The fall armyworm (FAW) plague, which has caused much damage on maize farms since first appearing in South Africa in December 2016, has now also found its way to soya bean crops.

Igni Bouwer, a Laeveld Agrochem agent in the Ermelo area, says the FAW was identified on a soya bean farm in the Dirkiesdorp district between Piet Retief and Wakkerstroom in Mpumalanga on 6 March 2017.  

"So far it seems as if the spread to soya beans in the area is only limited to one farm that has about 250 ha of soya beans under irrigation,” Bouwer said.

The FAW pest, which has made its way south through Africa since the beginning of 2016, and for the first time appeared in Limpopo, Gauteng and Mpumalanga in December 2016, has since spread to farms in all provinces except the Western Cape.

To date, the FAW has primarily caused damage to maize crops, although an isolated case of the infestation on potatoes was reported on 23 February in Loskop Valley in Limpopo. According to Potatoes SA, limited damage was caused.

According to a CropLife South Africa report released on the outbreak on 8 March 2017, the FAW has also been found in sorghum, cotton, some vegetables, probably in groundnuts and in natural veld around maize fields.

There have also been fears that the pest can find its way to the country’s sugarcane plantations, but according to Cedric Mboyisa, South African Sugar Association's (SASA) Communications and Media Manager, the fall army worm has not yet been found on any sugarcane crops.

The summer edition (January – March 2017) of the South African Sugar Journal reports that 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 report concluded.

Professor Mark Laing, senior professor and director of the African Centre for Crop Improvement at the University of KwaZulu-Natal, says the FAW has a wide host range and it will attack crops like potatoes. “However, it does not really like the vegetable and rather prefers grass cuts.”

Corné Liebenberg, marketing director at Laeveld Agrochem, said that in order to control the spread of the FAW pest, early detection is essential and that FAW-specific insecticides must be applied in the early stages of the larvae’s development.

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“It is very important to stay updated and to only use insecticides that are registered and recently confirmed to be effective against FAW as resistance to even some relatively new active ingredients has appeared. Furthermore, as with all Lepidopteran pests on maize, corrective control after cob and stalk penetration is not possible,” says Liebenberg.

He said Laeveld Agrochem, which assists with crop protection and precision farming, has agents throughout South Africa who are ready to assist farmers with solutions to the FAW problem or any other enquiries they may have.

Farmers can call the Laeveld Agrochem emergency number on 060 458 8483.