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稻纵卷叶螟是水稻常见害虫之一,在菲律宾包括3个种,即Cnaphalocrocis medinalis、Maras-mia patnalis和M.exigua。根据1989年雨季在吕宋岛两个不同地区的调查,共记载了15个初寄生和2个重寄生性天敌,其优势种主要寄生2或3龄幼虫,杀死寄主在5龄之前。用值k和Bellows(1981)的密度制约模型分析表明,幼虫寄生作用是稻纵卷叶螟田间种群的一个直接密度制约死亡因子,这种作用属补偿不足(b<1),并具有时滞效果。讨论指出,在调查时应避免使用某一时刻寄生率,来评价寄生性天敌的作用,而需要综合考虑寄主密度及随时间而变化的条件。
Rice leaf roller is one of the common pests in rice, including 3 species in the Philippines, namely Cnaphalocrocis medinalis, Maras-mia patnalis and M.exigua. According to the survey conducted in two different areas of Luzon Island during the rainy season of 1989, a total of 15 primary parasites and 2 parasitoid natural enemies were recorded. The predominant parasites mainly parasitized 2nd or 3rd instar larvae, killing the host before 5th instar. The density-constrained model analysis using the values k and Bellows (1981) showed that larval parasitism is a direct density-dependent death factor in the rice field and is compensated (b <1) with lag effect. The discussion pointed out that the survey should avoid the use of parasites at a certain moment to evaluate the role of parasitic natural enemies, and the need to consider host density and time-varying conditions.