Functional Response of Chrysoperla carnea Stephen (Neuroptera: Chrysopidae) Fed on Cabbage Aphid,Brevicoryne brassicae (Linnaeus) under laboratory conditions

Functional response study of chrysoperla carnea stephen (neuroptera: chrysopidae) larval instars fed on cabbage aphid,brevicoryne brassicae (linnaeus) was carried out under laboratory conditions at 28±1-c,with 65±5% r.h and 16:8 l: d photoperiod. the prey densities used for 1st instar larvae were 10,15,20,25 and 30 (2nd - 3rd) nymphal instar aphids,while for 2nd instar larvae the used prey densities were 10,20,30,40 and 50 and for 3rd instar larvae the used prey densities were 15,30,45,60 and 75 aphids. results showed that increase in the prey density resulted in increased consumption of prey up to certain limit in the 1st,2nd as well as in the 3rd larval instar stage of c. carnea. the recorded highest consumed prey number were 22,24 and 45 for the highest prey densities of 30,50 and 75 in the 1st,2nd and 3rd larval instar stage of c. carnea. same trend was also recorded for searching,handling and resting time in all the three larval instar stage of c. carnea. the potential regarding the consumption rate of the 3rd instar larvae of the c. carnea was found higher than that of the 1st and 2nd ones. also results showed lower searching time,handling time and resting time in the first instar larvae followed by an increase in the 2nd and 3rd instar larval stage of c. carnea. results of this study also showed that the larvae of c. carnea,especially the 3rd instar had a good predation potential in preying of b. brassicae. therefore,by including c. carnea in control programs the use of the pesticides against this pest will be minimized.