Biological crop protection: a new 'slow down/speed up' strategy for aphid management

蚜虫是广泛存在的农作物的重要害虫。对于户外种植的农作物，包括大田蔬菜和可耕种植物，管理蚜虫的标准方法一直是使用合成化学杀虫剂。最初这些措施非常有效，但过度使用杀虫剂已导致一些关键的蚜虫进化出抗药性。与此同时，也有人担心农药使用对环境的影响，这导致许多产品被召回销售。比如新烟碱。这使得农民几乎没有可行的选择来控制现在已经成为农业生产的主要威胁的蚜虫害虫。迫切需要一种可供农民使用的可持续的蚜虫管理形式。为了使作物保护更可持续，更不容易产生耐药性，最好不要过度依赖任何一种干预。可以通过综合害虫管理(IPM)实现策略多样化，IPM是一种通过以环境敏感的方式结合不同的互补防治药剂来控制害虫的方法。这些方法主要应该是生物方法，包括培育抗虫害的作物品种，使用寄生蜂等天敌，以及以有益微生物或天然产品为基础的“生物农药”产品。这些作物保护工具对人类和环境都是安全的，因此它们应该提供一种更好的作物保护形式。化学杀虫剂确实在综合防治中发挥作用，但只有在必要时才使用化学杀虫剂，以减少害虫对它们产生抗药性的机会。不幸的是，由于农民一直非常依赖化学杀虫剂作为害虫控制的主要形式，目前还没有针对大田作物中的大多数蚜虫的有效的IPM系统。由于缺乏新的害虫防治剂，以及缺乏关于它们在一起使用时如何相互作用的知识，IPM的发展一直受到阻碍。该项目涉及五项相互关联的工作。(1)利用多种十字花科作物类型的基因表达数据来鉴定对蚜虫表现出高概率抗性的植物品系，这将在实验室用蚜虫取食植物的实验中得到证实。基因表达数据将允许开发出可供种子公司在其植物育种计划中使用的遗传标记。(2)通过一系列室内和田间试验，确定了植物抗蚜性的生物学基础。(3)进行真菌生物农药的研究，以确定它们的药效如何受田间环境条件的影响，以及了解作物植物抗性如何影响其对蚜虫的药效。(4)互补性研究着眼于不同类型的十字花科植物如何影响寄生黄蜂的功能，寄生黄蜂是大田作物上重要的蚜虫自然控制剂。(5)在田间IPM系统中研究了抗病作物、真菌生物农药和寄生蜂之间的相互作用。该项目的目的是开发大田作物蚜虫综合防治系统所需的新知识和新工具。这项工作的重点是桃属土豆蚜虫，它是一种危害多种农作物的害虫，已经对许多常用杀虫剂产生了抗药性。实验涉及蔬菜甘蓝和油菜，但目的是在未来的研究中将该系统扩展到其他作物(甜菜、土豆)。这项研究基于一种假设，即具有部分抗性的油菜植株会减缓蚜虫的发育，从而使害虫更容易受到生防剂的影响，并通过生物杀虫剂和寄生蜂加快防治速度。该项目将使农民和种植者以及供应链上的其他人受益。改善粮食安全和更好地保护环境将使普通公众受益。

Aphids are important insect pests of a wide range of crop plants. For crops grown outdoors, including field vegetables and arable plants, the standard way of managing aphids has been to apply synthetic chemical insecticides. Originally these were very effective, but excessive use of pesticides has caused some key aphid pests to evolve resistance. At the same time, there are concerns about the environmental impact of pesticide use, which has led to many products being withdrawn from sale. Such as the neonicotinoids. This has left farmers with few workable options for controlling aphid pests which have now become a major threat to farm production. A sustainable form of aphid management that can be used by farmers is urgently needed. To make crop protection more sustainable and less prone to resistance, it is better not to over-rely on any one intervention. Diversification of tactics can be achieved through Integrated Pest Management (IPM), a way of controlling pests by combining different, complementary control agents in an environmentally sensitive way. These should principally be biological methods that include breeding pest resistant crop varieties, the use of natural enemies such as parasitic wasps, together with 'biopesticide' products based on beneficial microbes or natural products. These crop protection tools are safe for people and the environment and so they should provide a better form of crop protection. Chemical insecticides do have a role in IPM, but they are used only when necessary in order to reduce the chances of pests evolving resistance to them. Unfortunately, because farmers have been so reliant on chemical insecticides as the principle form of pest control, there is currently no effective IPM system in place yet for the majority of aphid pests in field crops. The development of IPM has been held back by a lack of new pest control agents and the knowledge about how they interact when used together. The project involves five interlinked pieces of work. (1) Data on gene expression from multiple brassica crop types is used to identify plant lines that have a high probability of showing resistance to aphids, and this will be confirmed in experiments with aphids feeding on plants in the laboratory. The gene expression data will allow genetic makers to be developed that can be used by seed companies in their plant breeding programmes. (2) The biological basis for plant resistance to aphids is determined using a series of laboratory and field experiments. (3) Research on fungal biopesticides is done to determine how their performance is affected by the environmental conditions in the field, and also to understand how crop plant resistance affects their efficacy against aphids. (4) Complementary research looks at how different types of brassica plant, with resistance to aphids, affect the function of parasitic wasps, which are important natural control agents of aphids on field crops. (5) The interaction of resistant crops, fungal biopesticides and parasitoids are studied in the field in an IPM system. The aim of this project is to develop the new knowledge and tools needed for an IPM system for aphid pests of field crops. The work centres on the peach potato aphid, Myzus persicae, which is a pest of a wide range of crops and has evolved resistance to many commonly used insecticides. The experiments involve vegetable brassicas and oilseed rape but the intention is to extend the system to other crops (sugar beet, potatoes) in future research. The research is based on a hypothesis that brassica plants with partial resistance that slows down aphid development makes the pest more susceptible to biological control agents and speeds up control with biopesticides and parasitic wasps. The project will benefit farmers and growers and others in the supply chain. The general public will benefit from improved food security and better care of the environment.