Effect of temperature on toxicity of three pyrethroids to horn flies.
Predictive models describing best-fit regression equations for per cent mortality of horn flies as a function of temperature were determined for each of three pyrethroid insecticides (fenvalerate, flucythrinate and permethrin) over the temperature range 20-35 degrees C. Susceptible horn flies, Haematobia irritans (L.), were exposed to c. an LC70 dose of each pyrethroid using a residue-on-glass method. This technique used confined exposure in chambers with temperatures of 20, 25, 30 and 35 degrees C. Within this range, mortality was greatest at 25 degrees C with all three insecticides. Estimated temperature-mortality equations for each pyrethroid revealed different responses of horn flies to each of these insecticides. Horn flies exposed to flucythrinate demonstrated a linear mortality response that varied inversely with temperature. The response to permethrin was described by a quadratic equation, while the response to fenvalerate was best fitted by a cubic equation.
Hinkle
N C
NC
Department of Entomology, University of Georgia, Tifton 31793.
Sheppard
D C
DC
Bondari
K
K
Butler
J F
JF
D000818:Animals; D005260:Female; D007306:Insecticides; D009117:Muscidae; D009570:Nitriles; D026023:Permethrin; D010648:Phenylacetates; D011722:Pyrethrins; D011897:Random Allocation; D013696:Temperature
D007306:Insecticides; D009570:Nitriles; D010648:Phenylacetates; D011722:Pyrethrins; D026023:Permethrin; C027975:flucythrinate; C017690:fenvalerate