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

Foliar sprays of Steinernema carpocapsae (Weiser) All strain (10,000 infective juveniles per milliliter) on chrysanthemums ('Manatee Iceberg') effectively controlled second instars of a serpentine leafminer, Liriomyza trifolii (Burgess) (>85% mortality), in laboratory tests, under conditions of high humidity in plastic cages. Increasing the duration of caging chrysanthemums gave consistently higher mortality of leafminer. Free moisture on the leaf surface and increased humidity enhanced the survival and activity of entomopathogenic nematodes. Glycerine was the most effective adjuvant tested for increasing the mortality of leafminer by nematodes. Wilt Pruf, Folicote, and Sunspray Ultrafine Spray oil were ineffective adjuvants. A research greenhouse test using two consecutive applications of S. carpocapsae (3 and 4 d after oviposition by leafminer) gave >80% mortality of leafminer with or without glycerine. Abamectin gave significantly greater mortality (99.6%) than any nematode treatment.