Effects of adding wheat stalks and depth of ploughing on numbers of rice planthoppers and spider communities in rice fields
Author of the article:WAN Nian-Feng** JI Xiang-Yun ZHANG Yong-Xing JIANG Jie-Xian***
Author's Workplace：Ecological Environment Protection Research Institute, Shanghai Academy of Agriculture Sciences, Shanghai 201403, China
Key Words：returning wheat stalk into rice field, rice planthopper, spider, plough
Abstract：[Objectives] To determine the effects of adding wheat stalks and depth of ploughing on numbers of rice planthoppers and spiders in rice fields. [Methods] We compared the effect of three treatments; “deep ploughing (20 cm) + wheat stalks”, “shallow ploughing (10 cm) + wheat stalks”, “deep ploughing (20 cm)” plus a control; “shallow ploughing (10 cm)”, on numbers of rice planthopper adults and nymphs as well as the number of spiders. [Results] Within the investigation period (July to October), the numbers of rice planthoppers per 100 rice plants in each of the above three treatments were (17.7±3.5), (18.1±3.7) and (21.0±4.0), respectively, which were 25.6%, 23.95% and 11.76% less than the control, respectively. Adding wheat stalks and depth of ploughing had no significant effect on the number of spiders or the control of rice planthoppers by spiders, but the number of spiders and the ratio of the number of spiders to rice hoppers were both significantly higher in the treatments in which wheat stalks were added to rice fields than in those in which they were not. [Conclusion] Returning wheat stalks to rice fields can significantly enhance the biological control of planthoppers by spiders in rice fields.