Selection and improvement of insect pathogenic fungi for the control of multi-resistant aphids (PhD)

Aphids, in particular Myzus persicae the peach-potato aphid, have evolved widespread resistance to chemical insecticides and future control is threatened by the arrival of multi-resistant clones from the European continent.  There is therefore a need to develop novel control strategies for aphid management.  While microbial biocontrol agents are widely used in other pests, the generalist pathogenic fungi available for aphid management only have moderate killing power. Moreover, the role these fungi could play in pest management programs designed to slow the spread of resistance is largely unexplored

In this project the student will used a sequenced and well-characterized bank of aphid clones to test whether resistance to chemicals impose a fitness cost in terms of increased susceptibility to fungal infection.  Secondly we will run artificial selection experiments aimed at improving the biocontrol characteristics of pathogenic fungi. Recent work has shown that we can achieve order of magnitude gains in pathogen virulence by using novel selection techniques based on concepts in social evolution.  In this project we will use these novel methods to select for pathogens that are more effective at killing Myzus persicae and tailor the pathogenic trait under selection (speed of kill or transmission) to distinct biocontrol strategies.  We aim to produce clones that have increased killing power in multi-resistant clones, or in M. persicae generally and predict that fungi that are specialized on aphids will have reduced impacts on beneficial insects.   We will therefore test the effects of selection on biocontrol efficacy as well as pathogen specificity.