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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #174726
Title: LABORATORY BIOASSAYS OF ENTOMOPATHOGENIC FUNGI FOR CONTROL OF DELIA RADICUM (L.) LARVAE

Author
item Bruck, Denny
item SNELLING, JANE - OREGON STATE UNIVERSITY
item DREVES - OREGON STATE UNIVERSITY
item Jaronski, Stefan

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2005
Publication Date: 6/1/2005
Citation: Bruck, D.J., Snelling, J., Dreves, Jaronski, S. 2005. Laboratory bioassays of entomopathogenic fungi for control of Delia Radicum (L.) larvae. Journal of Invertebrate Pathology. 89:179-183.

Interpretive Summary: The cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae) is a serious pest of Brassicaceae crops (i.e. broccoli, cabbage, turnip, rutabaga) in North America and Europe. Females lay eggs around the base of wild and domesticated cruciferous plants. Larvae feed directly on the roots resulting in severe reductions in crop quality and yield. In root crops such as rutabaga and turnip, larvae can render the crop unmarketable if more than slight feeding damage is evident at harvest. Current D. radicum (L.) management relies almost entirely on chlorpyrifos (Lorsban TM). Due to resistance developing in some D. radicum populations, alternative control strategies are needed. Laboratory soil bioassays of insect killing fungi were performed at economic field rates for in-furrow (3.85E+06 spores/g dry soil) and broadcast (3.85E+05 spores/g dry soil) applications with 3 isolates of Metarhizium anisopliae (F52, ATCC62176, ARSEF5520) and one isolate of Beauveria bassiana (GHA). All isolates tested killed D. radicum larvae. The conditionally registered (with the US Environmental Protection Agency) M. anisopliae isolate (F52) performed best, killing an average of 85 and 72% of D. radicum larvae at the high and low concentration, respectively. The mean concentration of F52 spores required to kill 50 and 95% of 2nd instar D. radicum was 2.7E+06 and 1.8E+08 spores/g dry soil, respectively.

Technical Abstract: The cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae) is a serious pest of Brassicaceae crops (i.e. broccoli, cabbage, turnip, rutabaga) in North America and Europe. Current Delia radicum (L.) management relies almost entirely on chlorpyrifos (Lorsban TM). Due to resistance developing in some D. radicum populations, alternative control strategies are needed. Laboratory soil bioassays were performed at economic field rates for in-furrow (3.85E+06 spores/g dry soil) and broadcast (3.85E+05 spores/g dry soil) applications with 3 isolates of Metarhizium anisopliae (F52, ATCC62176, ARSEF5520) and one isolate of Beauveria bassiana (GHA). All isolates tested were infective to D. radicum. The conditionally registered M. anisopliae isolate (F52) performed best, killing an average of 85 and 72% of D. radicum larvae at the high and low concentration, respectively. The mean LC50 and LC95 of F52 against 2nd instar D. radicum was 2.7E+06 and 1.8E+08 spores/g dry soil, respectively.