Feeding potential and cost of production of green lacewing, Chrysoperla carnea (Stephens) on alternate hosts

Significantly high cocoon weight was observed when T. castaneum larva was provided as larval food (I generation-12.50±0.19, V generation-8.88±0.30 mg), while lowest on the eggs of Cadra cautella and C. cephalonica and values were statistically at par. Highest growth rate index was recorded in larvae fed with T. castaneum larvae (I generation-142.86, V generation-118.40) although pupae were also preyed by the predator. The cost of production of 1,000 eggs of the predator was worked out to be Rs.7.16, Rs.3.68 and Rs.7.06 on C. cephalonica eggs, T. castaneum larva and D. melanogaster larva, respectively. Lower production cost of eggs of C. carnea, when larvae were fed with T. castaneum larvae, was due to less amount of larval diet required, low mortality during developmental stages and emergence of highly fertile adults. These studies clearly indicate that T. castaneum was found to be suitable alternate host against the factitious laboratory host, C. cephalonica for commercial production of the predator.