This spring the Diagnostic Lab received some interesting plant samples showing very different kinds of damage from the same cause: dramatic stunting and distortion of new foliage on fuchsia, stippling and dark specks (droppings) on the upper sides of calibrachoa leaves. The fuchsia grower was not sure what the cause was and suspected broad mite (very reasonable based on symptoms) and for the calibrachoa grower it had seemed the thrips were Ďin check,í but tapping foliage over a white paper dislodged large numbers of thrips from each plant, which we identified in both cases as western flower thrips. Notorious for resistance to some insecticides, identifying the culprit helped in choosing effective controls. WFT is generally associated with flower distortion, white blotches on petals, and leaf scarring and hasnít been among the more common pests I encounter on callies, but these instances show itís good to keep an open mind. When submitting thrips for ID be sure to collect some adult thrips for the sample.
Dan GilreinEntomologist, Cornell Cooperative Extension of Suffolk County
Dan Gilrein is the Extension Entomologist with Cornell Cooperative Extension of Suffolk County at the Long Island Horticultural Research and Extension Center, Riverhead, NY since 1995 and previously served there as IPM Specialist with Cornell from 1987. In his current position he conducts applied research on control of arthropod pests in food crops and on ornamental plants, provides diagnostic services to the horticultural industries, and conducts educational programs and presentations for industry, government officials, civic groups and the public on pests and pest management.