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

2020年，英国种植了27,420公顷的园艺芸苔，对英国经济的价值为3.02亿英镑（Defra园艺统计，2020）。近年来，由于杀虫剂毒死蜱的消失，瑞典蠓对英国芸苔的生产构成了毁灭性的威胁。幼虫取食对花椰菜、西兰花和卷心菜等抽穗作物的威胁尤其严重。由于蚊子的存在，有些农作物不可能再有机种植了。使用作物网罩可以通过排除成蚊来减少蠓的危害，从而防止产卵，但需要进行研究，以更有效地使用这些蚊帐，并更好地了解作物风险，特别是因为它们经常被机械除草。目前的建议是依靠轮作和远离以前被侵染的作物来防止第一代蠓成虫在土壤中越冬的幼虫和蛹中出现时的殖民化。然而，在距离最近的芸苔作物20英里的土地上发现了侵染，这些土地以前没有种植芸苔7-8年。这种行为使得开发新的控制策略变得困难，值得研究。本项目拟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蠓的害虫压力。环境模型对传统和有机芸苔种植者都很有用，有助于为作物保护决策和规划提供信息。该项目还将利用网状作物覆盖评估瑞典蠓的虫害压力，同时考虑到作物历史和景观特征，以确定蠓是来自当前芸苔田的土壤还是从其他来源飞入作物。该项目的研究结果将有助于设计有效的新型农业生态控制策略，这些策略基于对瑞典蠓生物学和行为的了解，如诱捕种植或使用抑制性覆盖作物。

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.