Biocontrol efficiency of Rhynocoris fuscipes (Hemiptera: Reduviidea) against Dydercus koenigii (Hemiptera: Pyrrhocoridae) a severe pest of Abelmuschus esculents

An attempt was made under laboratory condition to estimate the functional response of fourth instar of R. fuscipes to different prey densities (1, 2, 4, 8 and 16) of D. koenigii. Fourth instar of this predator showed a curve linear functional response against first nymph of D. koenigii. The prey consumed ratio (y) of R. fuscipes was increased as the D. koenigii densities(x) increases from one D. koenigii/ R. fuscipes to 16 D. koenigii / R. fuscipes. The maximum predation rate was restricted to the maximum D. koenigii number (3.9). The predation attack ratio (y/x) at less prey density categories was highest. Searching time (Ts) and attack ratio (y/x) were decreased with the increasing prey density. The fourth instar of R. fuscipes showed curve linear functional response curve when offered with different prey densities. The killing efficiency was higher at nymphal stage.