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Spring & Summer Insects – Japanese Beetle

Remember digging around as a kid and coming upon these white grubby worms. We used to try to fish with them. Don’t remember if I ever caught anything. Then there were these shiny, metallic green insects with copper-brown wing about 3/8-inch in length. These insects are probably both different stages of the Japanese beetle, and this guy can reek havoc on your lawn and garden!

 

The beetle starts as a small white egg laid in the soil. If moisture is sufficient, they will absorb it and enlarge, becoming rounder as they do. They grow into the white grub stage that is so familiar in lawns. By August they are about full size (almost an inch long). They can live in almost any soil and a major infestation of these grubs can destroy a lawn in short order.

 

Japanese beetles overwinter in the grub stage. As the soil temperature lowers they move deeper. When the temperature starts to rise again in the spring they move back up to the roots of you plants and start feeding again. After a feeding period of 4-6 weeks, the grubs pupate in an earthen cell and remain there until emerging as adults. Adults generally emerge from the ground sometime from May to July, depending on your location. They live for about 30 – 50 days feeding on your plants. After a few weeks the females dig into the soil and lay their eggs. They can lay 40 – 60 eggs in their lifetime.

 

Adults fly long distances to food plants; so, just because you see an adult infestations, does not necessarily mean that they are in your turf. Adults feed on leaves and flowers of many plants including rose, bean, grape, and crabapple. Feeding injuries to leaves usually result in conspicuous “skeletonizing injuries” where larger veins are avoided leaving a lacy “skeleton” of the leaf.

 

Turf control. Look for areas of brown turf and search in adjacent green areas for grubs and pupae. If the damage is extensive insecticides may be needed to control grubs and adults. There are several granular insecticides for grubs. The best time to apply is from mid-July until end of September. There are also several organic treatments as well.

 

For adult beetles simply removing the beetles by hand may be the best solution if the infestation is not severe. The presence of beetles on a plant attracts more beetles. Thus, by not allowing beetles to accumulate, plants will be less attractive to other beetles. Different chemicals are available to kill the adults but should never be applied in windy conditions or when bees are foraging.

 

Japanese beetle traps. Think twice before using the trap. Most traps contain a lure with the scent of flowers and the sex pheromone of the female. The pheromone will attract beetles from a few thousand feet resulting in more beetles fling toward traps than are caught.

 

Cultural Control. Carefully selecting plants that are not susceptible to Japanese beetles is the best way to prevent them. Certain common landscape plants are inevitably attacked. Your local nursery should be able to provide you with a list of plants seldom damaged as well as offering suggestions on best chemical applications for your area to use to control a Japanese beetle infestation.

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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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