Study On The Toxicity Of The Leaf Extracts From Datura Metel Linn. To Meloidogyne Incognita Chitwood

The toxicity of the leaf extracts from Datura metel Linn. to Meloidogyne incognita Chitwood were studied in this paper. The experiments revealed that the higher concentration and the more treating time , the heavier of toxicity was abtained. The best concentration and time of treatment were 0.5% and 120h ,the corrected mortality of the second juvenile of the nematode were 92.59% and 82.98%,the middle lethal concentrations( LC50) of the nematodes was 0.0913%, the middle lethal time (LT50 ) of the nematodes was 64.14 h; The corrected suppression rate of eggs were 87.50% and 96.44%,the middle lethal concentrations( LC50 ) was 0.1286%,the middle lethal time (LT50 ) was 42.96 h.The extract could inhibit the development of the embryonic and post-embryonic of nematode. With the l%(w/v) concentration for 48h, only 19.88% eggs had completed their embryonic development, increased the abnormal eggs ;The post-embryonic development was delayed 2 days, prevented juvenile penetration for 4 days ,reduced the number of eggs.The best solvents, the best time, the best temperature, the best part of plant of extract were 2% acetone, 48h, 50℃, seed, respectively. The fresh leaf and fresh flower were less toxic than dry leaf and dry flower to the nematodes. Sun light could increase the nematocidal activity of extract. Buffer liquid and pH had little effect on the nematocidal activity of extract.Alkaloids play an important role in nematocidal activity. It suppressed the activity of AchE , could attack the nematode neural system.