蝗虫微孢子虫处理剂量与海南省荒地东亚飞蝗感病率的相互关系

Relationships Between Application Rate of Nosema locustae and Infection of Locusta migratoria manilensis in Hainan Province

在海南省儋州市的东亚飞蝗 ( L ocusta migratoria manilensis)发生区 ,采用蝗虫微孢子虫 ( N osemalocustae)分别以 4 9.5× 10 9孢子 .hm-2 (小区 1)、99× 10 9孢子 .hm-2 (小区 2 )和 150× 10 9孢子 .hm-2 (小区 3)剂量处理 ,处理时间为 1999- 0 7- 10— 0 7- 2 2。自处理后第 3周开始 ,上述 3个处理区中的飞蝗虫口密度均显著下降 ,极显著低于处理的对照区 ,处理区中的平均虫口密度均在处理指标以下。特别是在处理后第 10周时 ,不处理对照区中的平均飞蝗虫口密度高达 7.74头 .m-2 ,远高于其他 3个处理区中的虫口密度 ,分别为 0 .12头 .m-2、0 .18头 .m-2和 0 .0 6头 .m-2。处理后微孢子虫处理 3个小区中残存活飞蝗的感病率在调查期间 (处理后第2周至第 10周 )均呈上升趋势 ,到第 10周高达 35.7%～ 4 0 .6%。以 99× 10 9孢子 .hm-2和 150× 10 9孢子 .hm-2剂量处理的小区 ,成虫个体在整个种群中所占比例均为 0 ,而不处理的对照区的成虫比例达 14.5% ,以 4 9.5×10 9孢子 .hm-2剂量处理的成虫比例为 4 0 % ,但是在 50个样方中仅成虫总头数为 4头 ,而对照区为

The large scale trials for determining the relationships between the dosage of N. locustae and infection of locusts in sugarcane grassland ecosystem, Hainan province were conducted, from 10th, July to 22nd, September, 1999. In the region, Oriental migratory locust ( Locusta migratoria manilensis ) has 4 generations per year. The mean densities of locusts in plots treated with N. locustae spores at application rates of 49.5×10 9 spores·hm -2 (plot 1), 99×10 9 spores·hm -2 (plot 2), and 150×10 9 spores·hm -2 (plot 3), were significantly reduced contrast with before treatment. Whereas in plot 4 as a control (untreated), the densities increased from 0.62 individuals·m -2 to 7.70 individuals·m -2 in 9 weeks during the time. The infections of locusts by N. locustae increased early with increase of dosage of N. locustae , however decreased in the next generation and next year. The dosage of N. locustae has no effect on the distributions of infection in development stages of locusts.