flower garden and if you see ladybugs, don’t kill them. Ladybugs will eat the aphids. There are some pesticides that will work to control aphids, but you want to be sure not to kill the good bugs with the aphids. Neem oil is a good choice.
Another of the gardenia pests is the mealybug. Mealybugs are the most common gardenia leaf pests you will see. They are white and found in masses along the leaves of the gardenia. They tend to hide themselves along protected areas of the plant.
Common Insect Related Gardenia Diseases
Other than gardenia bugs, there are a few other gardenia diseases to consider. One of the worst gardenia diseases is sooty mold. Sooty mold is a foliage disease that turns the leaves of the gardenia black. It doesn’t injure the plant, but it does prevent sunlight from getting to the plant via the leaves, so the plant doesn’t perform as much photosynthesis. This is bad for the plant and can inhibit growth.
Sooty mold thrives on the honeydew created by gardenia bugs like aphids. If you control the aphids, you will also be able to control sooty mold.
Keeping these problems with gardenias in check requires constant diligence. Be sure to check your plants frequently and deal with any gardenia pests quickly to reduce the damage they cause.