稻飞虱寄生性天敌两索线虫田间制约因素的研究

通过异地多点调查和室内测定,分析稻飞虱寄生性天敌两索线虫Amphimermis sp.成虫的田间基数、垂直分布和活力的制约因子。结果表明:①土壤墒情是两索线虫成虫期的主要影响因素。黑墒条件下,成虫基数高、活力强,垂直分布趋向0—10cm耕作层;②免(少)耕和稻茬后越冬作物种植种类对成虫的影响因地而异;③在土壤pH5.45—7.32范围内,两索线虫成虫适宜生活于黑墒偏酸性土质;④尿素、碳酸铵和硫酸铵对成虫有很强的刺激性和不同程度的致死作用,碳酸铵作用最强;⑤三唑酮等11种药剂对成虫无可见影响,杀虫双等其它10种化学农药则有不同程度的刺激性和致死作用;⑥比较测定杀虫双等9种农药对两索线虫成虫的LC_(50)。

ON THE FACTORS RESTRICTIVE TO MERMITHID NEMATODE OF PLANTHOPPERS IN RICE FIELD

Based on multi-location investigations and indoor observations, the restrictive factors to the field density, vertical distribution and activity of adult parasitic nematode Amphimermis sp. , one of the main parasites of planthoppers, were explored. The results showed that; (1)the soil moisture was the determinative in its adult stage,under 20% -25% moisture content condition ,high density adult occurred with vigour and tended to 0-10 cm topsoil; (2) the effects of the kinds of overwintering crops growing after rice in no-/less- till rice field were inconsistent in different locations; (3) as the soil pH value ranged from 5. 45 - 7. 32,the adult was partial to weak acid soil; ( 4 ) urea, ammonium carbonate, ammonium sulphate, and a number of chemical pesticides such as butachlor, nitrogen, goal ,carbofuran, etc. were disadvantageous and with lethal actions of varying degrees to adult nematode, while triadimefon , carbendazim , validamycin, MCPA, chlorsul-furon, buprofezin, paclobutrazol, ethofenprox, brocythrinate. methamidophos and Bt preparation were all safe; (5) the LC50S of nine pesticides to adult were determined.