摘要
1988年室内试验结果证明:芜菁夜蛾线虫的5个品系Agriotos、All、Mexican、NC 116、Florida对蛀干害虫小木蠹蛾幼虫有很高的侵染力;但不侵染蛹。用Agriotos品系作试验,剂量和温度影响小木蠹蛾的死亡率和致死速度。当剂量大于25条线虫/木蠹蛾幼虫时,死亡率可达92％以上,同一剂量对一年、二年生幼虫的死亡率差异不显著。在15-30℃的范围内,线虫均能侵染和杀死寄主,但30℃不能在寄主尸体内繁殖。25℃为线虫浸染的最适宜温度,寄主死亡率最高,死亡速度也最快。一头5龄和7龄木蠹蛾幼虫能繁殖侵染期线虫16万和48万头。在10℃低温中,线虫不能侵染寄主,但并不死亡,当移入适宜的温度后,能迅速恢复活动。在35℃高温中,线虫则很快死亡。
Results of the laboratory studies conducted during 1986-1988 in Beijing showed that 5 strains (Agriotos, All, Mexican, NC 116 and Florida) of Steinernema feltiae had high infectivities to the larvae of carpenter worm, H. insular is, but not to its pupae. In an experiment with the strain Agriotos, the host mortality and the killing speed of the nematode were affected by temperature and the dosages applied. A 92% host mortality was obtained with dosages of over 25 juvenile fhfectives per larva. Wo significant difference was found between mortalities of the 4th-5th instar and 7th-9th instar larvae when treated with the same dosage. The suitable temperature for parasitism and host-killing by the nematode ranged from 15-30℃, but the parasite could not multiply in the host cadaver under the temperatures above 30℃. The optimum temperature,for infection was 25℃, with the highest host mortality and quickest killing. An average of 160,000 and 480,000 infective nematodes could be obtained from each 5th and 7th instar host larva, respectively. The nematode remained inactive when being placed under 10℃, and resumed its activity soon after being transferred to the suitable temperatures. Placing the parasites under 35℃ resulted in quick death with high mortality.
关键词
芜菁夜蛾线虫
线虫
小木蠹蛾
侵染
Steinernema feltiae Holcocerus insulanis entomopathogenic nematode
