Effects of 4 Horticultural Oils on Whitefly Oviposition, 1987

Twenty-five 3-wk-old 'Iceberg' chrysanthemums were randomly divided into 5 groups of 5 plants each, and all but 3 upper leaves from each plant were removed. Plants were sprayed with water, 2% (vol/vol) Sunspray 6E, 11% (vol/vol) of an experimental oil (Sun Refining Company, Philadelphia, Pa.), 2% (vol/vol) Ortho Volck Oil Spray, or 2% (vol/vol) Natur'l Oil. Foliage was allowed to dry, and then all plants were placed in random arrangement for 24 h in a greenhouse among tomato plants that were heavily infested with greenhouse whiteflies. After exposure, all leaves from each plant were frozen to kill adult whiteflies. The eggs on each leaf were counted and the area of each leaf was measured. Counts were calculated on a per 100 cm2 leaf area basis so that comparisons between plants with different leaf areas could be made.