三化螟发生期复杂化原因分析及测报方法改进意见

近年来，三化螟发生期出现了主害代(三代)的发生期超常规拉长、峰次增多及发生期的阶段性模糊等新特点。分析原因，一是水稻栽培系统变迁，全程生育阶段模糊，使其种群发育不均衡性加大；二是杂交稻大面积推广和虫伤株率提高，降低了三化螟种群发育的整齐性；三是冬季气温对不同龄期越冬幼虫成活率的影响不同，影响到冬后各代的发生期和峰次。据此提出了测报方法的改进意见。

ANALYSIS OF THE COMPLEXITY OF THE YELLOW RICE BORER OCCURRENCE AND IMPROVEMENT OF THE FORECAST METHOD

In recent years, the occurrence of yellow rice borer in the main damaging generation appears super elongation, the increment of the number of the main damage and the fuzzy stage of the occurrence period. The reasons can be contributed to the following. The change of rice cultivation system and fussy growing stage enable the population to grow in different stage. Extension of the hybrid rice and the increase of the incidence of damaged rice plants by yellow rice borer reduce the consistence of the population's growth. The different effect of temperature in winter on the survival of the overwinter larva in different stages affects the occurrence and the number of occurrence of yellow rice borer overwinter. Based on the analysis , the improvement of the forecast method was put forward.