Insecticidal Activity, Growth Inhibitory and Biochemical Effects of Plant Lectins and Bacillus thuringiensis var. kurstaki against the Pink Bollworm, Pectinophora gossypiella

El-Deeb, Dalia A.

doi:10.21608/asejaiqjsae.2021.144238

Insecticidal Activity, Growth Inhibitory and Biochemical Effects of Plant Lectins and Bacillus thuringiensis var. kurstaki against the Pink Bollworm, Pectinophora gossypiella

Document Type : Original Article

Author

Dalia A. El-Deeb

Central Agricultural Pesticides Laboratory, Sabahia Station, Alexandria Egypt.

10.21608/asejaiqjsae.2021.144238

Abstract

Insecticidal activity and sublethal effects of white kidney bean and soybean lectins compared to Bacillus thuringiensis var. kurstaki were evaluated against pink bollworm (PBW), Pectinophora gossypiella (Saunders). The in vivo effects of these lectins on the total proteases and α-amylase activities of PBW were also carried out. Results revealed that, B. thuringiensis (LC₅₀ = 61.7 and 36.1 µg / g diet) was approximately 4.7 and 4.8 times more toxic than kidney bean lectins (LC₅₀ = 289.2 and 175.0 µg / g diet) and 2.2 times more toxic than soybean lectins (LC₅₀ = 134.3 and 81.2 µg / g diet) after 5 and 6 days of treatment on the 2^nd instar larvae. The LC₂₅ equivalent concentration of B. thuringiensis and soybean lectins achieved the highest reduction of larval weight (11.9 and 13.0 mg / larva compared to 27.1 mg / larva in control) after 9 days of treatment. While kidney bean and soybean lectins at LC₁₀ and LC₂₅ increased the average time to pupation of PBW, B. thuringiensis at LC₂₅ decreased the average time to pupation compared to control. All treatments significantly decreased the pupal mean weight and adult emergence rates compared to control. Kidney bean lectins, soybean lectins and B. thuringiensis at LC₂₅reduced the average number of eggs laid / female (fecundity) to 35.2, 31.5 and 34.5, respectively, compared to 89.0 in control. In addition, %egg hatch (fertility) significantly decreased to 53.8, 51.7 and 49.1% in kidney bean lectins, soybean lectins and B. thuringiensis LC₂₅ treatments compared to 93.0% in control. Kidney bean and soybean lectins inhibited the activity of total proteases and α-amylase. Results of the present study suggest that kidney bean and soybean lectins can be used as suitable alternatives for B. thuringiensis in integrated management programs of pink bollworm.