By Amelia Genis
Armyworms are also striking farms in the Western Cape, where winter grain is being planted. The plague must be stopped before the grain starts to emerge.
Farmers here report that, so far, the worms have only eaten the ryegrass and couch grass that emerged after the autumn rain.
At the beginning of April, African armyworms were observed in the Northern Cape. Now, barely a month later, the worms have also been seen in the Western Cape, specifically on farms near Porterville, Riebeek West, Wellington, and Philadelphia.
Although it is unclear how the worms reached the Western Cape, it is speculated that the moths were driven south by air currents from thunderstorms.
The Australian Department of Primary Industries describes the moths on its website as “strong flyers that can be carried hundreds of kilometres in storms”. The larvae can also spread through cut flowers, fruits, and vegetables.
The insects can complete their life cycle in 23 to 27 days.
Cooler weather, fewer worms
W.G. Treurnicht from the farm NuHoop near Porterville says that although he doesn’t know how sensitive the worms are to temperature, many worms were present on his farm during the hot weather around Freedom Day. Now, with the cooler weather of the past few days, it seems the worms have decreased considerably.
He suspects that the warm weather after the good rain they received at the end of March and again in April has created favourable conditions for the worms.
Treurnicht says he’s not going to spray for now. “I don’t see worms where I’m busy planting. I suspect something is now unfavourable for the armyworms. Our night temperatures have dropped considerably.”
According to him, the planting conditions are currently very favourable. However, he has already established that the chemicals they can spray will not have any residual effect on the grain.
Don’t eat medics
Junior Herholdt from Uitkyk Boerdery in the Koeberg area says he hasn’t started planting wheat yet, but he has noticed that the worms eat grass, such as ryegrass and couch grass. They don’t eat the medics.
Although he has changed his production practices so that he no longer sprays insecticides and fungicides on his grain and pastures, in this case, he will spray a bollworm remedy to get rid of the worms.
“The worms just can’t get into the grains because then we have a nightmare. They eat the couch grass patches until they look like copper wire.”
He says the worms are only in the higher-lying areas against the hills, not the lower-lying areas.
Richard Hewett from Boesmansfontein near Wellington says he has already sprayed the worms on his farm.
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