Pay close attention to your azaleas now to prevent ghastly yellowed and stippled leaves caused by the azalea lace bug. The lace bug feeds on the underside of leaves, but damage is apparent on the upper surface. Lace bugs leave cast skins and black, gummy, varnish-like feces on the underside of leaves. They deposit eggs, cemented with a brown crusty material, near leaf veins. Warm temperatures cause the eggs to hatch, usually in May. The damage becomes more visible as successive generations hatch in June and July. The lace bug thrives on azaleas grown in the sun; it falls victim to spiders on azaleas properly grown in the shade. Insecticidal soap, horticultural oil, or a systemic insecticide help to control this pest.
Determine the damage threshold for your plants. Decide ahead of time how much injury you can tolerate and don’t take action until this level is reached. Premature measures, taken when they are not necessary, may lead to a resurgence of another pest or harm beneficial insects, mites, and spiders.
Have you heard of an insect with a 13 or 17 year life span? We usually think insects are short-lived, but the periodical cicada can live longer than your cat or dog! Unlike many pests, the adult cicadas don’t feed on leaves, but cause damage by depositing their eggs in the bark of trees. The females saw into the bark of small branches, splintering the sapwood to make slits for their eggs. Damaged branches break off easily in a storm or high winds. Once the eggs hatch, the nymphs drop to the ground, burrow into the soil, and remain there for the remainder of their development. Nymphs suck sap from the roots of trees, but not enough to inflict serious harm. Keep your eyes open for dead twigs and branches. Trees showing conspicuous damage from egg laying include oak, hickory, ash, and dogwood. Mature, established trees usually recover from the damage. Small and newly planted trees may be seriously injured or killed. Protect them by covering them with netting.
Your garden will benefit from your knowledge of what insects populate it. Monitor your garden frequently to find small pest populations before they become destructive. Look for beneficial insects that are feeding on the pests, too. Their relative abundance is a key component in making accurate decisions on whether or not pesticides are necessary. For example, if you observe many beneficial insects and small numbers of pests, you may need to do nothing. Problems usually will not become severe if you notice them early and keep an eye on them. To find small numbers of small insects and mites, place a sheet of white paper under a branch or plant and tap the foliage so these tiny creatures fall onto the paper.
Watch for powdery mildew on your dogwoods. It is a serious disease that stunts new growth and stops growth entirely if severe. Unlike most fungi, powdery mildew does not require water on the leaf surface for spore germination, so it will invade even in dry weather. Neem-based pesticides or horticultural oil will cure the problem.
It’s not too late to plant some vegetables! Plant summer squash in late June to avoid the squash borer. You will miss the prime time for borer damage. The borer feeds in the stems in early summer and completes its life cycle soon after. A late planting of tomatoes and peppers will provide a bumper crop this fall and will avoid diseases that are damaging in hot, humid weather. These plants won’t set fruit during high summer temperatures, but the large plants will produce loads of fruit when nights get cooler in late summer and early fall.
Reduce water usage on your lawn in hot, humid weather. Your grass will go dormant if allowed to dry out and will escape diseases that are common during summer months. Remember to mow high to choke out weeds and let clippings fly to recycle nutrients and reduce the need for fertilizer.