Lace bugs are doing serious injury to azaleas and Pieris japonica (andromeda) in some gardens in the Washington area. It is a good idea to inspect your plants and if they are infested, specialists recommend spraying them with Sevin. Directions on the label for mix and application should be followed closely.
These insects feed by sucking sap from the underside of the foliage. Injured leaves become stippled and mottled with grayish blotches. Adults are about one-eighth inch long, nymphs (young) much smaller. They are all lace-like in appearance.
Hinodegiri and Kaempferi varieties of azaleas are more likely to be attacked than others. Evergreen azaleas growing in shade are seldom bothered by lace bugs while those in full sun are very susceptible.
It is important to spray the undersides of the leaves because that is where the insects feed. Do not spray unless your plants are known to be infested. Spray in late afternoon because Sevin applied between 10 a.m. and 2 p.m. may kill bees which are active.
It may be necessary to spray a second time four to six weeks later to get a new generation which may have hatched from eggs.
The insects overwinter in the egg stage on the leaves of infested plants. Usually the over-wintering eggs are at the bottom of the foliage. The eggs of the summer generation are on new foliage at or near the top of the plant.
The damage that has been done by the lace bugs will not be corrected by spraying. Leaves that have been injured will never regain good color and sooner or later will drop off. If the plant is fairly vigorous new leaves will appear.
To prevent a buildup of lace bugs on vulnerable plants, it is recommended that they be checked about once a month. Use a magnifying glass and inspect the undersides of several leaves.
Because of the serious damage many azaleas suffered due to the weather last winter, it is all the more important to take the best care of them this summer, to give them a chance to fully recover.
During prolonged dry weather, they should be watered thoroughly every week or 10 days. Those growing in full sun will need watering much more than those in the shade.
The ground was frozen deeper and stayed frozen for long periods and the roots of the plants were unable to get moisture from the soil. Evaporation of moisture from leaves and twigs went on almost continually (brisk winds accelerate the process) and dehydration occurred.
Many Buford hollies that were exposed to northerly winds were killed to the ground. But if they were more than 7 or 8 years old, they may send up new shoots from the roots. Rhododendrons, evergreen magnolias and camellias are showing some regrowth after having lost all their leaves.
Like the hollies, many boxwood plants suffered terminal dieback due to desiccation. Ground-cover junipers also suffered heavy damage and they are slow in showing recovery. The upright varieties were not particularly hurt. A few crape myrtle bushes in well-protected locations appear to have survived in good shape.