Does Hot Weather Affect Insecticide Performance?
Higher temperatures and low humidities can affect insecticide performance in several ways. • The metabolic activity of insects increases as temperature increases. Enhanced metabolism may either enhance the toxic effects of the insecticide or increase insect ability to detoxify or tolerate insecticides. The toxicity of organophosphate insecticides, such as chlorpyrifos (Lorsban), Orthene, increases as temperature increases. In contrast, the toxicity of pyrethroid insecticides, such as Asana, Proaxis, Decis, Mustang Max, and Warrior, decreases as temperature increases. • Low humidity and high temperatures may cause small insecticide droplets to evaporate before reaching and penetrating the soil canopy. Evaporation may reduce insecticide control. Evaporative effects can be reduced by avoiding application during the heat of the day, increasing water volume, increasing droplet size by changing nozzles, or by adding crop oils (consult labels or companies for specific recommendations). • Whil
