Improving biological control in UK organic vegetable growers

改善英国有机蔬菜种植者的生物控制

• 批准号: 1712203
• 金额: --
• 依托单位: Harper Adams University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1712203
• 关键词: Improving; biological; control; UK; organic

Glasshouse herbs and vegetables are high value crops within the UK. Production of these crops has increased greatly over the last twenty years and a number of producers are organic or contemplating the switch to organic production. Currently, pest control in non-organic producers is heavily reliant on conventional chemical pesticides. Due to recent EU safety regulations many of these are being withdrawn. A new EU policy (the Sustainable Use Directive on pesticides, 2009/128/EC) is to promote environmentally friendly, biologically based pest control methods. This change in the policy environment, combined with recent scientific and technological advances, creates real opportunities for biologically-based control agents. The development of new biological control agents has, however, been hampered by a risk-averse, oldfashioned approach based on the system in which conventional chemical pesticides were commercialized. There is now an opportunity to approach the problem with a fresh mind-set and to evaluate current methods and to improve or replace them with novel biological agents.In this project we will focus on biological control within two important crops, herbs, such as parsley, and organic peppers. Parsley is commonly attacked by two aphid species, Cavariella aegopodii and the hawthorn-parsley aphid, Dysaphis apiifolia. In organic peppers the major problem is the leafhopper Empoasca decipiens. The aphid species are commonly treated with commercially available parasitic wasps (parasitoids), originally as single species but more recently in mixtures of sometimes as many as six different species. Despite this, control is commonly less than adequate and growers reportunacceptable losses. On the other hand, in Petri dish and laboratory trials the parasitoids appear to be very effective.In organic pepper cultivation the biological agent recommended against leafhoppers is the egg parasitoid Anagrus atomus. To further complicate matters, peppers are also attacked by aphids, in particular the peach-potato aphid, Myzus persicae and the glasshouse potato aphid, Aulacorthum solani. These are usually successfully controlled using commercially available parasitoids. Unfortunately, control of the leafhopper using A. atomus, is often unsuccessful and growers must then use chemical pesticides to save their crop, thus losing the organic premium and disrupting the successful aphid biological control agents. The use of banker crops, i.e. a non-commercial plant hosting populations of another pest insect on which A. atomus can feed and develop and build up to high enough numbers to keep the leafhopper populations at low levels on the crop, has been suggested, but with mixed success only.This PhD will investigate the factors affecting successfully biological control of the pests of parsley and peppers. It is for example, hypothesized that the spacing in commercial parsley production is making it difficult for the parasitoids to locate their aphid hosts and that in addition, the extremely fast production schedule, 3-4 weeks from germination to harvest in parsley, whilst long enough to allow aphid populations to reach damaging levels is insufficient to allow parasitoids to act effectively. We will thus test the effects of planting density and spacing on the growth and development of aphid populations and parasitoid searching efficiency. In addition we will investigate the effect of earlier parasitoid release. In the peppers it is possible that A. atomus is finding host location difficult as the peppers are possibly not activating their defence systems (these are known to attract natural enemies) early enough in response to leafhopper egg laying or that the bankerplants are not correctly placed or of sufficient quality. We will test if applying cis-jasmonate will stimulate the plant defence system and result in improved biological control. The placement and species of banker plants will also be investigated.

温室草本植物和蔬菜是英国的高价值作物。这些作物的生产在过去二十年中大大增加，许多生产者是有机的或考虑转向有机生产。目前，非有机生产者的虫害防治严重依赖于传统的化学农药。由于最近的欧盟安全法规，其中许多正在撤回。欧盟的一项新政策（农药可持续使用指令，2009/128/EC）是促进环境友好型生物虫害控制方法。政策环境的这种变化，加上最近的科学和技术进步，为基于生物的控制剂创造了真实的机会。然而，新的生物控制剂的开发受到了基于常规化学农药商业化体系的规避风险的老式方法的阻碍。现在有一个机会，以一种新的思维方式来处理这个问题，并评估目前的方法，并改进或取代他们与新的生物制剂。在这个项目中，我们将集中在两个重要的作物，草药，如欧芹，和有机辣椒的生物控制。欧芹通常受到两种蚜虫的攻击，Cavariella aegopodii和山楂-欧芹蚜虫Dysaphis apiifolia。在有机辣椒中，主要的问题是小绿叶蝉。蚜虫物种通常用商业上可获得的寄生蜂（寄生蜂）处理，最初是单一物种，但最近有时多达六种不同物种的混合物。尽管如此，控制通常是不够的，种植者恢复可接受的损失。另一方面，在培养皿和实验室试验中，寄生蜂似乎非常有效。在有机辣椒栽培中，推荐的防治叶蝉的生物制剂是卵寄生蜂Anagrus atomus。使问题更加复杂的是，辣椒也受到蚜虫的攻击，特别是桃-马铃薯蚜虫，桃蚜和温室马铃薯蚜虫，茄病条壳蚜。这些通常是成功地控制使用商业上可用的寄生虫。不幸的是，使用A.因此，种植者必须使用化学杀虫剂来拯救他们的作物，从而失去了有机溢价并破坏了成功的蚜虫生物控制剂。利用庄家作物，即一种非商业性的植物，寄主另一种害虫种群，A. atomus可以喂养和发展，并建立了足够高的数量，以保持在作物上的低水平的叶蝉种群，已被建议，但只有混合successful.This博士将调查成功的影响因素生物防治的荷兰芹和辣椒害虫。例如，假设商业欧芹生产中的间隔使得拟寄生物难以定位其蚜虫宿主，并且另外，极快的生产时间表（从欧芹发芽到收获的3-4周）虽然足够长以允许蚜虫种群达到破坏性水平，但不足以允许拟寄生物有效地起作用。因此，我们将测试种植密度和间距对蚜虫种群生长发育和寄生蜂搜索效率的影响。此外，我们将调查的影响，较早的寄生释放。在辣椒中，A. atomus发现很难找到寄主，因为辣椒可能没有足够早地激活它们的防御系统（已知这些系统会吸引天敌）来应对叶蝉产卵，或者没有正确地放置bankerplants或质量不够。我们将测试施用顺式茉莉酸酯是否会刺激植物防御系统并导致生物防治的改善。还将调查河岸植物的位置和种类。