Pak. J. Agri. Sci., Vol. 44(2), 2007 MORTALITY RATES OF FIVE COMMERCIAL INSECTICIDES ON CHRYSOPERLA CARNEA (STEPHENS) (CHRYSOPIDAE: NEUROPTERA) Abida Nasreen, Muhammad Ashfaq, Ghulam Mustafa and Rashid Rasool Khan University College of Agriculture, Bahauddin Zakariya University, Multan, Pakistan Department of Entomology, Univesity of Ariculture Faisalabad, Pakistan. The green lacewing Chrysoperla carnea (Stephens) (Chrysopidae; Neuroptera) is a generalist biological agent commonly used to control insect pests. Toxic effects of five commercial insecticides viz., carbosulfan, leufenuron, cyfluthrin, methomyl and fenpropathrin were evaluated on green lacewing through laboratory bioassays. At 27 ± 2°C, 65 ±10% RH and 14-h photophase. Insect mortality was determined following insecticide exposure by eggs immersion, larval leaf dip bioassay and by direct adult topical application. Larval mortality was observed for the instar treated and for following instars and pupae. Following insecticide exposure, C. carnea mortality was greatest for life stages treated directly and decreased during subsequent life stages. Methomyl, cyfluthrin and fenpropathrin caused about 95% mortality when 1 st instar was exposed to chemicals. Methomyl and fenpropathrin remained effective and caused 92% mortality when 2 nd instar was exposed to chemicals. All chemicals caused about 60-70% mortality, when applied to 3 rd instar. Mortality of adults was highest 57% for fenpropathrin. All materials had greatest effect on longevity and fecundity of adults. Key words: Chrysoperla carnea, insecticides, neuroptera, mortality, egg, larvae, adult, fecundity, longevity. INTRODUCTION Biological control agents can cause substantial decrease in pest population numbers (Hassell, 1978). Green lacewing is a generalist and widely distributed predator of many soft bodies insect pests (Geetha and Swamiappan, 1998; New, 1975). Pest management revolution illustrated in the history of biological control in temperate glass houses (Hussey, 1985) can further confirm their importance. Being an entomophagous predator in many crops, with wide use in biological control in glasshouse crops and its ability to be easily reared in large numbers, the common green lacewing, Chrysoperla carnea (Stephens) is taken as a representative of Chrysopidae (Greve, 1984; Morrison, 1985) to be used in biocontrol program. However, pesticides are also used in modern agriculture, as biological control alone most often does not solve all pests and disease problems. Combining biological control with pesticide use was the cornerstone on which the concept of integrated control was founded (Perkins and Garcia 1999), insecticides such as organophosphates, carbamates, and synthetic pyrethroids are generally highly toxic to biological control agents, due to their broad spectrum of activity (Croft, 1990). Other insecticides that do not appear to kill natural enemies, may also have sub-lethal effects, such as altered behavior, reduced reproduction, and reduced longevity, on natural enemies (Jacobs et al., 1984; Elzen, 1989; Croft, 1990; Longley and Jepson, 1996). Croft and Brown (1975) reviewed that indiscriminate use of pesticides not only results in the development of insecticide resistance but also eliminates the natural enemies of insect pests. Therefore, it is important to examine the possible disruptive effects of candidate insecticides on beneficial insects, and to determine the insecticides compatible with key biological control agents (Stapel et al., 2000). The most crucial requirement for pesticides is that they must be compatible with biological control. Therefore, only those pesticides should be used that are most selective and which have no adverse effects on beneficial organisms (Hassan, 1989; Cross and Dickler, 1994). In IPM. The compatibility of an insecticide with biological control agents is often examined by tests screening for mortality of natural enemies, but sub-lethal effects on beneficial insects are largely overlooked (Elzen, 1989). The increase in knowledge is the basis for reducing the undesirable effects of pesticides applications, which among others, is an important principle of integrated production (Cross and Dickler, 1994). Many workers have revealed the importance of C. carnea in biological control and the inevitability of chemicals to be applied in synchronization as a prerequisite of IPM. The purpose of work reported here was to evaluate effects of the pesticide on eggs and larvae of C. carnea that could help to find compatible predator life stage with selected insecticides and vice versa. MATERIALS AND METHODS The experiments were conducted under laboratory conditions at 27 ± 2°C and 60 ± 5% RH and 14-h photoperiod, in Insect Rearing laboratory of University College of Agriculture, Bahauddin Zakariya University Multan. Table 1. outlines the five commercial insecticides tested at this work and their distributors. All solutions were prepared in distilled water by serial dilution for 266