长江中下游地区杨树主要食叶害虫暴发机制研究及可持续防控技术示范

杨小舟蛾、杨扇舟蛾、分月扇舟蛾、仁扇舟蛾与美国白蛾是我国长江中下游地区(简称“地区”)杨树的主要食叶害虫。自20世纪80年代来，该地区杨树单一种植面积不断扩大，其食叶害虫危害特点、成灾规律也出现新变化，导致生产上出现测不准、控不及、损失大等技术难题。本项目依托国家自然基金、省科技支撑等课题，取得主要研究成果如下。 1.探明该地区食叶害虫分类地位、关键鉴别特征及遗传关系。在分子水平上明确了分月扇舟蛾和仁扇舟蛾是两个独立种。研究了舟蛾选择寄主的行为、生理生化和分子感受机制 明确了舟蛾诱导寄主植物化学防御机理及其对舟蛾的食物选择、生长发育、生理代谢的负反馈机制。掌握了几种害虫在本区域发生规律、治理要素及最适治理期。 2.探明该地区食叶害虫在高温干旱条件下突发、区域性暴发的关键机制。①发现食叶害虫繁殖率在35杨、转基因抗虫杨上比107杨等上低1.4-2.1倍，揭示其抗虫杨区天敌控虫效应成倍增强，而害虫低虫口区增加缓慢。②明确了杨小舟蛾取食不仅诱导提高杨树的直接防御，还通过吸引天敌来增强杨树的间接防御作用及其机理。③在阐释几种害虫发生规律基础上，发现降雨、湿度与舟蛾发生密切相关，持续高温干旱易引起区域性暴发 降雨量、日数增加均不利于害虫种群数量发育，而有利于幼虫病毒病等天敌的发生，显著减轻灾情。 3.揭示食叶害虫抗药性机理。发现了杨小舟蛾等体内重要解毒酶谷胱甘肽S-转移酶（GST）的组织特异性、龄期差异、药剂抑制和亚细胞分布等重要的生化特性，克隆了舟蛾科第一个GST全长基因并对其进行了生物信息学分析，研究了杨小舟蛾GST与植物次生物质的相互关系，明确了昆虫与植物次生物质的互作机制。

Micromelalopha sieversi (Yang's small prominent moth), Clostera anachoreta (Yang's broad-lined prominent moth), Clostera anastomosis (Lobster prominent moth), Clostera restitura (Poplar prominent moth) and Hyphantria cunea (Fall webworm) are the major defoliating pests attacking poplar plantations in the middle and lower reaches of the Yangtze River (hereinafter referred to as "the Region"). Since the 1980s, the monoculture area of poplars in this region has been continuously expanding, and new changes have emerged in the damage characteristics and outbreak patterns of its defoliating pests, leading to technical challenges in production such as inaccurate prediction, delayed control, and severe economic losses. This project, supported by projects including the National Natural Science Foundation of China and provincial science and technology support programs, has achieved the following main research results.
1. Clarified the taxonomic status, key diagnostic characteristics and genetic relationships of defoliating pests in the Region. At the molecular level, it was confirmed that Clostera anastomosis and Clostera restitura are two independent species. The host selection behavior, physiological, biochemical and molecular sensory mechanisms of notodontid moths were studied, and the chemical defense mechanism of host plants induced by notodontid moths and their negative feedback effects on the food selection, growth and development, and physiological metabolism of notodontid moths were clarified. The occurrence patterns, control factors and optimal control periods of several pests in this region were mastered.
2. Clarified the key mechanisms of sudden outbreak and regional outbreak of defoliating pests under high-temperature and drought conditions. ① It was found that the reproduction rate of defoliators on "35" poplars and transgenic insect-resistant poplars was 1.4-2.1 times lower than that on "107" poplars, revealing that the natural enemy-mediated pest control effect in insect-resistant poplar plantations was significantly enhanced, while the pest population in low-density areas increased slowly. ② It was confirmed that the feeding of Micromelalopha sieversi not only induced the enhancement of direct defense of poplars, but also enhanced the indirect defense of poplars by attracting natural enemies and revealed the underlying mechanism. ③ Based on the elucidation of the occurrence patterns of several pests, it was found that rainfall and humidity are closely related to the occurrence of notodontid moths; continuous high-temperature and drought conditions are prone to cause regional outbreaks, while increased rainfall and rainy days are not conducive to the development of pest populations, but beneficial to the occurrence of natural enemies such as larval viruses, significantly reducing disasters.
3. Revealed the insecticide resistance mechanism of defoliating pests. Important biochemical characteristics of glutathione S-transferase (GST), an important detoxifying enzyme in Micromelalopha sieversi and other pests, were discovered, including tissue specificity, instar-specific differences, chemical inhibition and subcellular distribution. The first full-length GST gene of the Notodontidae family was cloned and subjected to bioinformatic analysis. The interaction between GST of Micromelalopha sieversi and plant secondary metabolites was studied, and the interaction mechanism between insects and plant secondary metabolites was clarified.