三化螟种群动态、大发生原因及防治对策

报道了江淮南部水稻螟虫演变规律 ,总结了近年来三化螟的发生新特点 ,即发生期提早、主害代提前、发生盛期拉长、主害代数增加、峰次明显增多以及田间虫量超历史水平。分析其回升及暴发原因 ,主要有耕作制度变更、品种与茬口布局变化、栽培方式多样化、暖冬以及天敌寄生率下降。提出了防治对策包括栽培防治、灌水灭蛹和药剂治螟 ,其中药剂治螟的关键是适期施药、适当增加防治次数、合理选用农药和改进施药技术。

The population dynamics of the yellow rice borer causes of outbreaks and control strategy

This paper describes the population dynamics in species dominance among the rice borers Tryporyza incertulas (Walker),Chilo suppressalis (Walker) and Sesamia inferens (Walker) in the southern area between the Yangtze and Huaihe Rivers in Anhui Province. The current pest status of the yellow rice borer, T. incertulas in this area is characterized by earlier occurrence and damaging generations, longer damage duration, more damaging generations and population peaks, and a new record population density with the highest number of egg masses being 165 300 per hectare found in July 2000. The possible causes of population rebounds and outbreaks are related to profound changes in cropping systems and cultivation practices, warmer winters and a decrease in parasitoids. A control strategy is presented emphasizing cultural and chemical methods. For a better chemical control authors recommend that treatments are applied at the appropriate time, that the number of applications is increased when necessary, that the right insecticide is used and that application methods are improved.