Evaluation of the efficacy of biofumigant crops for management of potato cyst nematodes

Biofumigation is a strategy which exploits plants, mainly belonging to the Brassica family, that produce compounds called glucosinolates. When the tissues of the plants are damaged glucosinolates are broken down and various volatile compounds, including isothiocyanates (ITCs), are released. ITCs have been shown to affect nematodes and their release is the basis of the biofumigation effect. A range of biofumigant crops are commercially available in GB and field trials have been completed to:

• determine the potential of biofumigant crops in Northern and Southern Britain
• optimise the incorporation of the biofumigants
• determine the effect of different nutrient inputs on glucosinolate profiles and the impact on PCN populations.

There were trials (Shropshire 2014/15 and Aberdeenshire 2014/15) where there was evidence of PCN suppression in plots where biofumigants were grown/incorporated. However, the results were variable across locations/seasons. 

Trials were carried out to assess the effect of nitrogen and sulphur inputs on biofumigation using brown mustard (Brassica juncea). At one of the two sites, the viability of PCN eggs was significantly lower in plots receiving 100-150 kg/ha N and 25-50 kg/ha S than in plots with other treatments. 

Results of the measurements of glucosinolate levels in biofumigant samples (Shropshire and Lincolnshire 2016/17) are provided in the Appendix to the final report.