Rainfastening of bifenthrine to cotton leaves with selected adjuvants

Abstract

There are thousands of adjuvants on the market, yet little is known about their effects on the activity of insecticides on plant surfaces. The effects of 11 selected adjuvants on the rainfastness and retention of bifenthrin ([lάJά-(Z)-(±)-(2 methyl[l,l'-biphenyl]-3-yl) methyl 3-(2-chloro-3,3,3-trifluoro-l-propenyl)-2,2-dimethylcyclopropanearhoxylate) on cotton (Gossypium hirsutum L.) leaves were investigated. In addition, the effect of the adjuvant Bond on the efficacy of bifenthrin and a Bacillus thuringiensis (Berliner) formulation was determined. Bifenthrin mixed with each adjuvant was applied to greenhouse grown cotton plants using a spray chamber. Simulated rainfall of 13 mm was then applied to treated cotton plants at 0.25, 1, and 4 h after treatment. Bond and Agimax-3 were the only adjuvant. to significantly increase the rainfastness of hifenthrin on cotton leaves. Agri-Dex, Soy-Dex, and Dyne-Amic significantly decreased the rainfaqtness of bifenthrin. In tests conducted with an immersion cell apparatus, Orchex 7% resulted in twice the retention of Agri-Dex, the nkit highest retained adjuvant. Both petroleum and veget-able oils enhanced retention of bifenthrin on the leaf surface. Bond mixed with bifenthrin md a B. thuringiensis formulation did not reduce the activity of these insecticides against tobacco hudworm (Heliothis virescens) and soybean looper (Pseudoplusia includens) larvae. Retention on the leaf may he related to spread and to the degree of binding of the insecticide to the surface by properties of the adjuvant. Yet, the properties of Agri-Dex that enhanced the retention of bifenthrin to the cotton leaf decreased its rainfastness.

Citation

Mulrooney, J. E.; Elmore, C. D. 2000. Rainfastening of bifenthrine to cotton leaves with selected adjuvants. Journal of Environmental Quality 29(6): Nov. - Dec., Madison, WI.