Once considered a pest plaguing only North and South America, the fall armyworm (FAW) arrived in Africa in force in 2016, likely arriving in Nigeria through imported produce. Capable of flying 100 km overnight and laying 1,000 larvae in 10 days, the armyworm has now spread across the African continent in two years, leaving only four countries in sub-Saharan Africa yet to report infestations as of March 2018: Eritrea, Lesotho, Mauritius, and Seychelles.
The fall armyworm feeds on more than 80 different crops including maize, rice, sorghum, sugarcane, vegetables, and cotton. Within maize, a key food staple in sub-Sarahan Africa, the Centre for Agricultural Bioscience International (CABI) estimates that the pest could cause losses in 12 key Africa countries of 8.3 million to 20.6 million metric tons of maize annually, seriously threatening the food supply for up to 100 million people in those 12 countries alone.
The latest monthly update from USAID shows that FAW continues to be a problem to maize and other crops in southern and eastern Africa:
- In Ethiopia, the pest had infested in 13% of the maize fields planted as of late March 2018, with only 40% of the infested fields receiving some form of chemical treatment or cultural means. In the 2017 cropping season, FAW infested more than 24% of the 2.9 million hectares planted to maize, with a total loss of more than 134,000 tons of crop worth almost $30 million. This outbreak has affected millions of smallholders across the country and prompted the Government of Ethiopia to prioritize implementation of the 2018 FAW work plan.
- In South Sudan, FAW was detected in early planted maize crops in Western Equatorial State during late March 2018, with the pest expected to continue appearing over vast areas of the country as planting progresses.
- In Kenya, FAW outbreaks were reported in Kericho, Nyeri, Embu, Nakuru, and Meru counties attacking early planted maize. Control operations were launched by the affected farmers.
- In Tanzania, the pest was reported in most regions of the country and control operations are being carried out by the affected farmers with technical and material assistance from the Ministry of Agriculture.
- In Somalia, FAW has been reported in irrigated sorghum already this cropping year.
- In Madagascar, FAW was first reported in November 2017. FAO dispatched an assessment team early March 2018 to conduct assessments and provide training.
FAW will remain a threat to irrigated and rain-fed maize and other crops across several regions in Africa during the next six weeks. This threat is most prominent in countries with bimodal rainfall patterns and in irrigated crops which allow uninterrupted presence of host plants for the pest to survive and continue breeding and cause damage to crops.
For the 2018 season, combinations of precipitation, warm weather, and green vegetation must be closely watched as this mix coupled with the seasonal wind trajectory can favor breeding and facilitate migration and further spread of migratory pests.
The map to the right shows daily precipitation anomalies across selected countries in east Africa with those areas in blue receiving significantly more rainfall than normal, resulting in greater vulnerability to FAW infestation.
Those areas shaded in red may be less susceptible to FAW due to reduced rainfall, but the drought-stricken areas are at significant risk for reduced yields this season due to inadequate moisture.
Active surveillance, monitoring, routine scouting, and control interventions remain critical to counter the potential of major crop losses due to FAW.
Tools to Counter the FAW Invasion
Although FAW has long been a pest in North and South America, farmers there can control the pest with integrated pest management (IPM) and technologies such as genetically modified (GM) seeds and insecticides.
African smallholder farmers are facing a pest that is new to them and spreading rapidly, and they often lack access to timely information, training, and safe and effective pesticides. Available tools consist of crop rotation and insecticides. When other options are unavailable, some smallholder farmers have used natural products such as neem oil, pepper, or wood ash with varying levels of efficacy.
CABI has recently launched a new project which takes a three-pronged ‘defend, detect and defeat’ approach to combating FAW. A push-pull technology they are testing with selected forage crops such as greenleaf desmodium and Napier grass shows some positive results as part of the ‘defeat’ strategy, but this cultural practice is not an immediate fix when the insects appear unexpected.
FAO has developed a mobile app to enable farmers, extension workers, and other partners to help identify and map the spread of FAW in Africa, as well as sharing measures that are most effective in managing and controlling the pest.
Call to Action
Coordinated and holistic systems are needed to reduce the looming threat given the surprisingly quick invasion across the African continent, the significant possibility for high yield loss, and the environmental factors favoring the FAW infestations this season.
The global private sector, universities and research centers, foundations, civil society organizations, and other development partners are needed to join Africans to effectively combat FAW. Growers in North and South America successfully control FAW using an array of IPM strategies, including conventional host plant resistance, biotechnology, pesticides, and biological control.
The U.S. Government’s Feed the Future program is looking for digital solutions that can help identify and provide actionable information on how to treat FAW in Africa and have created a contest to reward the best solutions. Innovations that could assist in the battle against FAW can be submitted to the Fall Armyworm Tech Prize contest by May 14, 2018.
More information is available at this link: feedthefuture.gov/lp/partnering-combat-fall-armyworm-africa.
Lifting existing bans on GM crops on the continent could lead to improved control of FAW. GM technology such as Bt corn has revolutionized insect pest management in the U.S., Brazil, Argentina, and many other countries.
GM crops do not yet have regulatory approval in most African countries, according to Mark Edge, Director of Collaboration for Developing Countries at Monsanto. “Bt maize was introduced over 20 years ago, and has now been in South Africa for 15 years,” shared Edge. “However, Bt as an applied biological control has been around for over 50 years, and has been used around the world by farmers and gardeners as an insect control product. Bt corn would be an excellent addition to the crop protection toolbox for farmers in Africa.”