Improving biological control of slugs and investigating the factors that influence the efficacy of P. hermaphrodita

Slugs are serious pests in both agriculture and horticulture, and are a persistent problem for home gardens. They are usually controlled by pesticide pellets containing metaldehyde or ferric phosphate but these can have negative side effects on non-target organisms, including pets and wildlife. A more sustainable and ecologically sound alternative is the nematode Phasmarhabditis hermaphrodita. It has been formulated into a biological control agent (Nemaslug®) for use by farmers and gardeners to control pestiferous slugs. Nematodes are mixed with water and sprayed onto the soil, the nematodes search for slugs in soil and then infect and kill them. It has been available since 1994, and used regularly in the U.K. and Europe and can provide significant protection against slugs. However, there are reports of P. hermaphrodita not always working well in home gardens and in some field trials. It is unknown why there are these problems and there has been very little research into how control is affected by environmental factors. There are also problems when the nematode is faced with certain resistant slug species. Also there has been little research investigating whether alternative application strategies could be used to increase the efficacy of P. hermaphrodita to provide protection against slugs. Therefore, in collaboration with the Royal Horticultural Society (RHS), we propose the following objectives:

i) Examine the survival of P. hermaphrodita under different soil conditions– The effect of soil type, temperature, pH, moisture content on survival will be tested. The effect of predator and parasites will also be investigated. The influence of abiotic and biotic factors on the survival of P. hermaphrodita in soil will be assessed using qPCR.

ii) Investigate different application strategies of P. hermaphrodita to improve control of slugs. – Lab and mini plot trials will be used to test different doses of nematodes, barriers of nematodes sprayed around plants, applying nematode-infected slug hosts and examining whether different formulations of nematodes could be used that may provide a gradual release of parasites rather than direct application via spraying.

iii) Assess efficacy of P. hermaphrodita in concert with other biological control agents. Other promising biocontrol agent of pestiferous slugs includes larvae of the fly Tetanocera elata and a number of other Phasmarhabditis species. The compatibility of these other agents with P. hermaphrodita will be tested in laboratory assays and glasshouse tests. These other agents could also be used in combination with P. hermaphrodita to enhance control of resistant slug species.

Ultimately, in collaboration with the RHS this PhD will provide insight into the factors that influence the efficacy of P. hermaphrodita when used in the field. It will provide information to gardeners about how to control slugs and improve the use of P. hermaphrodita. It will also, potentially, recommend an alternative application strategy that could provide more effective control.

Qualifications/ Skills Required:

Candidates require a 2:1 degree in relevant subject area. MSc qualification desirable but not essential.

The candidate must possess knowledge of experimental design and be confident in statistical analyses. The project will suit a candidate with a firm scientific background, practical lab experience and the ability to work independently. Knowledge and understanding of parasitology, particularly nematology, is desirable.

Full training will be provided to the candidate along with access to the broad knowledge and expertise held by the supervisory team.

Deadline:

The deadline for submission of applications is midnight of 20/7/2018