Potato cyst nematodes are highly damaging parasites of potato. Management options are limited and rely heavily on the use of nematicides. These products have an uncertain future due to evolving EU legislation. Biofumigation using brassica cover crops is a promising crop protection strategy that can be used to reduce soil borne pests, pathogens and weeds. The project described herein will evaluate the application of biofumigation for the management of potato cyst nematodes in Great Britain.
Potato cyst nematodes continue to pose a major threat to the economic production of potatoes. At present it is conceivable that some nematicides will be lost due to evolving EU legislation. The Potato Council have calculated that losses from PCN damage would rise from £25.9 million to £58.2 million if nematicides became unavailable. Research is therefore needed to develop effective alternative control measures to protect future potato crops.
Biofumigation is a strategy which exploits plants, mainly belonging to the Brassica family, that produce secondary metabolites called glucosinolates. When the tissues of these plants are damaged, glucosinolates become hydrolysed by an enzyme called myrosinase to release various volatile substances including isothiocynates (ITC’s). ITC’s are known to suppress numerous pest and disease organisms including PCN. The biofumigation method involves growing glucosinolate producing plants as a cover crop between crops in the rotation. Biofumigant plants are macerated and incorporated in moist soils to induce the production of ITC’s. Previous work has shown that ITC’s have suppressive effects on the juvenile stages and the encysted eggs of PCN. However, work is required to optimise the method under field conditions and to develop suitable guideline for potato growers. In particular, the incorporation of Brassica residues needs further investigation to determine the optimal conditions for glucosinolate hydrolysis and maximum retention of ITCs. Factors which may influence biofumigation efficacy include soil moisture/irrigation inputs and equipment used to macerate the foliage. Another aspect that needs further investigation is the role of cover crop inputs such as nitrogen and sulfur. Nitrogen will have a direct effect on crop biomass whilst sulphur may influence glucosinolate content. This project aims to optimise biofumigation for PCN management by:
The proposal also acknowledges that new Brassica biofumigant crops are regularly being released by commercial suppliers and therefore in addition to the field trials with existing biofumigants, polytunnel studies will be used to evaluate the efficacy of new potential biofumigants. Findings from all aspects of the proposed project will be underpinned by analysis of PCN viability.
SRUC, Barworth Agriculture