Suppressing Potato Cyst Nematode, Globodera rostochiensis, with Extracts of Brassicacea Plants

Abstract

The golden potato cyst nematode, Globodera rostochiensis (Woll) is responsible for large yield losses in potato crops in northern Portugal. Fumigation with synthetic chemicals controls this soil pest with possible negative impact on the environment. Thus, it is desirable to find environmentally friendly alternative measures to control this nematode species. Amending plant parts of Brassicaceae have been recognized as potential biofumigation practices. Active volatiles compounds released after enzymatic hydrolysis are responsible for the efficacy of biofumigants. The glucosinolate-myrosinase-isothiocyanates system appears to be controlling several soilborne pests and pathogens. The biological role of Brassicacea green manure amendments on potato cyst nematodes populations has not been reported in Portugal. In this study we evaluated the effects of two concentrations (0.2 and 0.05 µmoles 100 g−1 dry weight) of total glucosinolates of six plants extracts (broccoli, cauliflower, collards of Brassica rapa, collards of kale, Portuguese cabbage and watercress) on potato cyst nematodes population. The results were expressed as number of new cysts formed on bioassay Desiree potato roots. ANOVA analysis showed a highly significant effect (P < 0.001) of the plant extracts and concentrations tested on the suppression of potato cysts nematodes. The LSD test showed that the number of newly formed cyst on root system of bioassay plant was also related (P<0.05) to type and concentrations of glucosinolates extracts. The lowest numbers of cysts were recovered from potato roots that received extracts of watercress, cauliflower and B. Rapa, respectively. The cyst reduction appeared to be associated with high levels of 2-Phenthyl and 2-propenyl glucosinolates in these plants.