The Department of Agriculture, Land Reform and Rural Development (DALRRD) has issued an alert following the detection of Goss’s Wilt (Clavibacter michiganensis subsp. Nebraskensis) on maize in four provinces.
Goss’s Wilt is a bacterial disease, and there are no recorded fungicides that work against it. It can be managed by planting highly resistant maize hybrids, by reducing movement of infected stubble between fields, and by rotating host crops with non-host crops.
Goss’s Wilt was detected mainly in the Free State, North West, Gauteng and Eastern Cape.
According to the department, samples were collected after random surveys in collaboration with research institutions and government in the reported areas. The pest was positively identified by molecular techniques [Polymerase Chain Reaction (PCR) and sequencing].
“DALRRD is continuing with research in understanding the epidemiology and management of the pest to support local maize producers, while conducting delimiting surveys to determine the extent of the spread of the disease,” the department said.
Goss’s Wilt is regulated in terms of the Agricultural Pests Act, 1983 (Act No. 36 of 1983) and Control Measures R.110 as amended.
“Maize (Zea mays) is the only known economically important host of the pathogen. Over short distances, the disease can be spread within a field by contacting leaves on adjacent plants, while over long distances it can be spread through seed, even though seed-borne transmission has shown to be very limited,” the department explained.
It encouraged farmers and community members to practice effective cultural control and to reduce movement of infected stubble between fields.
It also advised international travellers to avoid illegal importation of agricultural commodities into South Africa as this may lead to the introduction of new pests and diseases that are expensive and difficult to manage.