All the life stages of the reduviid predator Rhynocoris marginatus (Fab.) were released (30, 50 and 70 Days After Seedling Sowing -DAS) into the groundnut field at 5000/hectare. Spodoptera litura (Fab.), Helicoverpa armigera (Hubner), Atractomorpha crenulata, Chrotogonous trachypterus, Aphis craccivora, Mylabris pustulata and
Mylabris indica were observed during the study period. R.marginatus significantly reduced S.litura(85.89%) followed by H.armigera(67.65%), A.craccivora(46.34%)and A.crenulata and C.trachypterus (42.86%). R.marginatus had no impact on the Mylabris spp. populations observed during the study period. R.marginatus not
affect the other predatory fauna such as coccinellids (Menochilus sexmaculatus Fab., Coccinella septumpunctata ) praying mantis, wasp, damselfly (Agriochemis feminafemina Braucer ) and spiders (Lycosa tista Tikader and Hippasa pisaurina Pocock)found in the control and predator released field. Maximum production of groundnut was observed in the predator-released field (1480 Kg/hectare) than the sole crop (1104 Kg/hectare) and the results
were statistically significant. Similarly, the net gain and the cost benefit ratio were also the highest in the R.marginatus released groundnut field.
