Abstract
The results of the recent study showed that the host kind and larval instars exhibit a varying response to the insects growth inhibitors ( Buprofezin . Cyromazin and Lufenuron ). And the 1st and 2nd larval instars were more susceptible than the rest larval instars to the insects growth inhibitors the highest toxicity to the 1st and 2nd larval instars reached on casher obtained from Lufenuron and 1st Lc50 reached 0.5% in comparison to Cyromazin and Buprofezin Lc50 values 0.7 and 0.6% respectively the highest relative toxicity value reached 100% for Lufenuron and Cyromazin for the 1st and 2nd larval instars reared on cashew respectively . and the lowest relative toxicity value was obtained from treating 3rd larval instars reached on almond with Lufenuron which reached 27.77 . The highest relative efficiency value reached 36% from treating the 1st and 2nd larval instars reared on cashew by Lufenuron followed by 214.28% for Cyromazin when applied on the same larval instars reared on Pistachio . The lowest relative efficiency value 100% obtained from treating the 3rd larval instars reared on Pistachio by Lufenuron and the 4th larval instars reared on Pistachio by Cyromazin.
