As soggy as it has been one would hope that most of the insects had drowned, but alas, no such luck. Some have said they have become more relaxed and excited in the somewhat cooler environment and many have moved indoors to escape the constant drenches and standing puddles.
1. Lace bugs -- Normally this time of year we see a few lace bugs, but not this year as populations on azaleas, sycamores, pyracantha and a few other trees have exploded. The damage to foliage at a distance looks like a heavy mite infestation. The leaves take on a stippled look that in time blankets the leaf, giving it a bronzy grayish cast. This damage is caused by the feeding of the nymphs and adults. In some cases we are seeing the damage but no insects, but they leave their telltale signs of dark, blotchy fecal deposits on the underside of the leaves. There are two groups of lace bugs. The first are the ones we see every year that attack the azaleas, rhododendrons and lantanas, and the second are the ones that attack the deciduous trees like willow, basswood, sycamore, walnut, oak and elm. The first group overwinters as eggs embedded in the veins on the leaves, and the deciduous group overwinters as adults on and around the host. Both groups cause similar injury to the host, and the nymphs have the same appearance: a dark ovoid body with a series of spines on the dorsal surface. Adults vary in body shape; azalea lace bugs and many others are flat and broad with the expanded lacey wings, and the lantana lace bug is slim and narrow with an intricate raised-lacework pattern. The females lay eggs over a two-to-three-month period. The eggs hatch in two weeks. The immature develops through 5 instars and requires 21 days (evergreen group) to 26 days (deciduous group) to develop. There are color variations in the adult stage. Management can be obtained with Merit, Marathon, Orthene, Onyx, Discus, Talstar, Safari and Tame applications. Coverage, pH and timing are critical to reducing populations. Early detection and management of a population will reduce subsequent generations and injury. Always check to be sure populations are present before application. Figure 1.
2. Aphids -- Populations of aphids on crape myrtles, hackberries, daylilies, pecans and several other plants have exploded. Their honeydew excretions have created a blanket of sooty mold on infested plants. Remember to treat the cause of the sooty mold -- the aphid -- and the sooty mold will dry up and peel off. Aphids can be managed with several insecticides -- Orthene, Merit, Marathon, Cygon, Malathion, Safari, and Thiodan. All of these can be sprayed, but Orthene instead of spraying can be used as a slurry. Mix 4 parts of Orthene with 1 part water to make slurry. Clean off a six-to-eight-inch section of the lower trunk of the tree and apply the slurry all the way around the trunk with a small paint brush. By applying the material this way we protect the beneficials and reduce the potential for drift into unwanted areas. Figure 2.
3. Two-lined Spittle bug -- With all the rain this pest is no surprise, as they like humid, moist areas. The adults resemble large black leafhoppers with two red or orange lines across the wings and dark red eyes. They feed on a variety of grasses and ornamentals. Hosts include coastal Bermuda, centipede, St. Augustine, rye, crab, Johnson and orchard grasses and holly, redbud, aster, honeysuckle and morning glory and many small grain crops. They are rarely a problem in managed turf. Both adults and nymphs have piercing, sucking mouthparts to extract plant juices. Feeding in large numbers may kill, wither or prevent growth of turf grasses and create white blotches in the foliage of the ornamentals. The spittle bug overwinters as an egg behind leaf sheaths or in debris. They emerge in the spring, with the nymphs seeking humid environments to begin feeding. The nymphs are a yellowish tan, and soon after the initiation of feeding they begin to exude a white, frothy spittle mass which protects them from natural enemies, desiccation and pesticides if spreader stickers are not used. They feed and develop through 4 instars. They are most active in early morning, hiding during the heat of the day. The adults live about 23 days, and the female lays eggs during the last 2 week of her life. Hatching occurs about 2 weeks later. There are two generations per year. Management can be obtained with Onyx, Talstar or other pyrethroids. Treatment should only be made when population density is high. Figure 3.
4. Thrips – Thrips continue to be a problem through the season. Their feeding resembles injury from lace bugs and mites and can be confusing. Again, proper identification is essential for management. Signs of thrip infestations are the cast skins and the lemon drop-like fecal deposits on the leaf surfaces. Heavy populations can cause leaf drop and stunting of the plants. Infestations will move between ornamentals and vegetable crops with some species; others are more specific. Management can be obtained with Orthene, Malathion, Onyx, Spinosad, Tame and Talstar. Figure 4.
5. Whiteflies -- Heavy populations are reported from several areas of the state on ornamentals, vegetables and citrus. We have several species in the state that attack a wide variety of hosts. Early detection is best to assist in management of this pest, as multiple generations can overwhelm plants, and some can transmit pathogens. Use Orthene, Merit, Marathon, Safari, Cygon Malathion or Talstar. It is best to add ultra fine oil to the spray to improve contact and to penetrate the waxy excretions and coverings on the nymphs. Figure 5.
6. Citrus leaf miners – With the recent flush of growth on citrus, the citrus leaf miner has exploded. Leaves are mined, curled and disfigured on the trees. Pruning these heavily damaged shoots and treating with Spinosad will aid in managing the populations. These little moths can severely damage trees and reduce development and production if unchecked. Checking the infested leaves one can see the larvae in the mines on the leaf or the pupa in the curled edge of the leaf. Each flush of growth should be treated to help manage the moth. Some areas do have a small parasite that will help check the moth, but cold winters usually greatly reduce populations. Figure 6.
7. Devil horses, lubber grasshoppers – These large black grasshoppers with the red or orange lines on the body and the pink hind wings are the scourge in several areas presently. When disturbed they flare their wings and hiss, and many are concerned they will cause injury. The only damage or injury is to plant materials. Several calls have reported populations too dense to count. Some people report they can hear them eating on the plants. There is one generation per year. The eggs hatch from the soil in the spring and development continues through August. They tend to be gregarious, and large number may be observed on plants. They can heavily damage plants by stripping the foliage. They are large, awkward and clumsy and do not fly. Management can be accomplished using pyrethroids or Sevin with a spreader sticker or ultra fine oils. A bait, Semaspore, is also very functional. Figure 7.
Until next month,
Dale
| | Aphid infestations and sooty mold. |
| | Two-lined spittlebug, adult and nymph. |
| | Thrips and damaged foliage. |
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| | Citrus leaf miner and injury. |
| | Devil horse or lubber grasshoppers. |
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