Rowan Stranack

Rowan Stranack is Extension and Biosecurity Manager at SASRI

Source: Department of Agriculture, Forestry and Fisheries

Fall armyworm Spodoptera frugiperda is a migratory lepidopteran (moth) species. It originates from the tropical regions of South America but is also present in some of the southern states of North America. 

Above: Fall armyworm (Spodoptera frugiperda) in its larval stage.

The main crop hosts of the pest are maize, sorghum, groundnuts, cotton and soya beans. The moth is a strong flyer but it is the larval (caterpillar) stage that causes the damage. In maize, the caterpillar stage is known to cause extensive damage to the leaf whorl, tassels, green leaves, sheaths and even emerging maize ears themselves. There are more than 80 different plant species also known to be attacked and sugarcane is among these.

Fall armyworm arrived on the African continent in 2016 and was reported from West and Central Africa where it caused serious crop losses, particularly in maize. Since then the pest has spread southwards where this year it has been recorded in the Limpopo, Gauteng, North West, Mpumalanga, Free State and Northern Cape provinces of South Africa. Maize, sweet corn and sorghum appear to be the main target crops. 

In recent weeks the pest has been recorded on maize in the cane belt of Mpumalanga and KwaZulu-Natal. However, the pest has not yet been found on sugarcane despite being found on maize in close proximity to cane. Specialists and Biosecurity teams from the South African Sugarcane Research Institute (SASRI) are on high alert and are monitoring sugarcane and adjacent crops. Should the pest attack sugarcane at some stage, control measures would be implemented. Without clear evidence that sugarcane is currently under threat, it is best that the pest be controlled in those crops where it is currently a problem. 

The Department of Agriculture, Forestry and Fisheries (DAFF) has issued numerous updates on the distribution and control of the fall armyworm and, should the problem escalate, the sugar industry will take guidance from DAFF in accordance with their Emergency Pest Response Plan.