ASSOCIATION OF THE SWEET-POTATO WHITEFLY WITH A SILVERLEAF DISORDER OF SQUASH

The sweetpotato whitefly, Bemisia tabaci (Gennadius), was associated with symptoms of a silverleaf disorder of acorn squash (Cucurbita pepo L. cvs. Table King Bush and Table Ace) in cage studies in the greenhouse. Symptoms appeared on uninfested leaves that developed after plants were infested with the whitefly. When the infested lower leaves were removed and the young leaves protected from infestation with insecticides, new growth was asymptomatic or nearly so and symptomatic leaves remained symptomatic. Symptom expression was related more to nymphal density than to adult density since the relationship between log nymph density and symptoms was linear when adult densities were equal.