Spring Insects – Lace Bugs

Lace Bugs!  Those speckled leaves on your rhodies and azaleas are usually a sure sign of lace bugs. Lace bug damage is first noticed as yellow spots on the upper leaf surfaces of affected plants. That’ because lace bugs damage plants by inserting their piercing-sucking mouthparts into the underside of leaves and sucking plant fluids. They kill surrounding cells as they feed causing the yellow spots to appear on the upper sides of the leaves. Heavy infestations cause leaves to brown and drop prematurely, which reduces growth or kills the plant.

Look at the undersides of leaves to detect active adults during the summer months. Turn a few leaves over and look for lace bugs with a 10 to 15 power hand lens or shake an infested branch over a white sheet of paper. The insects will fall off and may be more easily seen than on the foliage. The adults are 1/8-inch long with clear, lace-patterned wings. The transparent wings are held flat on the back. Their wings are lacy with two grayish-brown cross-bands connected in the middle. The adults have highly ornamented wings and a hood-like structure covering the head. The entire surface of the insect is covered with veins that look like lace.

Lace bugs are common pests of azalea, rhododendron, sycamore, broad-leaved evergreens and many deciduous trees and shrubs. Plants that attract lace bugs should be monitored early in order to determine if an infestation is building.

Elimination of the first generation of lace bugs is necessary if visual damage is to be avoided. Existing spotting and yellowing of leaves will not disappear once the lace bugs have been controlled. The undersides of leaves will also have brown splotches.  Most lace bug infestations occur in bright, sunny areas. If you plant lace bug-susceptible plants such as azalea and rhododendron in shady areas of the landscape, lace bugs are rarely a problem. One effective control method is simply spraying down infected plants with a hard jet of water from a hose in the spring. This will dislodge the young nymphs as they hatch in the spring. The tiny nymphs often die before they can find their way back to suitable leaves.

Insecticidal soaps and oils are usually adequate if they contact the nymphs directly. Additional applications may be needed to control nymphs hatching out of late-laid eggs or if re-infestations occur from surrounding landscapes. Make applications as soon as the eggs hatch in the spring, usually mid to late-May. Monitor the plants and repeat applications if re-infestations occur. If plants are repeatedly attacked, consider moving them into the shade.

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Spring Insects – Whiteflies

At one time or another we have all seen these tiny snowflakes fluttering about a plant. A major infestation of whiteflies can look like a flying fog! They can seem to come out of nowhere and all of a sudden! They are small winged insects which look more like moths than flies and they multiply like crazy!

Whiteflies are not true flies. They are relatives of mealybugs, scales and aphids. Like these sucking insects, whiteflies attack the leaves, buds and stems sucking the juice out of them. Although considered more of a nuisance than anything else, large numbers of whiteflies can really stress plants. The leaves of infected plants may turn yellow,twisted or stunted, and wither and drop prematurely. This insect has a host range of more than 250 ornamental and vegetable plants.

As do their relatives, whiteflies secrete “honeydew” which lures other nuisance insects onto the host plant. Ants, wasps and beetles feed off the honeydew. And when the honeydew goes bad it grows Black Sooty mold. This mold damages the plants preventing them from processing food properly!

Whiteflies cannot overwinter in freezing temperatures outdoors in the north, but can thrive year round in the south and in greenhouses, hence the name of the most prevalent Greenhouse Whitefly! Many plants become infested in greenhouses and transfer the whitefly to other plants in the garden.

Prevention is the best management. Infestations typically originate from infested plant materials. Carefully check all new plants and quarantine them before moving them into a room with susceptible plants.

Insecticidal soaps work well with adult whiteflies. They are safe so you can spray any plant – including fruits and vegetables – without any hazard to people or pets that may be eating the harvest. Soap is certified for organic gardening so it’s an excellent choice for organic growers. These are contact killers for both insect and mite pests. They penetrate the body of the pest and result in rapid death. Keep in mind that white flies in all stages spend virtually all their time on the undersides of leaves. Make sure to cover the hard to reach spots when spraying.

Whiteflies have about a 30 day lifespan. They follow the life cycle of most insects – eggs to crawler to nymph to pupae to adult and they reproduce quickly. About four days from emerging from the pupae adults laying eggs. Insecticides are not effective against immature stages of whiteflies, applications need to be made every four days to kill adults before they begin to lay eggs for the next generation. Up to 7 applications may be needed to bring well-established infestations under control.

There are other insecticides available for whitefly control. Make sure to read the product label for use on crops and directions for preparing spray solutions.

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