The Occurrence Characteristics Of Rice Stem Borer And Analysis Of Rice Stem Borer Difference On Rice Varieties With Different Growth Duration In Zhongjiang County

Rice stem borer is a very important insect pest of rice. Due to climate and farming system changes, many new characteristics of rice stem borer has been occurred. In this study, according to the the rice stem borer wintering characteristics, eclosion progress, recent survey of field and rice stem borer difference on rice varieties with different growth duration, we discussed the occurrence characteristics of rice stem borer and analyzed the reason of occurrence characteristics in Zhongjiang county, Deyang city, Sichuan province. The research results on rice stem borer forecasting and prevention has important theoretical and guiding significance.1. Before 2005, the composition of community of the overwintering rice stem borer in Zhongjiang County was mainly composed by Chilo suppressalis (Walker). In 2006, the community of the overwintering borer's composition had been changed. From 2006 to 2013, the community was mainly contributed by Tryporyza incertulas (Walker) which counted for more than 50% at each year, then followed by Chilo suppressalis (Walker), and Sesamia inferens (Walker) just accounted for very a few. Meanwhile, in recent years, since the rice area which harvested by machines increased year by year, the difference of percentage between Tryporyza incertulas (Walker) and Chilo suppressalis (Walker) became smaller and smaller. From 2009 to 2013, the total quantity of overwintering rice stem borer decreased, because the county adapted to plouph field for planting and the area of returning-straws-to-field decreased.2. Except 2007, the composition of first-generation larvae community was mainly composed by Chilo suppressalis (Walker), then followed by Tryporyza incertulas (Walker), and Sesamia inferens (Walker) just accounted for very a few. Furthermore, from 2008 the composition of first-generation larvae community was opposite change with the composition of community of the overwintering rice stem borer. The main reasons for the formation of this feature was Zhongiiang County got into the rain season at the late of May. Therefore, the quantity of Chilo suppressalis (Walker) larvae increased.3. There is no direct correlation between the dynamics of rice stem borer population in Zhongjiang County and three major environmental factors, temperature, relative humidity, rainfall from 2007 to 2013. However, many environmental factors and rice growth related factors may affect the dynamics of rice stem borer population together.4. Based on the investigation of rice stem borer difference on rice varieties with different growth duration, the results showed rice varieties with a short growth duration were got higher severity of rice stem borer damage. Due to their initial heading stage coincided with Tryporyza incertulas (Walker) eggs hatch peak, it was more easy for larve to harm the rice.5. The efficiency of different insecticides to control the striped stem borer, Chilo suppressalis (Walker), were characterized and the results showed that the most effective pesticide to control the striped stem borer were medium and high dosesof 30% Methoxyfenozide · Chlorofluorocarbons insect hydrazone suspension concentrate 30?40 g/667 m2.At break heading stage,che control efficiency was 84.81%?90.86%. At the peak of young larvae,the control efficiency was 83.63%?94.42%.