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ARS Home » Research » Publications at this Location » Publication #89521
Title: EFFICACY OF ULTRA-LOW VOLUME AND HIGH VOLUME APPLICATIONS OF FIPRONIL AGAINST THE BOLL WEEVIL

Author
item Mulrooney, Joseph - Joe
item WOLFENBARGER, DAN
item HOWARD, KEVIN - DELTA & PINE LAND CO.
item GOLI, DEEPA - SOUTHERN TESTING RES. LAB

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The effectiveness of fipronil applied in both low and high volume sprays against boll weevils has not been adequately documented. Both ground and aerial application tests were conducted in Texas and Mississippi during 1993 - 95 to determine the efficacy of fipronil in the field. In addition a topical bioassay was conducted to determine differences in susceptibility of laboratory and field collected strains of boll weevils to fipronil. Topical bioassays of fipronil using field collected strains of boll weevil from both the Lower Rio Grande Valley and from Louisiana showed equal toxicity. In Texas in 1993 and 1994, rates of fipronil at 0.025, 0.05 and 0.08 lb/A reduced the percentage of damaged squares and bolls below the untreated check. Ultra low volume (ULV) ground application tests in Mississippi in 1995 showed no differences in toxicity of two rates (16 and 12 oz/A) of ULV malathion and fipronil at 0.05 lb/A until 3 days after application at which time mortality was 95 and 60% for the 16 oz/A rate of ULV malathion and fipronil at 0.05 lb/A, respectively. Fipronil rates of 0.05 and 0.038 lb/A applied at ULV by aircraft were equally effective against boll weevils. In a subsequent test, 0.025 and 0.038 lb/A rates of fipronil were equal in toxicity to boll weevils. Fipronil is highly effective against boll weevil in either low volume sprays in oil or high volume sprays in water. Once it is registered in cotton it should be an good alternative insecticide for use in the Boll Weevil Eradication Program.

Technical Abstract: Topical bioassays of fipronil against a field collected and a laboratory reference strain of boll weevil from the Lower Rio Grande Valley showed equal LD50 values. LD50's of field collected strains from Louisiana and Lower Rio Grande Valley were equal. In Texas in 1993, 15 applications of fipronil applied at 0.028, 0.056, and 0.084 kg(AI)/ha were equally effective at reducing percentage damage squares and bolls below the untreated check. In 1994, 14 applications of 0.056 kg(AI)/ha effectively reduced damaged fruit below that of the untreated check. Yields of treated cotton in both years were not significantly different from the check. Ultra low volume (ULV) ground application tests in Mississippi in 1995 (Test 1) showed no differences in toxicity of two rates (1.02 and 1.36 kg[AI]/ha) of malathion and fipronil at 0.056 kg(AI)/ha. Fipronil applied ULV by aircraft at rates of 0.043 and 0.056 kg(AI)/ha (Test 2) were equally effective against boll weevils in bioassays of treated leaves. In a subsequent test, 0.028 and 0.043 kg(AI)/ha rates of fipronil (Test 3)were equal in toxicity to boll weevils. Fipronil is highly effective against boll weevil in either low volume sprays in oil or high volume sprays in water.