Zimbabwe farmers have been put on high alert of a potential African Armyworm (AAW) outbreak as a result of seasonal changes.
AAW moths come with the inter-tropical convergence zone (ITCZ) winds that bring rains into Zimbabwe from Tanzania.
In its latest advisory for the period extending December 11 to 17, 2022, the Agricultural Advisory and Rural Development Services said the pests sometimes manifest in large numbers and target maize, sorghum and other cereals.
“Farmers are urged to be on high alert for the African Armyworm (AAW) outbreak. The AAW moths come with the intertropical convergence zone (ITCZ) winds that bring rains into Zimbabwe from Tanzania.
“The notorious pests lay eggs in areas where host cereal crops (maize, sorghum, finger millet and pearl millet) and veld grasses are growing, causing extensive damage.
“Traditionally, invasions start from the northern parts of the country, notably in Muzarabani of Mashonaland Central, where the last outbreak was experienced.”
Previously, pest control has been made difficult due to limited knowledge by farmers, and thus agriculture extension officers now train or inform farmers on how to control and manage pests.
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According to the advisory, most damage is caused by gregarious caterpillars feeding on crops, which occur in two ways.
One is direct attack on young plants less than 30cm high by larvae, which hatch from eggs laid on the crops or are carried by the wind onto the crops.
Secondly, through large scale invasions by nearly full grown larvae from adjacent infected grasslands, causing total destruction on older crops.
The pests damage crops at an early stage by chewing the leaves, creating small windows and or holes, leaving a high level of droppings in the process.
Integrated pest management (IPM) techniques are effective in the control of army-worm. These activities include monitoring pests by scouting fields daily to observe the level of infestation.
Also, others use light traps and field sanitation to attract adult male moths, thereby preventing mating with females.
Digging ditches at about 1,5 metre intervals to prevent migration of caterpillars from one field to another also helps.
Farmers may also use pesticide control measures when no other strategies are available to bring the pest infestations under control, authorities said.
