Impacts and evaluation of Hormoligosis of some insect growth regulators on Phenacoccus solenopsis (Hemiptera: Pseudococcidae)

Abstract

Insects when exposed to sublethal applications of pesticides exhibit hormoligosis in their various biological activities. The present research was conducted to evaluate the hormoligosis impacts of IGR’s pesticides including pyriproxyfen (Priority 10.8 EC) and lufenuron (Ardent 5 EC) on cotton mealybug in laboratory conditions at IPM Laboratory, Department of Entomology University of Agriculture. The results revealed that concentration-dependent mortality in cotton mealybug of 1st instars and adults was observed that decrease after generations at sub-lethal dilutions of Priority ® and Ardent ® pesticide which retained development of resistance from G1 to G2. Maximum hormoligosis revealed at 3 days post treatments interval (PAI) Priority ® in fecundity at LC10 (0.07%) in G5 (63.17 crawlers/female) and at 7 days Priority ® in G5 (68.13 crawlers/female). At 7 days lufenuron of sub-lethal concentration of LC10 (0.01%) in G5 (73.18). At 3rd and 7th days post treatments interval Priority® and Ardent® demonstrated maximum hormoligosis in longevity at LC10 (0.07%) in G5 (57.29, 57.14 days), (54.07, 58.10 days) respectively, and hormoligosis of sex ratio was not determined against Priority® and Ardent®. We conclude that hormoligosis development is fast at sub-lethal dilutions of Ardent and Priority® at LC10, LC20 and LC30 with respect to mortality, fecundity, and longevity. While hormoligosis development was fast at sub-lethal dilutions of priority® and ardent® at LC30, LC40 and LC50 with respect to the mortality of adult female. In Pakistan, pesticide resistance in cotton mealybug can be achieved if the effective and different pesticides are used along with other Integrated Pest Management techniques in rotation and at the early stage of resistance improvement.