摘要 : Side effects of two commercial neem products, NeemAzal-T/S (1% azadirachtin) as foliar application and NeemAzal-U (17% azadirachtin) as soil application were tested in laboratory bioassays against about-to-emerge adults and adults... 展开 Side effects of two commercial neem products, NeemAzal-T/S (1% azadirachtin) as foliar application and NeemAzal-U (17% azadirachtin) as soil application were tested in laboratory bioassays against about-to-emerge adults and adults of an aphelinid, <i>Eretmocerus warrae</i> (EW) an efficient parasitoid of the whitefly <i>Bemisia tabaci</i> (WF) in Thailand. Hatching rates of unparasitised WF were reduced by foliar treatments with NeemAzal TS from 84% (control) to 16% (10 ml l^-1), by soil application with NeemAzal-U from 84% (control) to 63% (3.0 g l^-1). Parasitoid emergence was affected in a dose-dependent manner. Whereas 80% of the EW adults hatched in tap-water treated controls after foliar treatments of pupa with NeemAzal-T/S hatching rates decreased to 50 and 24% at 5 and 10 ml l^-1 dose rates respectively. In contrast, the soil application of NeemAzal-U did not affect the emergence of parasitoids. In both neem treatments longevity of the hatched adults was the same for both sexes, and no alternation in sex-ratio was detected. The longevity of the adult parasitoids was only affected after 36 hrs contact with high dose residues of NeemAzal-T/S (10-15 ml l^-1) in a dry-residue bioassay test. The experiments indicate that ecto-endo parasitoids are principally highly vulnerable to neem but show in addition that soil application could reduce negative side effects compared to plant spraying and hence improve selectivity. 收起