Control of the Greenpeach Aphid on Chrysanthemum Under Greenhouse Conditions, Spring 1989

Chrysanthemums were obtained as rooted cuttings and potted in 15 cm pots in a greenhouse at UCR and allowed 4 wk growth before use. During the growth phase, the plants were exposed to heavy populations of aphids within the greenhouse. By 4 wk, the plants had obtained a moderate amount of aphids for treatment. Only the terminal portions of the plants were used for aphid counts (3 unexpanded leaves) and marked with a twist tie around the stem at that point. Therefore, posttreatment counts would be made of the same aphids and their young if produced. Plants were assigned to treatments to ensure an equal distribution of aphids/treatment. Six plants/treatment were sprayed at 45 psi using a hand sprayer. Treated plants were held on raised benches in a greenhouse at 26.7°C and ambient relative humidity. Posttreatment counts were taken at 5 and 8 d.