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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGY AND ECOLOGY OF COTTON PESTS EMPHASIZING MANAGEMENT OF BOLL WEEVILS Title: Comparative efficacy of selected insecticide alternatives for boll weevil (Coleoptera: Curculionidae) control using laboratory bioassays

Authors
item Castro, Boris - DOW AGROSCIENCES
item Armstrong, John

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 2009
Publication Date: September 1, 2009
Citation: Castro, B.A., Armstrong, J.S. 2009. Comparative efficacy of selected insecticide alternatives for boll weevil (Coleoptera: Curculionidae) control using laboratory bioassays. Journal of Cotton Science. 13:189-195.

Interpretive Summary: Efforts to eradicate the boll weevil, a major cotton pest responsible for an estimated $300 million in annual crop losses, are still ongoing in Texas and Mexico. Boll weevil eradication programs rely on malathion ULV to achieve and maintain eradication. Should this effective and economical insecticide not be available for any number of reasons, eradication efforts could be jeopardized. The objective of this project was to evaluate effectiveness of selected insecticides as alternatives to malathion ULV on native, field collected adult boll weevils using bioassays that involved exposing boll weevils to treated cotton leaves. The insecticides evaluated in the assays included malathion ULV, endosulfan, bifenthrin, encapsulated methyl parathion, oxamyl, carbaryl and cyfluthrin. Boll weevil mortality in the malathion ULV, endosulfan, encapsulated methyl parathion and bifenthrin treatments was at or near 100% by 48 h of exposure. Mortality with cyfluthrin and carbaryl was low and inconsistent. Mortality in the oxamyl treatment was intermediate between the two above groups. Highest mortality after 24 h was observed with malathion ULV (97.9%), endosulfan (86.6%) and bifenthrin (80.2%). After 48 h, mortality reached 100% with malathion ULV but was not significantly different from those of encapsulated methyl parathion (96.1%), bifenthrin (95%) and endosulfan (94.9%). Results indicate that malathion ULV is a highly effective material for boll weevil control and that encapsulated methyl parathion, bifenthrin and endosulfan also are effective in causing high mortality.

Technical Abstract: The boll weevil, Anthonomus grandis grandis (Boheman), is a major cotton pest responsible for an estimated $300 million in annual crop losses. Boll weevil eradication programs depend on malathion ULV to achieve and maintain eradication status. Should this effective and economical insecticide become unavailable, eradication efforts could be jeopardized. The objective of this project was to evaluate efficacies of selected insecticides as alternatives to malathion ULV on native, field collected adult boll weevils using laboratory bioassays. Adult boll weevils were collected with pheromone traps or reared from infested squares in the Lower Rio Grande Valley of Texas in 2007. Insecticides included malathion ULV, endosulfan, bifenthrin, encapsulated methyl parathion, oxamyl, carbaryl and cyfluthrin. Plants were sprayed with a hand-held CO2-charged sprayer except malathion ULV which was applied using an ULV applicator. Treated leaves were cut into disks, placed inside culture plates and infested with individual adult boll weevils. Boll weevil mortality in the malathion ULV, endosulfan, encapsulated methyl parathion and bifenthrin treatments was at or near 100%. Mortality with cyfluthrin and carbaryl was low and inconsistent. Mortality in the oxamyl treatment was intermediate between the two above groups. Highest mortality after 24 h was observed with malathion ULV (97.9%), endosulfan (86.6%) and bifenthrin (80.2%). After 48 h, mortality reached 100% with malathion ULV but was not significantly different from those of encapsulated methyl parathion (96.1%), bifenthrin (95%) and endosulfan (94.9%). Results indicate that malathion ULV is a highly effective material for boll weevil control and that encapsulated methyl parathion, bifenthrin and endosulfan also are effective in causing high mortality.

Last Modified: 11/28/2014
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