Cold storage can extend shelf life of parasitoids for use in biocontrol. However, cold storage may have negative impacts on life history traits of the parasitoids and, therefore, on their performance as biocontrol agents. Here, we examine the effect of cold storage on life history traits of Habrobracon hebetor (Say) (Hymenoptera: Braconidae), a parasitoid of several economic lepidopteran pests. Newly emerged wasps were stored at three constant temperatures (3°C, 5°C, 7°C) for up to 4 wk. Both temperature and exposure time significantly affected longevity, parasitism, fecundity, and sex ratio. Significant reduction in longevity was observed at 3°C and 7°C, whereas longevity of wasps stored at 5°C remained stable up to the second week and then gradually decreased in Weeks 3 and 4. Parasitism rate also significantly decreased after cold storage at 3°C, 5°C, and 7°C (ranked from high to low). Fecundity decreased at T 3°C and T 5°C but this trait was not affected by storage at T 7°C. A significant shift in male production was observed at T 5°C in Week 3, but in Week 4, the only treatment with male biased reproduction was T 3°C. These results show that the effect of temperature and exposure time in cold storage is trait dependent. Overall, storage at 5°C for a period of 3 wk least impacted most life-history traits of H. hebetor wasps.

Biology, morphology and oviposition behavior of Anagrus atomus (Linnaeus), an egg parasitoid of the grape leafhopper Arboridia kermanshah Dlabola in Isfahan, Iran, were investigated. Adults were smaller than those so far reported from other regions. Females continuously drummed on plant surfaces with their antennae to search for host eggs. Parasitoid eggs hatched 2-3 days after oviposition, and A. atomus had two larval instars. First instar larvae were sacciform and immobile. Second instar larvae appeared 4 days after oviposition and were very active, and doubled their body length. The prepupal and pupal stages lasted for 1 and 5-6 days, respectively. Adult emergence began 16 days after oviposition, and peaked on day 17.

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The cotton aphid, Aphis gossypii (Glover) (Hemiptera: Aphididae), is a key pest of cucurbits in Fars Province, Southern Iran and is managed with repetitive applications of insecticides such as imidacloprid. Recently, reports of insecticide control failures have increased, particularly with imidacloprid. In present work susceptibility of two A. gossypii populations to imidacloprid and effects of possible synergist, Triphenyl phosphate (TPP), Diethyl maleate (DEM) and Piperonyl butoxide (PBO) were checked using micro-applicator bioassay. The resistant population was collected from cucumber host plant in greenhouse and susceptible population had been reared under greenhouse conditions on Cucumis sativus L. cv. Negin (Cucurbitaceae) for two years. A resistance to imidacloprid with resistance ratio of 11.24 was found in resistant population compare with the susceptible population. Combination of in vivo differential synergism studies and biochemical assays (esterase, GSTs, cytochrome P450 monooxygenase and heme peroxidase assay) suggest that the enhanced cytochrome P450 activity is the primary mechanism of increased resistance in these populations.

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