FEEDING RESPONSE, BIOLOGICAL AND TOXICOLOGIGAL POTENTIAL OF SOME IGR's ON S. LITTORAL'S

Document Type : Original Article

Authors

1 Department of Entomology, Faculty of Agriculture, Zagazig University, Egypt

2 Plant Protection Research Institute, Agricultural Research Centre, Dokki, Giza, Egypt

Abstract

Three new insect growth regulators namely, Diafenthiuron, Bu-profezin, and pyriproxyfen were evaluated against S..littoralis, 4th instar larvae. Larvae were fed on castor bean leaves treated with 500 ppm so‌lutions of the IGRs using dipping technique. Results obtained were sum‌marized as follows : 1- Feeding response Pyriproxyfen increased the feeding response (1 8.5%), diafenthiu‌ron revealed great reduction in areas consumed (33.3%), and buprofezin treatment showed a slight reduction for the food response (7.4%). 2-Larval mortality : After 2 days of treatment, the IGR compounds were not effec-tive, the mortality of larvae began after three days, and after 7 days were 31,24,28, and 6% for diafenthiuron, buprofezin, pyriproxyfen and control respectively. 3-Pupation and adult emergence : IGR compounds revealed nearly the same degree of effect on the Percentage larval pupation which reached 54,57 and 54% in case of dia‌fenthiuron, buprofezin and pyriproxyfen respectively, while it was 85% in control. Pyriproxyfen was the most effective IGR in decreasing adult emer‌gence followed by buprofezin adn diafenthiuron, they resulted in 59,69.9 and 79.5% emergence respectively, while it was 88.2% in control. Pyriproxyfen was the most effective IGR in producing deformed pupae (23.4%) followed by buprofezin (12.4%) and diafenthiuron (1 1 .4%). The percentage of control was (2.5%). The percentages of malformed adults were 9.7, 1 9.7, 16.6 and 3.8% for diafenthiuron, buprofezin, pyriproxyfen and control respective‌ly. 4-Effect on fertility and biotic potential : Buprofezin revealed the highest reduction in the number of eggs laid per female (335 eggs) followed by Pyriproxyfen (666 eggs) and Dia‌fenthiuron (1140 eggs) in comparison with the control (1259 eggs).