Heavy rains have brought much-needed moisture, and with the rains come the insects. In my garden, potatoes have white flies. Eggplants have aphids. Roses have thrips. Time for integrated pest management procedures. Integrated pest management has one primary goal: Keep pest populations low enough to prevent significant damage. IPM includes identifying and monitoring pests, setting reasonable thresholds of control and using cultural, mechanical, biological and chemical controls. These practices focus on minimizing damage while protecting pollinators, saving money, and — over the long-term — reducing pesticide resistance.
Early detection is very important. First, correctly identify the pest. For instance, thrips are tiny, yellowish-brown insects with fringed or feathery wings. At less than 1/16-inch long, they are barely visible without a magnifying glass. I found them by noticing some distorted rose buds. Blowing lightly into the blooms, I was horrified to see hordes of tiny insects scurrying inside the buds. Thrip damage to roses usually occurs from early to midsummer. Distorted buds open only partially or prematurely. My rose petals were streaked silvery-white with brown edges. White and light-colored rose blossoms (like Peace hybrid tea roses) are particularly attractive to thrips.
I immediately went online to Clemson’s HGIC and discovered that control of thrips is difficult. Insecticides are available, but timing is very important. A spray must be applied before thrips enter unopened buds. Because rose blooms expand rapidly, it is challenging to keep the blooms adequately covered. I began scouting the rose bed early each morning. Insecticidal soaps help control thrips, but thorough coverage is necessary. I also spoke to a Rose Society representative at the recent Home and Garden Show who advised me to apply a systemic mix every four weeks. Foliar systemic insecticides penetrate closed flower buds to kill thrips inside. By following the HGIC and Rose Society advice to use three sprays at 5- to 7-day intervals and applying a systemic mix, I now have thrips under control. I still see a few, but Peace roses have been saved.
Whiteflies in the vegetable garden must be controlled before they spread across the entire garden of tomatoes, cucumbers and beans. Whiteflies are approximately 132nd of an inch long and appear white or cream-colored. They undergo four nymphal stages before they pupate and become adults. Typically, whiteflies are found in groups and are commonly on the underside of plant leaves. Whiteflies are a common pest of cucurbit crops and may spread harmful viruses. Whiteflies also weaken plants by feeding on their sap. Sticky honeydew is excreted and covers the plant with a dark-colored sooty mold. This mold reduces the ability of the plant to conduct photosynthesis and can result in reduced yields. Obviously, we need to control whiteflies now.
Clemson’s HGIC notes that whiteflies can be managed culturally by providing proper nutrition and irrigation for plants. Using reflective mulches is proven to be effective against whitefly disease transmission. First, we’ll watch the potatoes carefully (we’re currently digging them anyway) and give cultural controls a chance. Monitoring lets us know when to move forward with chemical controls as the summer progresses. In South Carolina, whitefly populations are higher in the warmer months going into the fall, which allows spring crops the opportunity to avoid severe infestation. Always, with any chemical application, read and follow the label.
Aphids are a common problem in the garden. Fortunately, other insects help to control aphids. Clemson’s HGIC always recommends that the home gardener first use cultural methods that allow beneficial insects to thrive. Beneficial insects can keep aphid populations in check. Next, mechanical controls like filling yellow pans with water to trap aphids might prove an effective control measure for aphids. Again, careful identification and conscientious monitoring are important. When the problem seems to be growing and significant damage occurs, then carefully use chemical means of control. It’s not wrong to spray as long as one does it with care.
Some pollinators are quite lovely. Because pollinators can be harmed by indiscriminate spraying, use less deadly methods to control the bad pests for as long as possible. For instance, a moth named Hyalophora cecropia, the cecropia moth, is North America’s largest native moth. Cecropia moth larvae are most commonly found on maple, cherry, and sweetgum. I’m not sure why this particular moth decided that my front porch was suitable for her eggs, but she laid her eggs all around a windowsill on my front porch. The eggs have hatched into tiny black caterpillars. Now I’m feeding the tiny caterpillars fresh sweetgum leaves every day. The first instar larvae had small black hairs all over their body. They are beginning to turn yellow green and will become large and bluish green. The caterpillars will reach maturity in autumn at 4 to 4.5 inches. Once the caterpillars reach maturity, they should spin large brown cocoons longways on trees or wooden structures. They will emerge as adults in the first two weeks of seasonally warm weather early next summer. I hope to watch the progression of this wonderful moth.
As summer progresses, the pests will arrive, but we can protect our pollinators. Use IPM practices: Identify the pests, do some research on Clemson’s HGIC, talk to the experts. Monitor the bad to protect the good and the lovely insects in the garden. When resorting to chemical controls, read the label and carefully apply as directed. Happy gardening.
Hyalophora cecropia, the cecropia moth, is North America’s largest native moth.
Hyalophora cecropia, the cecropia moth, is North America’s largest native moth.
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