Using landscape genomics to improve management of insect pest species

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Insect pests have a widespread negative impact in agriculture, resulting in very large economic loses. Monitoring and surveillance of pest species is fundamental to control their populations and reduce the damage they inflict on crops. This is because an early detection improves the chances of controlling them before they spread out and increase their population size. However, studying the migration of small insects can be problematic due to the difficulty of tracking individuals. In addition, resistance to pest control methods, whether to insecticide or to host-plant resistant cultivars, is becoming an increasingly important issue. Inferring the population structure of pest species and the connectivity across populations and landscapes is key to understand migration patterns, which can be used to inform pest surveillance and control schemes. This fully-funded project provides an exciting opportunity to apply population genomics and evolutionary concepts to improve insect pest management and understand the evolution of resistance.The project will use Nasonovia ribisnigri, the currant-lettuce aphid, as a model system to evaluate how landscape genomics can be used to improve aphid surveillance and control the spread of resistance alleles. The currant-lettuce aphid, Nasonovia ribisnigri, is a major pest of lettuce crops responsible for large economic losses. One of the most efficient way to reduce aphid infestations and damage is growing host-resistant lettuce cultivars that stop aphids from colonising the plant. However, the capacity of breaking the host-plant resistance mechanism (Rb) has recently evolved in some biotypes. In these circumstances, surveillance and monitoring of crops becomes of great importance to produce early warning information that would improve targeted control of N. ribisnigri before aphids enter the lettuce head. However, the paradox is that whilst winged aphids are quick to colonise the lettuce crop in spring they are unusually scarce in both water traps and suction traps. Understanding the migration patterns of the species is, therefore, fundamental to design efficient methods of capture and control. For this, the project will use genomics to infer the population structure and the levels of gene flow between populations of N. ribisnigri at different geographic scales and different landscapes. This knowledge will be used to develop surveillance methods that maximise the observation of individuals of the species at the early stages of their migration into the crops. Furthermore, these results combined with the development of genome-wide markers for the Rb phenotype will provide fundamental information about the evolution and spread of resistance across the UK.You will be based at Rothamsted Research working within the Insect Survey group, a national capability dedicated to the monitoring of aphid and moth populations in the UK. You will be registered at the University of Warwick and field work will be carried out closely with the UK's leading lettuce producer G's. Thus, the studentship offers extensive opportunities to engage with one of Europe's leading family-owned fresh produce companies, growing and supplying a vast array of fresh, high quality crops to all the major UK retailer and many European retailers.