Farmer’s knowledge: Armyworms invade Kigali

It should never take the farmers off guard. Ignorance has been the undoing of most farmers in developing countries, for they realise pests and their effects when it is too late.

It should never take the farmers off guard. Ignorance has been the undoing of most farmers in developing countries, for they realise pests and their effects when it is too late.

Army worms can be so disastrous to unimaginable proportions and unfortunately very few farmers are aware of this.

With the rainy season, different lawns or compounds armyworms have worked their way attacking different parts of the city. Army worms are moth larvae (caterpillars) that are pests of lawns or grass.

They are called army worms mainly because they ‘march’ in big numbers over an area, feeding on grass in large masses and moving to the next grassy area to continue feeding.

Their favourite foods are turf grass and grains and the cool weather helps them to increase in number. Infestation of these thousands of worms occurs in the grassy areas where they feed on leaf blades.

Noticeably these caterpillars are brown and black in colour and have a light stripe running down each side, from 0.25-2.5 inches long.

During the day they may ‘march’ onto driveways or even in the houses. Reports indicate that quantities of over 100 caterpillars can exist per square foot. At full size, they move awfully quickly and are capable of destroying a farm field in 48 hours.

On a positive note however, even though the worms may exist in some parts of the country like Kigali, the Rwanda Agricultural Development Authority (RADA) says they are on high alert.

“We are always equipped with the pesticides such that we spray them the moment we hear of their existence in the country. There is therefore no way the worms can affect the agricultural sector and as a matter of fact we are going to spray any affected areas.” Patrice Hakizimana, the Director of RADA said.

Their interim existence may not be rendered significant but the worms are as dangerous as they are capable of feeding on leaf blades to the grass root level.

Where they have been, the worms have destroyed several hectares of crops. It is reported that over 45,000 hectares of crops in different parts of Tanzania were attacked by the worms and posed as a drought threat.

According to the Daily Nation — Nairobi, Kenya, the worms have destroyed crops and pasture in 11 districts of the Eastern province this year. They are currently threatening food security in upper Eastern region and Tharaka division in Meru.

Armyworms deposit their eggs on or near plant foods and their egg masses may contain over a hundred new worms. Each female may deposit several of these clusters. The eggs are green at first but later change to brown. They are often covered with moth scales and hatch on an average of 11 days.

In the early stages the larvae tend to congregate but as they age they scatter in search of food. The larvae feed mostly at night or on cloudy days. If the plant is young and succulent, the army worm will eat it to the ground. You may recognize them by their yellow stripes and colour.


Army worms are definitely a threat to food security and destruction to Pastures which are also very crucial to the economy. There is need to wipe them out the moment they invade.

Immediate spray of an infested area with pesticides controls the worms at the egg and larvae stage, before they develop into pupae and become moths.

Any pesticide that lists armyworm control on the label can be used to spray lawns. Pesticides products may contain the active ingredients diazinon, carbaryl, acephate, or chlorpyrifos.

It is also recommended that the liquid form of the insecticide be sprayed in the late afternoon or evening. The grass should not be watered or mowed for 1-3 days after the pesticide treatment.

Everyone needs to be on the look out by scouting their farms and pastures often. Scouting for armyworms is an easy process and this can be done just by walking through the fields and critically analyzing the type of caterpillars feeding on the pastures or on the farm.

Farmers have got to be knowledgeable so that in case of any attack they immediately blow the whistle. Protection of oneself is very important before applying the pesticide.


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