The department of agriculture has confirmed the presence of “high numbers” of Fall armyworm moths as well as larvae near Clanwiliam in the Western Cape.
The discovery shows that the dreaded crop pest has now spread throughout South Africa.
Farmers in the province have been urged to step up surveillance and scout for the worm, especially as South Africa moves into autumn, the season during which the Fall armyworm migrates.
The Fall armyworm is found in Central and South America, where it is especially known for devastating maize and wheat crops. But it also feeds on sorghum, sugarcane, cotton, millet, and vegetables.
In the Western Cape it was detected in sweetcorn.
It was first detected in parts of Western and Central Africa in early 2016. By early 2017 it was wiping out entire crop fields in Zambia.
The UN Food and Agriculture Organisation has warned that it could have a serious impact on Zimbabwe’s food security.
One study has suggested the worm could cost Africa’s biggest maize producers up to a combined R75 billion per year in lost crops as it wipes out up to 60% of potential yields – but some experts think that is a conservative estimate.