Date: 3/30/99

Time: 3:10

Type: Symposium

Number: 154

Adjuvants for enhancing residual activity of SLAM

*M.R. McGuire, R. Behle, USDA-ARS, Peoria, IL and S. Johns, MicroFlo Corp., Sparks, GA
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Slam is the only cucurbitacin bait currently marketed for controlling adult corn rootworms. While the bait provides effective knockdown, residual activity has sometimes suffered leading to retreatment of fields for newly emerging or migrating adults. Currently two formulations of Slam exist; one is called Prader and the other SD. Prader is the type most commonly used but the SD formulation is cheaper and easier to manufacture. However, in previous tests, problems were observed with SD and this formulation was pulled from the market. Our objective was to determine if polymer-based adjuvants could effectively prolong the residual activity of the SD formulation in the field. Gluten and lignin are naturally occurring polymers that provided rainfastness and solar stability for microbial pesticides. When tank mixed at relatively low rates, the polymers in the resulting spray droplet will crosslink on the leaf surface, thus rendering the deposit rainfast. Field corn was treated aerially with SD containing one of four adjuvant treatments: 2% lignin, 3% lignin, 0.5% gluten or 1% gluten. Rootworm populations were monitored for three weeks after application with yellow sticky traps. SD without adjuvant and SD + 3% lignin did not control adults as well as SD with either gluten rate or SD with 2% lignin. The 3% lignin also caused mixing and application problems.

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