Maize is under attack. This time it is not about the lethal maize necrosis, but the fall army worm. This deadly pest has invaded large swathes of land, causing havoc.
“We have never seen anything like this. The moth eats the crop so fast we have been unable to contain it,” a farmer in Soy complained.
Many farmers do not know what to do. Earlier attempts at applying usual contact pesticides to deal with what they assumed to be the stalk borer has been unsuccessful. What is baffling is the stubborn nature of the pest. While farmers are used to scouting for the worms outside of plants, the fall armyworm escapes detection by burrowing inside maize stems. This makes it difficult to control using pesticides.
Unlike armyworm, fall armyworm feeds during the day and night, but are most active in the morning or late afternoon. The pest which are most dangerous at larvae stage, feed and damage leaves and inside whorls of young maize plants resulting in small shot holes or large ragged and elongated holes on the plant.
Early detection
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This is the first time farmers are experiencing it. It is not your regular stalk borer or the African armyworm. So, controlling it means an entirely new approach.
Early detection of infestations will allow for more effective control of this pest.
Finding an infestation when it is too late to contain is a common problem. Because fall armyworm prefers whorl stage corn, late planted fields should be given a high priority when scouting.
Survey 20 consecutive plants (selecting the first randomly) from at least 5 locations in the field. Look for symptoms such damage to the leaves.
A few days to tasseling, look for large larvae in the whorls which will be pushed out when the tassels emerge. These larvae may attack young ears.
Continue to check for this insect until silks begin to dry.
Pherome traps
Pheromone traps are also useful remedies. In Zambia, where the pest has been declared a national disaster, farmers are putting sandy soil into the maize funnels. The sand is rough to the skin of the fall armyworm and can kill the larvae. They do this at first sight of damage.
Use of ash
Others are applying ash in the funnel of maize at knee height.
Chemical control
Chemical control if properly done can also be a remedy. But the experts are warning the pests can have 10 to 12 cycles and hence could continue recurring even after the first spray.
The Ministry of agriculture is recommending the use of the following insecticides; Diazinon, Alpha Cypermethrin, Chlorpyrfos, Diflubenzuron Triclorfon (Dipterex), Chlorantraniliprole, Spinetoram, Emamectin benzoate, Indoxacarba and Lambda Cyhalothrin.
For effective control in maize, spray at least three times starting two weeks after emergence, at knee high and just before tasseling.
However these products need to be used appropriately at right environmental conditions to minimise development of pest resistance.
Treatment
Treatments must be applied before larvae burrow deep into the whorl or enter ears of more mature plants.
Insecticide applications by ground rig using at least 30 gallons per acre and high pressure will give the best results. All farmers are further advised to spray neglected farms, which may become breeding grounds for the insect and a source of re- infestation. Given that the pest will continue with the frequency of drought conditions, as a preventive measure, the National government and the County governments should strengthen the monitoring and surveillance for this pest using pheromone traps.
