Evaluation of Two Insect Growth Regulator Activities on Egg and Larvae of Earias insulana (Boisd.) (Lepidoptera: Noctuidae)

Under the laboratory conditions, toxicological evaluation of the ovicidal and larvicidal activities of two IGRs compounds; Triflumuron and Hexaflumuron against eggs or 1^st, 2^nd, 3^rd and 4^th instars larvae of Earias insulana (Boisd.). Also, some biological effects of these compounds on larvae, pupae treated as eggs were studied. In addition, some biochemical assays for protein, lipid, N- acytel-glucceamine and chitinase activity of E. insulana larvae were estimated
          The results showed that Hexaflumuron was the most toxic IGR than triflumuron against eggs and larval stages of E. insulana. Eggs (1-3 days old) treated with Triflumuron had LC₂₅ and LC_50s values(9.42 and 41.6 ppm). In contrast, It’s had appeared a high susceptibility with Hexaflumuron, the LC₂₅ value decreased to 7.3 ppm, while LC₅₀values had a highly decreased to 19.7 ppm. While treated the first and second instars larvae of E. insulana had highly susceptible to Triflumuron and Hexaflumuron compounds than 3^rd and 4^th instar larvae. All stages of E. insulana had less susceptible to Triflumuron than Hexaflumuron treatments.
           The obtained results cleared that increase in times required for larval and pupal developmental stages treated as eggs (1-3 days old) of E. insulana treatment with Triflumuron and Hexaflumuron.
           E. insulana larvae treatment with Triflumuron and Hexaflumuron had a highly reduction in the total soluble protein contents to 21.99 and 16.9 (mg/g.b.wt), respectively, compared with the control (32.5 mg/g.b.wt) with high decrease in the total lipid content that estimated by 20.6 and 14.6 (mg./ g.b.wt), respectively compared to 27.3 (mg./g. b.wt) in control. On the other hand, both of compounds occurred reduction in N- acytel - glucoseamine to 109 and 99 (µg NAGA /g. b.wt) compared to 171.5 (µg NAGA /g. b.wt) in control that led to increase the chitinase activity to 623.43 and 857.3 (µg NAGA x103/min/g.b.wt /larvae) compared to 560.2 (µg NAGA x103/min/g.b.wt / larvae) in control.