author(s)
Mohammad Ali Tanani and Nader Ali Bakr

abstract
The objective of current investigation was to evaluate the toxicity and developmental effects of diofenolan (10.0, 1.0, 0.1, 0.01 and 0.001 ppm) on this insect pest Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) in Physiology laboratory, department of Zoology and Entomology, Faculty of Science, Al-Azhar University during 1917. LC₅₀ values were estimated in 0.028 ppm and 0.036 ppm, after treatment of newly hatched and full grown larvae, respectively. After treatment of the newly hatched or full grown larvae with sublethal concentrations of Diofenolan, larval duration was pronouncedly prolonged and the developmental rate was drastically regressed, in a dose-dependent course. The pupation process was detrimentally prohibited, regardless the larval instar under treatment. Although diofenolan failed to exhibit a disruptive effect on the metamorphosis program (larval-pupal intermediates) after treatment of the newly hatched larvae, such program was impaired after treatment of full grown larvae, especially at the higher three concentrations. Also, the pupal morphogenesis was disturbed (pupal deformities) after treatment of larvae, irrespective of the instar under treatment.