Adult -The small adult, about 3.5 mm long and 2.4 mm wide, has lacy wings that are unusually broad. It is pale yellow, with yellowish legs and antennae.
Egg -The yellowish-white egg is 0.4 mm long and 0.2 mm wide. Basically cylindrical, it is tapered at both ends, with the neck bent to one side. The eggs are deposited in irregular rows, usually along the larger veins. Their caps are level with the leaf surface. The females deposit a brown substance over the eggs, which hardens to form a varnishlike covering.
Nymph -Unlike most lace bugs, the rhododendron lace bug has only four nymphal stages. The nymphs feed in groups in the younger stages. They range from 0.9 to 2.1 mm in length and are black and spiny (Color Plate 3AA).
Host Plants -The rhododendron lace bug attacks over 120 types of rhododendrons, as well as mountain laurel and fetter-bush.
Damage -Both the nymphs and adults prefer young leaves, which they damage by extracting the sap. The upper surfaces become mottled with white spots, and many times the leaves will dry and shrivel. The undersurfaces are also discolored with the excrement and cast skins of the insects (Color Plate 3AA).
Life History -These lace bugs overwinter as eggs, which hatch in April in the area of Washington, D.C. There are only four nymphal stages, which require about 30 days for development. The eggs are usually laid in new leaves along the midvein or a short distance from it. As many as 170 eggs can be found on a single leaf. Nonoverwintering eggs hatch in about 3 weeks. The insect seems to favor relatively well-lighted sites, but bushes in the shade can also be badly infested. The pests are commonly transported in the egg stage on nursery stock.
Rhododendron should be treated when the lace bugs are first noticed. Properly labeled chemicals should be used, and safety precautions listed on the label should be followed. For specific chemical controls, see the current state extension service recommendations.
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