toxicity and oviposition deterrent activities of exocarp and kernel of ginkgo biloba seed extracts against tetranychus urticae koch.

toxicity and oviposition deterrent activities of ethereal extracts of exocarp and kernel of ginkgo biloba seed were evaluated on various life stages of two spotted spider mite tetranychus urticae. petroleum ether was used for extraction. bioassay was conducted using three replicates for testing five concentrations 35, 45, 60, 75 and 100 g/l of pure extracts. lc50 was measured by pri-probit software. effect of extracts on various life stages of mite was measured using randomized complete block design (rcbd) with three replicates. the result indicated that extract of the exocarp and the kernel lead to mortality in various stages of mite. the most sensitive stage was nymphal stage. lowest lc50 value (39.82 mg/ml) and highest one (48.27 mg/ml) related to the exocarp and the kernel extracts, respectively. however, there was no statistical difference between effects related to extract of exocarp and kernel. these extracts reduced the oviposition to 3.5 and 4.1 eggs/day as well as the oviposition period which diminished to 8.9 and 8.1 days, which in comparison to control (9 eggs/day, 16 days) this reduction equivalent to 60% and 50%, respectively. since exocarp is removed during drug production from ginkgo seed, this production waste can be used as a source for pesticide compounds production.