Effect of Pesticides on Mortality, Fecundity, and Egg Viability of Geocoris pallens (Hemiptera: Lygaeidae)

Abstract

Sublethal doses of the insecticides carbaryl, methidathion, and methomyl, the acaricides dicofol and propargite, the herbicide glyphosate, the defoliant DEF, and the fungicide sulfur were tested as cotton leaf residues on Geocoris pallens Stal. All pesticides except propargite did not significantly increase adult mortality 25 to 192 h after a 24 h acute exposure; neither did they have any detrimental effect on female mortality, fecundity, or egg viability. These results suggest that deleterious long-term effects in predator populations would not occur if insects survived initial treatments. Adult males were more susceptible to methidathion and methomyl, and adult females were more susceptible to propargite. Females exposed to DEF laid more eggs, and females exposed to glyphosate and methomyl laid more viable eggs. Potential beneficial effects of chemicals on predator populations should be considered in the selection of pesticides for pest management programs.