Control of the Serpentine Leafminer on Chrysanthemum Under Greenhouse Conditions, Winter 1993

Abstract

Abstract Chrysanthemums were obtained as rooted cuttings and potted in 15 cm pots in a greenhouse at UCR and allowed 8 wk growth (25-30 cm tall) before use. During wk 8, the plants were exposed to heavy populations of leafminers. By wk 10, all plants were moderately infested with leafminers. To ensure an equal distribution of leafminers/treatment, plants infested with approximately equivalent numbers were assigned to each treatment (4 plants/treatment). Azadirachtin treatments were applied at 40 psi to runoff using a hand sprayer. The NTN 33893 2.5%G and 240F were applied as soil treatments and drenched into the soil with approximately 250 ml of water. Pre-treatment counts and treatment applications were made on the same day (day 0). Posttreatment counts (the number of adults emerging from pupae) were taken 24 DAT. Number of emerging adults were expressed as a mean percent change from the pre-treatment count and analyzed using ANOVA. As individual leafminers were not held on isolated leaves for a specific period of time, more eggs successfully hatched than were counted in the pretreatment count; thus certain treatments showed positive percentage population increases.