Multiple stressor effects on biological pest control; improving efficacy in challenging environments.

对农业生产力和可持续性的竞争需求导致微生物生物农药成为一种不可或缺的作物保护工具。在有管理的温室和具有可变环境条件的开放式农艺系统中，在真正的综合病虫害管理规划中发展微生物控制，提出了科学挑战。为了确保未来安全有效地使用，需要对微生物与农药组合之间发生的基本相互作用有更好的科学认识。这包括在复杂的生物和非生物环境中，相互作用对微生物对目标生物的功效的影响，以及对其他应激源的敏感性是否在非目标生物中受到影响。最近的研究已经研究了从生态毒理学到无脊椎动物病理学的混合毒性模型的转换，该项目将通过利用新的实验设计和数据分析，进一步提高我们描述病原体如何相互作用的能力。目的是检测和了解害虫抑制方面的协同作用、拮抗作用或可加性，通过与其他化学投入物的组合设计来控制杂草、害虫和疾病，提高微生物害虫控制的可靠性和弹性，以最大限度地提高效果。学生将研究共同感染的微生物昆虫病原体和其他毒物之间的基础生态相互作用如何影响疾病的严重程度，病原体适应性以及对害虫控制潜力的影响。这将为在实际应用中提高生物防治效果提供目前缺乏的关键认识。该项目的总体目标是：1)确定病原体/化学效应在何处以及如何最有效地结合；2)了解多种应激源在不同环境下如何影响组合效应。实现这些目标的“试验台”是一个示范作物（西红柿）和害虫（粉虱/蓟马）系统，用于一系列日益复杂的实验。Yr1的工作将是高度控制的微观实验，允许精确的操作，重要的数据生成和早期同行评审的出版物。在Yr2中，中观和初步田间试验将检验Yr1结果的预测。扩展到Y2/3，现场试验（由CASE合作伙伴大力支持的温室工作）和额外的实验将在更复杂的系统中验证预测。多个温室设施将允许学生进行连续的实地试验，从而降低交付风险。学生将解决的具体问题有：1. 二元病原体/化学混合物影响协同作用发生的可能性的关键方面是什么？剂量、应变和应用时间等因素如何改变结果？在宿主死亡率、适应性成本和宿主群体的二次循环能力方面，混合相互作用中病原体之间的权衡是什么？环境生物/非生物应激源如何影响微生物对生态系统中目标宿主和非目标自然发生的调节病原体的影响？从生态毒理学到无脊椎动物病理学的创新方法，加上CASE和项目合作伙伴在全球应用生物防治方面的专业知识，将在无脊椎动物病理学、生态毒理学、寄生虫学、分子技术、建模和生态学方面带来卓越水平的培训和研究前景。

Competing demands for agricultural productivity and sustainability have led to microbial biopesticides emerging as an integral crop protection tool. Developing microbial control in truly integrated pest management programmes, both in managed glasshouse and open agronomic systems with variable environmental conditions, presents scientific challenges. A better scientific understanding of fundamental interactions occurring between microbes and pesticides in combination is needed to ensure safe and effective future use. This includes the impact of interactions on microbial efficacy towards target organisms and whether sensitivities to other stressors are affected in non-target organisms, all within complex biotic and abiotic environments.Recent studies have investigated translation of mixture toxicity models from ecotoxicology to invertebrate pathology and this project will further our ability to describe how pathogens interact, by utilising novel experimental designs and data analysis. The aim is to detect and understand synergism, antagonism or additivity in terms of pest suppression, to improve reliability and resilience of microbial pest control through combination designs with other chemical inputs for control of weeds, pests and disease to maximise effects. The student will investigate how underpinning ecological interactions between co-infecting microbial insect pathogens and other toxicants affect the severity of disease, pathogen fitness and the impact on potential for control of pest insects. This will provide key understanding currently lacking for improving the efficacy of biological control in an applied situation. The overarching aims of the project are to; i) identify where, and how, pathogen/chemical effects combine most effectively and ii) understand how multiple stressors will impact on combination effects under variable environments. The "test bed" for these aims is an exemplar crop (tomatoes) and pest (whitefly/thrips) system for a series of experiments of increasing complexity. Work in Yr1 will be highly controlled microcosm experiments, allowing accurate manipulation, significant data generation and early peer reviewed publication. In Yr2, mesocosm and initial field trials will test predictions from Yr1 results. Expanding to Y2/3, field trials (glasshouse work significantly supported by the CASE partner) and additional experiments will validate predictions in more complex systems. Multiple glasshouse facilities will allow the student to undertake sequential field trials, thus reducing delivery risk. Specific questions the student will address are; 1. What are key aspects of binary pathogen/chemical mixtures that influence the likelihood of synergism occurring? How are outcomes altered by factors such as dose, strain and timing of application?2. What are the trade-offs in communities between pathogens in mixed interactions in terms of host mortality, fitness costs and ability to secondary cycle in the host population?3. How do environmental biotic/ abiotic stressors affect microbial impacts on target hosts and non-target naturally occurring regulating pathogens in the ecosystem? The innovative link of approaches from ecotoxicology to invertebrate pathology, coupled with expertise of the CASE and project partner in applied biological control worldwide will bring an exceptional level of training and research prospects in: invertebrate pathology, ecotoxicology, parasitology, molecular techniques, modelling and ecology.