The African armyworm (Spodoptera exempta) outbreak has been reported in the Gauteng, Mpumalanga, and Limpopo provinces, posing a significant threat to food security.
According to Roger Price, research team manager at the Agricultural Research Council, and Dr. Godfrey Kgatle, research coordinator at Grain SA, the destructive pest primarily feeds on grasses but may also target grains like maize and millet.
“The outbreaks have been observed in Groblersdal (Limpopo), Carolina and Badplaas (Mpumalanga), and Pretoria North and Bronkhorstspruit (Gauteng),” Price noted.
“The worms are transported by winds from Central Africa, making the issue widespread rather than isolated. They enter as moths, lay eggs, reproduce, and then die off before winter,” he explained.
While African armyworm outbreaks tend to be sporadic, they are relatively frequent. The severity of the infestations varies depending on the scale of outbreaks in Central Africa.
“This season, the infestation seems relatively small so far. Its full extent remains uncertain, but with colder weather approaching, fewer cases are expected,” Price added.
Pastures are particularly vulnerable to the pest, with livestock farmers urged to remain vigilant. When attacked by the African armyworm, kikuyu grass releases cyanide-like chemicals, making it toxic to cattle.
“When cattle graze on affected pasture, they can fall ill, and in some cases, large areas of pastureland can be completely destroyed by these ‘commando worms,’” Price warned.
Regarding management, Price noted that chemical spraying is not always cost-effective due to the vast areas affected.
“Infestations can cover extensive regions, making large-scale spraying impractical. However, if spraying is necessary, we recommend using synthetic pyrethroid insecticides,” he said.
On a more positive note, Kgatle assured maize farmers with crops beyond the tasseling stage that they need not worry too much.
“The African armyworm primarily targets younger, more vulnerable maize plants, especially when its usual pasture food is in short supply,” Kgatle explained.
However, he cautioned that if the pest migrates to younger maize crops in other provinces, the threat could become more significant.
