An Update on Pyrethroid Resistance in Tobacco Budworm and Bollworm in Louisiana

Jerry B. Graves, B. Roger Leonard, and Anthony M. Pavloff


 
ABSTRACT

Over 5700 male tobacco budworm moths were bioassayed from May through September 1988 against 1, 5, 10 and 30 µg/vial doses of cypermethrin. Examination of these data reveal that pyrethroid resistance in tobacco budworm varied with location and date of bioassay. Resistance levels decreased during May and June when pyrethroid use was low and increased dramatically during late July and August when pyrethroids were being used extensively. Overall pyrethroid resistance levels in May, June and early July were lower in 1988 than in 1987. However, due to the fact that the 1988 cotton crop matured later than the 1987 crop (which resulted in greater use of pyrethroids in August and September), pyrethroid resistance levels during August and September 1988 were higher than the levels recorded during those same months of 1987. Resistance levels were generally highest in areas of extensive cotton production (hence more extensive use of pyrethroids) and lowest in areas with little or no commercial cotton production. The responses of over 800 tobacco budworm moths to tralomethrin at doses of 1, 2.5, 5, 10 and 30 µg/vial indicated a similar pattern of resistance as that observed with cypermethrin. These data support previous results that indicate that resistance to a pyrethroid generally confers cross-resistance to other pyrethroids. The responses of over 1400 bollworm moths to cypermethrin at doses of 0.5, 1, 2 and 5 µg/vial serve as baseline data for this pest. The data obtained reveal that bollworms are much more susceptible to cypermethrin than tobacco budworms. However there was some variation in the tolerance level of bollworm moths based on location of collection. The most pyrethroid tolerant bollworm moths were collected from the same locations as the most resistant tobacco budworm moths. Overall all of the data collected suggest that the Tri-State (Mid-South) Pyrethroid Resistance Management Plan has been successful in delaying pyrethroid resistance development in Heliothis. However low tobacco budworm populations during 1987 and 1988 have no doubt been responsible for the virtual absence of field control failures.



Reprinted from Proceedings: 1989 Beltwide Cotton Research Conferences pp. 343 - 346
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998