1Regional Research Station, Orissa University of Agriculture & Technology, Keonjhar-758 002, Orissa (India).
2Department of Entomology, College of Agriculture, Orissa University of Agriculture & Technoology, Bhubaneswar-751 003, Orissa (India).
*A part of approved Ph.D. thesis submitted by H.P. Patnaik to the Orissa University of Agriculture & Technology, Bhuhaneswar-751 003, Orissa (India).
The magnitude of acidity in the leaf extracts and its influence on the incidence of Heliothis armigera (Hub.) in 13 desi (local) early maturing chickpea cultivars were studied at the Regional Research Station, Keonjhar (Orissa) during 1989–90 and 1991–92 crop seasons. The egg and larval counts were negatively correlated with increasing concentrations of acid exudates in the leaf extracts of the test cultivars. Low density of eggs (0.7 to 1.6/10 plants) and larvae (3.0 to 4.0/10 plants) were associated with high acidity (24.2 to 25.3 milliequivalent) in the cultivars, viz., PDE 2–1, PDE 2–3, PDE 3–2 and PDE 7–2. While the cultivars, PDE-5-3 and Annigeri-1 with low acid contents (13.5 to 15.1 milliequivalent) in their leaves harboured more eggs (≥ 2.7/10 plants) and larvae (≥ 5.9/10 plants). Under the field conditions of north Orissa, the cultivars, viz., PDE 3–3, PDE 7–2, PDE 7–3, ICC 506 and Annigeri-1 were identified as moderately resistant to H. armigera and showed a resistance/susceptibility ratings of 3.0 to 5.0 on 1–9 scale. However, the resistance expressed by certain cultivars viz. PDE 3–3, PDE 7–3 and ICC 506, was attributed to the factors other than acidity while that of PDE 7–2 appeared to be due to high acidity (25.3 milliequivalent).
