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Temperature had various effects on the predacious efficacy of immature and mature stages of the coccinellid predator, Stethorus punctillum on the two-spotted spider mite, Tetranychus urticae. In the case of immature stages, food consumption at the lowest tested temperature (158C) was significantly higher than that at higher temperatures (25 and 358C). On the contrary, positive correlation between food consumption and temperature was evaluated in the case of adult predator. Regarding predator responses to different prey density, a high positive correlation between food consumption and prey density was evaluated among 4 th instar larvae of the predator, followed by adult predator, while younger instars did not show reasonable increases with increasing prey densities. These results confirm that larval and adult stages of S. punctillum exhibit ''Type II'' functional response. In conclusion, the 4 th instar larvae and adult predator are the most preferable stages in winter and summer crops to control T. urticae, respectively.

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The present work was carried out to study the biological aspect of B. brevicornis when reared on different hosts (Ephestia kuehniella, Galleria mellonella, Corcera cephalonica, Sesamia cretica, Spodoptera littoralis and Pectinophora gossypiella). Our Results assured that the type of host had great impact on the durations of the immature stages and longevity of the parasitoid. The highest & lowest incubation periods were when reared the parasitoids on Pectinophora gossypiella (45.75±1.4hours) and E. kuehniella (39.87±0.95 hours) respectively, the difference was insignificant at the other hosts. Duration of larval stages was significant shorter when parasitoid reared on S. cretica (1.86±0.079 days) than the rest hosts. The longer pupation period was recorded when parasitoid reared on Pectinophora gossypiella (7.6±0.13 days), but was insignificant on the other hosts. The highest duration period of immature stage was when reared B.brevicornis on P. gossypiella (12.75±0.74 days) but insignificant difference when reared on G.mellonella [ 9.16±0.22 days ] and S. cretica [ 9.91±0.14 days ]. The mean duration of male longevity of parasitoids was longer when reared on E. kuehniella (15.73±0.73 days) and shorter when reared on C.cephalonica (11.75±0.51 days). The mean duration of female parasitoids was highest when reared parasitoids on S. cretica (19.6±0.51 days). The total number of eggs laid per female of B.brevicornis during its life span was highest on Galleria mellonella (268.88±19.65 eggs), and lowest on C.cephalonica (78.1±10.63 eggs). A percentage of eggs hatchability was significantly lowest when reared on S. littoralis (0.09±0.02642 %) than when reared on the other hosts, while percentage of emergence was insignificantly different when reared on Sesamia cretica (87.36±3.92 %) and Pectinophora gossypiella (87.02±3.85 %).

During 1996 and 1997, populations of aphids and whiteflies and their parasites were studied in plastic greenhouses under a chemical control program and in those free of pesticides. In the greenhouses free of pesticides, the parasite A. colemani destroyed 14.7 % of the aphids. B. tabaci had no effect on the cucumbers during the spring cultivation. However, it attacked the autumn cultivation. The parasite E. mundus killed 30 % of these nymphs. 
The parasite A. colemani parasitized up to 10 % of aphids on tomato plants in greenhouses free of chemical pesticides. The parasite E. mundus killed 15.7 % of whitefly nymphs. 
In greenhouses under a chemical pesticides program, aphids and whiteflies were found on the plants at the end of the plantation season, after the pesticide spraying had stopped. Although the pest population was low, the parasite A. colemani parasitized 8 % of the aphid population. Whiteflies were not found on tomato plants in greenhouses under extensive pesticides use.