芜菁夜蛾线虫与玉米螟接触时间对寄主死亡率及死亡速度的关系

在试验室条件下,研究了芜菁夜蛾线虫北京品系与亚洲玉米螟幼虫接触时间,对玉米螟死亡率和死亡速度的影响。结果表明,线虫与玉米螟接触时间在0.5、1、2小时内,玉米螟死亡率随时间的延长而增加,分别为35.3、50.7和61％。4小时以上各处理玉米螟死亡率均达92％以上,差异不明显。线虫与玉米螟接触0.5、8和12小时,其寄主体内进入的线虫数分别为1.2、7.9和23.8～28.3条/虫。玉米螟幼虫的死亡速度也随进人体内线虫数增多而加快,进入一条线虫的寄主在48～96小时内死亡,2～5条线虫的72小时内死亡,6～30条的48小时死亡,31条以上的24小时内死亡。

RELATIONSHIP BETWEEN HOST EXPOSURE TIME OF STEINERNEMA FELTIAE [NEMATODA:STEINERNEMATIDAE] AND THE MORTALITY AND KILLING SPEED OF OSTRINIA FURNACALIS [LEP.:PYRALIDAE]

In laboratory studies conducted during 1990-1991 in Beijing, artificially mass reared eniomopathogenic nematode, Steiaernema feltiae Beijing strain was placed in contact with 3rd instar Gstrinia furnacalis larvae for 0.5,1,2, 4,8,12,18 arid 20 hr, respectively. The results showed that the larval mortality of O. furnacalis increased as the length of exposure time to the nematode prolonged in the order of 0,5, 1 and 2 hr. The mortality was 35.3%, 50.7% and 61%, respectively. When the exposure time was 4 hr or longer, the larval -mortalities were above 92% without significant difference among treatments. The number of nematode penetrated into the host increased as the exposure time extended. When the exposure time was 0.5, 8 and 12 hr and longer, an average of 1.2, 7.9 and 23.8-28.3 nematodes were found respectively in one host larva. The infected larvae were killed in 48-96 hr, 72 hr, 48 hr and within 24 hr, when a larva was infected by 1, 2-5, 6-30 and over 31 nematodes, respectively.