Institute of Insect Sciences, Zhejiang University, 310058 Hangzhou, Zhejiang, China.
Jiaxing City Jia Xin Cai Agricultural Development Group Co. Ltd., 314000 Jiaxing, Zhejiang, China.
Environ Entomol. 2021 Aug 12;50(4):842-851. doi: 10.1093/ee/nvab027.
Insecticide overuse in crop production systems often results in detrimental effects on predators and parasitoids, which regulate important insect pests. The natural enemies are also unable to survive in monocrop landscapes with the absence of shelter or food sources. Diversified vegetation, especially with flowering plants, can enhance natural enemy abundance and diversity, thus strengthening biological control, enabling farmers to reduce insecticides. In this study, we conserved bund vegetation and manipulated the existing rice landscapes with flowering plants to provide food and shelter for the biological control agents. Our study revealed significant positive relationships between predator densities and bund plant diversity. The abundance of predators significantly increased in the eco-engineered plots, especially at the flowering peaks compared to the insecticide-treated and control plots, while parasitoids were more diverse in both the eco-engineered and control plots. There were no significant differences in planthopper and leafhopper densities among the treatments during the rice early and maximum tillering stages, suggesting effective natural control of these herbivore pests in the eco-engineered plots at the early rice-growing season. However, at the heading stage relatively higher planthopper and leafhopper populations in the control and eco-engineered plots than in the insecticide-sprayed plots were recorded, suggesting perhaps the need for insecticide interventions if exceeding the threshold at this time. Our study indicates that manipulating the habitats surrounding the rice fields to enhance natural enemies is a sustainable practice in rice production as it can enhance the natural suppression of pests and thus reducing the need for insecticide.
在作物生产系统中过度使用杀虫剂通常会对捕食性天敌和寄生性天敌产生不利影响，而这些天敌可以控制重要的虫害。在没有庇护所或食物来源的单一作物景观中，这些天敌也无法生存。多样化的植被，特别是有开花植物的植被，可以增加天敌的数量和多样性，从而加强生物防治，使农民能够减少杀虫剂的使用。在这项研究中，我们保护了田埂植被，并通过种植开花植物来操纵现有的稻田景观，为生物防治剂提供食物和庇护所。我们的研究表明，捕食者的密度与田埂植物多样性之间存在显著的正相关关系。与施药和对照处理相比，在生态工程处理中，捕食者的数量在开花高峰期显著增加，而寄生性天敌在生态工程和对照处理中都更加多样化。在水稻早期和最大分蘖期，处理之间的稻飞虱和叶蝉密度没有显著差异，这表明在早期水稻种植季节，生态工程处理对这些植食性害虫有有效的自然控制。然而，在抽穗期，对照和生态工程处理中的稻飞虱和叶蝉种群数量相对较高，而施药处理中的种群数量较低，这表明如果此时超过阈值，可能需要进行杀虫剂干预。我们的研究表明，通过操纵稻田周围的栖息地来增强天敌是一种可持续的水稻生产实践，因为它可以增强对害虫的自然抑制，从而减少对杀虫剂的需求。
