The use of brassica species for the management of potato cyst nematode infestations of potatoes

Ngala, B.M. (2015) The use of brassica species for the management of potato cyst nematode infestations of potatoes. Doctoral thesis, Harper Adams University.

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Abstract

The potato cyst nematodes (PCN), Globodera pallida and G. rostochiensis are economically the most important nematode problems of potatoes within the EU, costing the UK potato industry over £36 million based on yield loss and nematicides application. Historically, farmers within the UK have relied heavily on soil fumigant and granular nematicides for PCN control. However, increasing political pressure on pesticide usage means that alternative and sustainable strategies are required. Biofumigation, the suppression of soil borne pests and pathogens by biocidal compounds released when brassicaceous tissues are hydrolysed, offers a potential sustainable alternative in managing PCN. In this study, summer cultivated B. juncea and R. sativus reduced PCN population post-potato harvest. Eruca sativa proved to be cold tolerant following overwinter cultivation, but did not reduce PCN multiplication . Glucosinolate concentrations in the brassicas varied significantly between different plant regions and cultivation seasons. B. juncea leaves produced high 2-propanyl levels while R. sativus produced predominantly 4-methylsulfinylbutyl and 2-phenylethyl GSL in foliage and root respectively. Eruca sativa produced a blend of GSL in both above and below grown tissues, most of which were either low or non-ITC producing GSL. Metconazole application enhanced 2-propanyl GSL production in B. juncea tissues. Glucosinolate concentrations correlated positively with PCN mortality in the summer-cultivated experiments. In glasshouse experiments, sinigrin was significantly degraded in brassica cultivated soil pre- and post- incorporation of the brassicas. Positive relationships were observed between PCN mortality and microbial activity, while GSL concentration was found to be inversely related to microbial activity. Finally, the LD50 for B. juncea and R. sativus against PCN were determined in-vitro as 0.027/0.032 and 0.546/0.035 mg 1 ml- for leaf/root extracts respectively. This study has demonstrated that using B. juncea and R. sativus can play an important role in PCN management, particularly if included in an integrated pest management scheme in ware potato production.

Item Type: Thesis (Doctoral)
Divisions: Crop and Environment Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 16 Nov 2018 16:10
Last Modified: 16 Nov 2018 16:10
URI: http://hau.repository.guildhe.ac.uk/id/eprint/17353

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