Evaluation for Antibiosis Resistance in Cotton to Helicoverpa armigera Larvae

Abstract

The antibiotic effect of the new cotton lines, NR1, NR2, NR3, NR4 and NR5 and the control, SR3, on selected developmental parameters of the 2^nd instar Helicoverpa armigera larvae was investigated. The larvae were fed on four diet types of each variety/line: fresh leaf, fresh square, artificial
diet mixed with lyophilized powder of leaf and artificial diet mixed with lyophilized powder of square. RCB design was employed with four replicates. Each replicate had 10 diet cups of each variety/line with one larva. The results showed that the larval and pupal weights and the adult longevity of larvae reared on all diet types from NR1 were significantly lower and the larval period was significantly longer than those from SR3. The larvae produced on 4 diets from the other tested lines were found to have only some parameters significantly differed from the control. Fresh leaves/squares had better antibiotic effects on the bollworm development than the mixed diet with dried parts.