An Environmental Model for Developing Novel IPM Techniques for Control of Swede Midge in Brassicas

2020年，英国种植了27,420公顷园艺甘蓝，对英国经济的价值为3.02亿GB(Defra园艺统计，2020)。近年来，由于杀虫剂毒死蜱的丧失，瑞典姬蜂已经成为英国油菜生产的毁灭性威胁。幼虫取食对花椰菜、西兰花和卷心菜等结球作物尤其构成威胁。由于蚊子的存在，这些作物中的一些不可能再有机种植了。使用作物网罩可以通过排除成虫来减少瑞典蚊的危害，从而防止产卵，但需要进行研究，以更有效地利用这些网罩并更好地了解作物风险，特别是因为它们经常被移走进行机械除草。目前的建议是依靠轮换和与以前被侵染的作物的距离来防止第一代成虫从土壤中越冬的幼虫和蛹中出来时被殖民。然而，在距离最近的甘蓝作物20英里的田里发现了虫害，这些作物以前已经有7-8年没有种植甘蓝了。这种行为使开发新的防治策略变得困难，值得研究。本项目建议利用地理信息系统开发一个环境模型，以了解景观和作物历史因素如何影响第一代和第二代瑞典姬蜂的害虫压力。该环境模型将对传统和有机甘蓝种植者同样有用，以帮助为作物保护决策和规划提供信息。该项目还将使用网状作物覆盖来评估瑞典蚊虫的虫害压力，考虑到作物历史和景观特征，以确定蚊虫是从当前油菜田的土壤中冒出来的，还是从其他来源飞入作物的。该项目的成果将有助于设计有效的新型农业生态控制战略，其基础是关于瑞典蚊生物学和行为的知识，例如诱捕种植或使用抑制覆盖作物。

There were 27,420 ha of horticultural brassicas grown in the UK in 2020, worth £302 million to the UK economy (Defra horticulture statistics, 2020). Swede midge has become a devastating threat to UK brassica production in recent years, since the loss of the insecticide chlorpyrifos. Larval feeding is particularly threatening to headed crops like cauliflower, broccoli and cabbage. It is not possible to grow some of these crops organically anymore because of the midge. Use of crop mesh covers can reduce swede midge damage by excluding the adult midges and thus prevent egg laying but research is needed to use these more effectively and better understand the crop risks, especially as they are often removed for mechanical weeding. Current advice is to rely on rotation and distance from previously infested crops to prevent colonisation of the first-generation midge adults when they emerge from overwintered larvae and pupae in the soil. However, infestations have been found in fields located 20 miles from the nearest brassica crop on land that had not previously grown brassicas for 7-8 years. This behaviour makes it difficult to develop novel control strategies and is worthy of research.This project proposes to develop an environmental model using GIS to understand how landscape and crop history factors influence pest pressure of the first and second generations of swede midge. The environmental model will be useful to conventional and organic brassica growers alike to help inform crop protection decision making and planning. The project will also assess swede midge pest pressure with the use of mesh crop covers, taking into account crop history and landscape features to determine whether the midges are emerging from the soil in the current brassica field or flying into the crop from another source. The results of this project will help to design effective novel agroecological control strategies based on knowledge of swede midge biology and behaviour, such as trap cropping or use of suppressive cover crops.