Status of insecticide resistance in tobacco budworm and bollworm in Louisiana during 1998

Document Type

Conference Proceeding

Publication Date

12-1-1999

Abstract

In 1998, resistance was again documented in tobacco budworm populations to pyrethroid insecticides. Over 769 tobacco budworm moths were bioassayed for pyrethroid resistance from May through August 1997 using a discriminating dose of 10 μg in the adult vial test. Pyrethroid resistance levels in 1998 were slightly lower than in 1997. Percent survival in May, June, July and August was 41, 48, 51, and 60%, respectively. The high survival level in May and June indicates that a large percentage of the tobacco budworm population was resistant to pyrethroids before growers began to use pyrethroids for tobacco budworm control. The data suggests that pyrethroids may no longer provide effective control of tobacco budworm populations. Over 1950 male bollworm moths were assayed against a 5μg/vial dose of cypermethrin. Bollworm moth survival levels increased dramatically in 1998. July survival levels were 27%, the highest observed since inception of monitoring in 1998. This data indicates that bollworm susceptibility to pyrethroid insecticides is changing.

Publication Source (Journal or Book title)

Proceedings of the 1999 Beltwide Cotton Conference, January 1999, Orlando, Florida, USA

First Page

872

Last Page

878

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