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Monday, 18 November 2002
D0029

This presentation is part of : Student Competition Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology

Effect of temperature on efficacy of spinosad for managing differential grasshopper in leafy green vegetables

Kaushalya Amarasekare and Jonathan V. Edelson. Oklahoma State University, Department of Entomology and Plant Pathology, 127 Noble Research Center, Stillwater, OK

Spinosad is a fermentation derived insect control agent and belongs to the newest class of insecticide spinosyns. It is a product of fermentation metabolites of soil actinomycete Saccharopolyspora spinosa with a mixture of macrolides molecules spinosyn A and D. Leafy green vegetables, which are grown for fresh or processing markets in south central United States, are exposed to a range of temperatures varying from 35C to 5C according to the time they are grown. Grasshoppers are important insect pests of leafy green vegetables that feed on leaves and contaminate the final product. This study was conducted to evaluate activity of spinosad (SpinTor 2SC) at four different temperatures (10C, 15C, 25C and 35C). The differential grasshopper Melanoplus differentialis (Thomas) (Orthoptera: Acrididae) was used in the study. Individual third instar nymphs were starved for 24 hours and then provided with a collard (Brassica acephala) leaf treated with spinosad. Grasshoppers with leaf tissue were placed in environmental temperature chambers that were randomly assigned a temperature regime. After 48 hours the treated leaves were replaced with untreated leaves. Efficacy of insecticide was measured as mortality of grasshoppers. Results indicate that efficacy increased with increasing temperature indicating a positive temperature coefficient for spinosad.

Species 1: Orthoptera Acrididae Melanoplus differentialis (Differential grasshopper)
Species 2: Capparales Brassicaceae Brassica acephala (Collard)
Keywords: temperature, spinosad

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