FOLIAR APPLICATION OF STEINERNEMA-CARPOCAPSAE (RHABDITIDA, STEINERNEMATIDAE) TO CONTROL LIRIOMYZA-TRIFOLII (DIPTERA, AGROMYZIDAE) LARVAE INCHRYSANTHEMUMS

Foliar sprays of Steinernema carpocapsae (Weiser) All strain (10,000 i nfective juveniles per milliliter) on chrysanthemums ('Manatee Iceberg ') effectively controlled second instars of a serpentine leafminer, Li riomyza trifolii (Burgess) (>85% mortality), in laboratory tests, unde r conditions of high humidity in plastic cages. Increasing the duratio n of caging chrysanthemums gave consistently higher mortality of leafm iner. Free moisture on the leaf surface and increased humidity enhance d the survival and activity of entomopathogenic nematodes. Glycerine w as the most effective adjuvant tested for increasing the mortality of leafminer by nematodes. Wilt Pruf, Folicote, and Sunspray Ultrafine Sp ray oil were ineffective adjuvants. A research greenhouse test using t wo consecutive applications of S. carpocapsae (3 and 4 d after oviposi tion by leafminer) gave >80% mortality of leafminer with or without gl ycerine. Abamectin gave significantly greater mortality (99.6%) than a ny nematode treatment.