Greenhouse Whitefly Control on Poinsetta, Pennsylvania, 1978

Cuttings of the Annette Hegg Diva strain of poinsetta were taken on June 29, rooted, and transplanted to 4 inch pots containing an equal mix of peat, perlite, vermiculite and mush-room casing soil. Plants were grown under natural light and no growth regulators or insecticides were applied. Water and fertilizer were furnished through a trickle flow system. The greenhouse temperature average 21°C. Eight treatments plus a control were applied in a randomized complete block design. Treatments were replicated 10 times. Foliar sprays were applied to runoff with a compression sprayer and granular insecticides were measured and sprinkled over the surface of the soil. Samples were taken before spray and at days 3,7,14, 21 and 28. Counts were made by counting the number of live nymphs on a 5cm2 area of leaf surface. Percent control is expressed as the average number of nymphs found per treatment compared to the control.