Following relatively early rains this summer, the Department of Agriculture is calling on all growers of maize and related host crops such as sorghum and sweet corn to take precautionary measures in controlling the Fall Armyworm (FAW).

Growers in Gauteng have found this invasive worm in some areas from 2017 and it is now present in all the provinces in South Africa, although levels of infestation vary.

The migratory worms are native to the United States, South and Central America and get their name from the way they march from grasslands to crops. They are also known as Amerikaanse Kommandowurm.

They are particularly partial to maize and can devour almost the whole plant. In its larval state, it attacks the leaves and damages the silk. It then proceeds to eat into the ear of corn from the outside and inside. It feeds at the base of the cob as well. Even the stem and the tassels receive its unwelcome attention. Larvae tend to hide from sunlight or move into shade or under cover.

Smallholders are urged to be vigilant to ensure early detection and enable timeous assistance. Precautionary control measures include diligent/vigilant scouting for egg packs, leaf damage and caterpillars as well as trapping, to ensure early detection for effective control of FAW. The moth can be caught in traps with a lure, which can also serve as an early warning of the presence of the pest.

An integrated pest management programme, with the use of biological and insecticide measures is the method to be adopted in the fight against this invasion. For the Guideline for Registered Agrochemicals to Control FAW click here.

It is best to start agrochemical spraying while the caterpillars are smaller than one centimeter (1cm) long. Big caterpillars (over 1cm) crawl deep into the leaf whorls of maize plants and that makes it difficult to reach them when agricultural chemicals are applied.

The main concern with this pest is that it can rapidly develop resistance to agrochemicals, thus it is highly recommended to rotate the agricultural chemicals within the cropping season.

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