Division of Entomology, Indian Agricultural Research Institute, New Delhi-110 012 (India).
*Present Address: Associate Professor, Department of Entomology, Agricultural College, Andhra Pradesh Agricultural University, Bapatla-522 101, Andhra Pradesh (India).
The effect of diflubenzuron on chitin content and consequently on the electrical resistance in the cuticle of Schistocerca gregaria was studied. The chitin content in the forewings of treated male was 2.25, 4.69 and 5.19 mg while the electrical resistance was 29.76, 39.05 and 41.37 K.Ohms-cm2 on the 1st, 7th and 15th day after moulting, respectively. Likewise, in the untreated individuals, the chitin content was 2.56, 6.13 and 6.69 mg while the electrical resistance was 30.91, 41.59 and 45.10 k.Ohms-cm2. This suggests a gradual increase in chitin content and, in turn, electrical resistance from the time after moulting in the forewings of S. gegaria. Diflubenzuron treatment significantly reduced the chitin content as well as electrical resistance in the cuticle of treated individuals. Hence, it can be surmised that the electrical resistance of the insect cuticle is directly related to its chitin content.
