Effect of Six-fourth Generation Cnaphalocrocis medinalis (Guenée) on Rice yield and Control Index

[Objective] The study aimed to find out effects of six-fourth generation Cnaphalocrocis medinalis （Guenée） on rice production in Yangzhou district and its control index. [Method] Through artificial control of insects in field, four different insect volume gradients were set, the effects of different C. medinalis amounts on leaf roll rate and yield loss of Wuyunjing No.23 were determined. [Result] The results showed that within the range of 0-20 head/hill, as the amounts of insect increased, rice yield decreased, leaf roll rate and rice yield loss rate increased. According to 3% economic permit loss rate, the control index of C. medinalis on Wuyunjing No.23 was 173 head/hill. [Conclusion] The study would provide theoretical basis for effective controlling of six-fourth generation C. medinalis in Yangzhou district.

Main Rice Pests Control with Trichogramma japonicum

This study used Trichogramma japonicumto to control Chilo suppressalis （Walker） and Cnaphalocrocis medinalis（Guenée）, and tested the effects of different control methods on main rice pests, natural enemies and rice yield. The results revealed that the parasitism of Trichogramma japonicum in the eggs of Chilo suppressalis （Walker） and Cnaphalocrocis medinalis （Guenée） reached 60.3% and 57.1%, and the control efficacy was up to 70.8 % and 91.99%, respectively. The control efficacy for Cnaphalocrocis medinalis （Guenée） was much better. This biological control method could be equivalent to chemical control method in the control effects on main pests in rice. The yield under the biological control was 26.5% higher than that of the control group, and the biological control had a signifcant increase in the number of natural enemies such as spider, up to 400 per 100 plants. Therefore, the sustainable prevention and control were achieved in the presentence with natural enemy organism.

稻纵卷叶螟发生的气象条件等级预报

通过对桂林地区近5a水稻稻纵卷叶螟发生资料与气象资料进行对比分析,选择影响桂林地区稻纵卷叶螟发生的气象因子（温度、降水、风向、风速、湿度）,考虑前期气象条件和虫源数,采用回归分析方法,建立水稻稻纵卷叶螟迁飞的气象条件等级预报模型。模型中的预报对象为气象条件综合等级,分长期和短期预报,将各预报对象和预报因子划分为5级,用当地气象台发布的月、季度及一周天气预报结论,综合分析前期虫源数是否有利,对未来月、季和1~7d逐日影响稻纵卷叶螟迁飞的气象条件等级进行预报。预报业务系统实用性强,逐日预报准确率达到了70%以上,在生产实践中发挥了积极的作用。

30%茚虫威悬浮剂防治水稻稻纵卷叶螟的效果

应用30%茚虫威悬浮剂防治水稻稻纵卷叶螟(Cnaphalocrocis medinalis Guene)。试验结果表明,该药剂对稻纵卷叶螟具有良好的防治效果,施药量在18、27、36 g(ai)/hm2浓度时,药后18 d防治效果分别为82.08%、84.28%、87.68%,且持效期较长。试验期间未发现该药剂在供试剂量下对水稻产生药害,从使用成本与防治效果两方面综合考虑,生产上30%茚虫威悬浮剂的使用剂量以27～36 g(ai)/hm2为宜。

虫酰·辛硫磷20%乳油防治稻纵卷叶螟和稻飞虱初步试验

试验结果表明:在稻纵卷叶螟的卵孵始盛期和稻飞虱的若虫盛期,用虫酰·辛硫磷20%乳油100g/667m2,药后15d对稻纵卷叶螟与稻飞虱的防治效果均达到95%以上。对稻纵卷叶螟的防治效果显著优于稻丰散50%乳油120g/667m2,对稻飞虱的防治效果与吡蚜酮25%可湿性粉剂25g/667m2之间无显著差异。

稻纵卷叶螟防治药剂配方筛选

为减少高毒、高残留农药的使用,提高水稻纵卷叶螟的防治效果,对不同配方的药剂进行了田间试验。结果表明:T3处理防治效果最好,分别比T1处理和T2处理药后3 d防效高16.65%,5.89%,药后7 d防效高6.74%,1.12%,药后10 d保叶效果高3.97%,1.66%;T5处理的省水效果最好,药后3,7 d的防治效果分别是72.55%,78.65%,比T4处理药后7 d防效高2.25%,药后10 d保叶效果是82.45%,比T4处理高1.66%。

50%虎蛙等几种杀虫剂对稻纵卷叶螟的防治效果

田间试验示范结果表明:虎蛙EC对稻纵卷叶螟有良好的防治效果。2龄幼虫高峰期用80ml/667m2,药后3、7d杀虫效果分别为90.2%和94.1%,保叶效果分别为82.0%和87.7%,优于30%螟服EC70ml/667m2和40%三唑磷EC80ml/667m2。3龄幼虫高峰期用100ml/667m2,药后4、6d杀虫效果仍达80.1%以上。

垄歌防治水稻二化螟及稻纵卷叶螟幼虫的效果研究

二化螟和稻纵卷叶螟是我国南方水稻上最主要的害虫。研究了20%氟苯虫酰胺(垄歌)等药剂对二化螟和稻纵卷叶螟的田间防效,结果表明使用20%氟苯虫酰胺水分散粒剂150 g/hm2,药后3 d的防效分别为86.3%、92.2%,药后14 d的保苗(叶)效果分别为83.1%、93.8%,均略高于康宽和稻腾常规推荐剂量的防效。