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Efficacy of Azinphosmethyl and other Insecticides against the Boll Weevil in the Field

Dan A. Wolfenbarger


ABSTRACT

Azinphosmethyl was evaluated for control of boll weevils in cotton following season long sprays in 1982, 1983, 1990, 1991, 1992 and 1993 in the Lower Rio Grande Valley (LRGV). Methyl parathion and oxamyl were evaluated for control of the same insect in 1990 as were bifenthrin, deltamethrin and endosulfan in 1992. Eight to 15 applications of aqueous sprays were made each year and mean percentage damaged squares and bolls were used to determine control. Azinphosmethyl treated cotton had significantly fewer percentage damaged squares than the check in 1983 and 1990. Azinphosmethyl had significantly fewer percentage damaged bolls than the check in 1982 and 1990. Seed cotton yields were significantly greater in azinphosmethyl treated cotton in 1982, 1983, 1990 and 1991 than the check. Yields in azinphosmethyl and check cotton were equal in 1992 and 1993. In 1990 methyl parathion and oxamyl at 0.56 and 0.14 kg (AI)/ha, respectively, showed significantly fewer damaged squares than the check. Yields from cotton treated with methyl parathion and oxamyl, at 0.56 and 0.28 kg (AI)/ha, respectively, were significantly greater than the check. In 1992 there was no significant difference in damaged squares and bolls by the boll weevil and yields of cotton treated with deltamethrin and the check.





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Document last modified May 20, 2002