EFFECTS OF INSECTICIDES ON EMERGENCE OF GLASSY-WINGED SHARPSHOOTER NYMPHS IN NURSERY CITRUS, 2003

Abstract

Six insecticides and an untreated control were tested to determine the their effects on emergence of GWSS nymphs from egg masses. Adult GWSS were collected from an untreated citrus orchard in Bakersfield California and caged on 2-year-old, potted, 'Eureka' lemon trees in a greenhouse at Willits and Newcomb Nursery in Arvin, California during Jul 2003. Five cages were attached to each tree and five adult female GWSS were placed in each cage. The adult GWSS were allowed to deposit eggs for 7 days and then the adults were removed from the cages. Leaves were inspected, egg masses were circled, and the egg masses were divided among treatments. Insecticides were mixed as field rates in 750 gpa (Provado, Sevin, Assail, Esteem and F-1785) or 100 gpa for Mesurol. Leaves infested with egg masses were hand sprayed with various rates of formulated insecticides or sprayed with water, and branches were caged with polyester mesh cloth bags. One week after treatment, cages were opened, emerged nymphs counted, and egg masses were examined under a stereo-microscope to determine the percentage of non-emerged nymphs. The experiment was replicated on two dates for Sevin, Prasad, Assail, and Mesurol, but only once for Esteem and F17B5 because of the lack of efficacy of these insecticides. Mean percent of non-emerged GWSS nymphs per tree was analyzed using ANOVA and LSD (P £ 0.05) after arcsine transformation of the data.