Trapping Patterns of Entomophthora gammae (Weiser) (Entomophthorales: Entomophthoraceae) Conidia in a Soybean Field Infested with the Soybean Looper, Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae)

Abstract

Air-borne conidia of the fungus Entomophthora gammae (Weiser), a pathogen of Pseudoplusia includens (Walker), were sampled continuously during August and September over a soybean field using a Burkhard spore trap. Conidia were first detected 1 week before host larvae were detected. Initial collections coincided with a cool, wet period. Once larvae were found, conidia were detected daily. Peak collections occurred at intervals of ca. 9 to 12 days, and highest numbers coincided with maximum host population levels. Daily collection patterns showed that initial detection usually occurred between 2000 and 2100 hours, with maximum production between 0000 and 0600 hours and essentially no production between 1200 and 1800 hours. Detection was confined to periods of near 100%RH, which normally were present for 8 h or more nightly during the trapping period.