Fall Armyworm(Spodoptera frugiperda) Occurs in Western Zones of Oromia
Contributed by:
Tafa Jobie, Director for Crops Research, IQQO-Oromia Agricultural Research Institute and Mengistu Oli, Senior Crop Protection Expert, Oromia Bureau of Agriculture & Natural Resources
The fall armyworm (Spodoptera frugiperda), is a tropical insect pest and endemic to the Western Hemisphere, ranging from Brazil northward, throughout Central America and North America. It has never occurred in Ethiopia, but it is recently (February 2017) recorded on maize, for the first time, in Sheka Zone of the Southern Nations, Nationalities and Peoples Regional State of Ethiopia. Now it further advanced in Jimma, Badalle and Wallaga Zones of Oromia. The Western zones of Oromia grow significant acreage of irrigated maize, which has created favourable conditions for quick reproduction and progress of the pest. Prior to its occurrence in Ethiopia, the pest has been reported to occur in several African Countries: Zimbabwe, Malawi, Mozambique, Namibia, South Africa and Zambia.
This lepidopetran pest, like many others, is polyphagous and can live on over 80 species of crops and weeds, and can move over 300 miles per generation. Warm, humid and heavy rainfall favors its reproduction. Fall armyworm is nocturnal and mating occurs during the night. After a preoviposition period of three to four days, the female normally deposits most of her eggs during the first four to five days of life, but some oviposition may occur for up to three weeks.
Eggs are laid in cluster, mainly on the underside of leaves, covered by dense scales. Like most of insects, it has four stages to complete lifecycle (see fig below) and hatch in two to four days when the temperature is in the range of 21-27 degree Celsius. The larva has six developmental instars, often the older stages causing higher damage proportioned to over 70% of the overall damage. A single larva can chew out about 140cm2 of maize leaf area to complete the larval development period. Fully developed larvae pupate in soil at depth of 3-10cm. When the soil is too hard to penetrate, the larva may pupate above the ground by webbing together leaf debris and other materials to form a cocoon on the soil surface.
Ongoing Activates to Control the Pest
Oromia Bureau of Agriculture and Natural Resources conducted a series of intensive surveys in the affected zones and confirmed its presence in many districts of Jimma and Badalle zones. Recently, reports show that the pest is occurring in Wallaga Zones. To follow up its prevalence and to control the pest, The Bureau has established two Committees - a Steering Committee, whose members are senior bureau heads and leaders from the bureau of Agriculture and natural Resources, Oromia Agricultural Research Institute, Oromia Seed Enterprise, Oromia Irrigation Development Authority and others, The second one is a Technical Committee and it is composed of senior experts and researchers from the same institutions.
The Technical Committee conducts frequent surveys to update the status of the pest in already affected as well as new areas and presents the reports to the Steering Committee to enhance decisions and plans towards the control operations. The Steering Committee plans for the volume of insecticides required to control the pest and its effective distribution. The Technical Committee is mandated to carefully follow up the situation in affected areas and in all areas that are likely to be affected in the commencing main season.