Functional response of mealybug ladybird, Cryptolaemus montrouzieri (Col.: Coccinellidae) on Planococcus ficus (Hem.: Pseudococcidae)

One of the parameters used in natural enemies evaluation is functional response studies to predict the efficacy of the predator in biological control programs. The vine mealybug, Planococcusficus (Signoret) is an important vineyard pests in all parts of the world. Cryptolaemusmontrouzieri Mulsant, is a well–known natural enemy of mealybugs. The experiment was conducted under laboratory condition with 26±1°C with 70±5 % RH and 12:12 D:L photoperiod with four densities of adult females of vine mealybug, P. ficus, as host insect. Adult female and male and 3rd instar larval stage of C. montrouzieri and four densities (3, 5, 7 and 9, each with 10 replicates). The number of host killed after 24 hours were recorded. Determination type of functional response model and estimation of related parameters were carried out based on two–stage analysis method by using SAS software. A type 2 functional response was concluded under this experimental condition for all stages of predator using logistic regression with parameters estimated through nonlinear regression. The results for searching efficiency and handling time for 3rd instar larval, adult male and adult female of the predator were (0.6922 and 0.9549 hours), (0.4901 and 1.3542 hours) and (0.5977 and 1.0996 hours), respectively. Results showed that 3rd instar larvae of predator showed a better searching efficiency and lowest handling time rather than adults which is a fine character for a predator.