efficiency and pradatory of oenopia conglobata contaminata (menetries) feeding on green peach aphid myzus persicae (sulzer) under laboratory conditions

the green peach aphid,myzuspersicae  (hem:aphididae) is a polyphagus aphid species that infects over 400 plants species belonging to 40 different families. the oenopia conglobata contaminata  (col.: coccinellidae) is one of the most important predator of orchard pests in iran. in this study, efficiency and predatory of this predatoron green peach aphid m.persicaewas evaluated under laboratory conditions (55±5% r.h. and a 16:8 h photoperiod). the effect of host accumulation to amount of reproduction of this ladybird was studied for 21 days. the result showed that accumulation of 40 hosts was regarded as the lowest density that the ladybird will be required to grow. data were analyzed with sas statistical software.logistic regression was used to determine type of functional response and nonlinear regression to estimate parameters of searching efficiency (a) and handling time (th).the result showed that the functional response was type ii. searching efficiency and handling time were 0.063±0.00819 h-1 and 0.1425±0.029 h, respectively. predation rates of forth instar, male and female were 45.22, 29.65 ,50.70 respectively. our results indicated that the o. conglobata  may be a useful candidate for the biological control of m.persicae.