Host plant penetration, development and life cycle of a Heterodera schachtii population from the Western Cape province, South Africa

Abstract

Heterodera schachtii (Tylenchida: Heteroderidae), also called the sugar beet cyst nematode, are of economic importance worldwide. Oilseed rape (Brassica napus L.), which is a crop of global importance, suffers yield loss when it is infected with H. schachtii. The first report of the occurrence of H. schachtii in South Africa was made in 1968 on the Greater Cape Flats of the Western Cape province of South Africa, showing the widespread occurrence and the high nematode numbers on cabbage, cauliflower, beetroot and Brussels sprouts. The penetration, development and life cycle of a local H. schachtii population on seven vegetables (beetroot, broccoli, Brussels sprout, cabbage, cauliflower, lettuce and turnip) and three weeds (black nightshade, purslane and shepherd’s purse) commonly grown, or found, in the Greater Cape Flats region of the Western Cape, South Africa, and two candidate trap crops (white mustard and oilseed radish) were examined under laboratory conditions. All the vegetables and weeds were found to be good hosts of H. schachtii, with the exception of lettuce, which was found to be a non-host. Oilseed radish and white mustard allowed penetration and some nematode development, but no, or little, cyst formation. Female bodies filled with eggs were observed from 31 to 34 days after inoculation onwards on all the vegetables and weeds, except for on beetroot, on which female bodies filled with eggs were observed a few days later. The results from this study are important, especially in terms of the adaptation of vegetable crop rotation cycles that are practised on the Cape Flats, so as to prevent the build-up of H. schachtii populations in agricultural settings.