Elita Chikwati Senior Agriculture Reporter
Government has distributed Carbaryl 85 Wettable Powder across the country for the control of the fall armyworm that has wrecked havoc in most areas with an irrigated maize crop.
The pest, which is new in the country, has affected maize in Midlands and Matabeleland provinces.
Ministry of Agriculture, Mechanisation and Irrigation Development, department of Plant Protection and Research Institute chief entomologist, Dr Godfrey Chikwenhere, yesterday expressed concern that the pest had 12 cycles and could continue recurring after the first spray.
He urged farmers to continue scouting their crop even after spraying.
Dr Chikwenhere said the fall armyworm should be controlled during the early days of its life to reduce the rate of recurrence. He said if left to grow, it would require more chemicals for control and could also become resistant to the chemicals.
“We have two types of worms that affect maize namely fall armyworm and the African armyworm. The fall armyworm is the current challenge and can have between 10 and 12 cycles.
“The pest is controlled by Carbaryl 85 WP and this is a contact pesticide. The chemical should come into contact with the worms for effectiveness.
“Farmers should spray the crop when it is still young, below the knee level stage. This is the time when Carbaryl will be most effective,” he said.
Dr Chikwenhere said the fall armyworm lays between 50 to 300 eggs under the leaves.
He said when scouting for the pest, farmers should check underneath the leaves.
“They should check for a whitish cluster. The cluster turns blackish when the eggs are about to hatch. Farmers should spray the cluster.
“It takes 30 days for the pest to develop from the egg into an adult. The eggs hatch earlier under hot conditions and this may cause overlapping of cycles,” he said.
Dr Chikwenhere said farmers should use the chemicals correctly to control the pest so it does not develop resistance.
“If not controlled properly there can be re-infestation and the fall armyworm may go on to attack the cob. The pest should be sprayed when it is still young. Farmers should not irrigate immediately after spraying and also should not spray when they expect rains as the chemical will be washed away,” he said.
He said the country could soon experience a dry spell and there were fears of another outbreak of the fall armyworm.
The fall armyworm’s larvae or caterpillar is pest of maize, sorghum, sugarcane and other cereals.
It is regarded as a pest and can wreak havoc on crops if left to multiply. The pest was first reported on the African continent in several West African countries.
The Alien invasive moth is native to tropical and sub-tropical regions of the Americas.
Caterpillars of fall armyworm seem to be much more damaging to maize than most other species.
Fall armyworm has a remarkable dispersal capacity of over 2 000km per year.
Use of selected insecticides and non-selective use will lead to the emergence of resistant pest populations.
Alternated application of insecticides such as pyrethroids, carbamates and organophosphates are recommended as immediate measure.
Controlling of fall Armyworm with Carbaryl 85 percent WP at 300-400grammes per 15 litres of water will effectively control the pest at full cover spray.