Sublethal effects of insecticides on cotton aphid reproduction

Insecticides are often implicated in causing outbreaks of cotton aphids through stimulation of reproduction. In this study we report the sublethal effects of dosages of Capture, Orthene, Furadan or Knack on cotton aphid reproduction. We could not detect any increase or decrease in the intrinsic rate of increase of cotton aphids exposed to Capture, Orthene of Furadan. However, we did detect slight differences in the net reproductive rate of aphids treated with Capture justifying further investigation of the effect on reproduction by this insecticide. Trends based on simple linear regression models suggest that sublethal dosages of Capture or Furadan have a negative impact on aphid population growth as dosages increase. These data suggest that stimulation of reproduction by these insecticides may not play a major role in cotton aphid outbreaks or resurgence. Knack is a juvenoid insecticide currently used for control of whiteflies in cotton. It demonstrated significant activity towards cotton aphid in our bioassays. Knack caused sterility in most aphids exposed to dosage exceeding 1 ppm, and reduced aphid longevity by about 50%. Modifying aphid population structure and growth through the use of juvenoid insecticides such as Knack, may prove to be an effective proactive approach to pest control without adversely impacting beneficial organisms and minimizing pest resurgence.

Sublethal effects of insecticides on cotton aphid reproduction Academic Article