Impact of morphological traits in isogenic cotton lines on consumption-utilization indices of spotted bollworm Earias vittella (Fab) larvae

Abstract

Consumption-utilization indices of fourth instar Earias vittella larvae on five cotton isogenic lines viz., okra leaf, frego bract, nectariless, red pigmented and glandless were evaluated at a constant temperature of 30 ± 1°C, 70 ± 5% RH and a photoperiod of 16 : 8 L : D. The relative growth rate was more on glandless (0.59) and okra leaf (0.59) and less in red pigmented (0.51). The assimilation efficiency was highest on red pigmented (71.54%) followed by H-777 (70.92%) and lowest on glandless (65.97%). The relative consumption rate was more on nectariless (11.68) followed by H-777 (11.58) and less on frego bract (10.63). The efficiency of conversion of digested food (ECD) and ingested food (ECI) was maximum on glandless (8.56; 5.57) and minimum on red pigmented (6.80; 4.74), respectively. Considering the high total food consumption, growth rate, consumption rate, ECD and ECI of E. vittella, glandless was the most suitable line followed by H-777 whereas frego bract was the least suitable line.