Spread and impact of fall armyworm (Spodoptera frugiperda J.E. Smith) in maize production areas of Kenya

Abstract

Fall armyworm (FAW), one of the most important pests of maize in Latin America, suddenly appeared in Africain 2016 andspread rapidly.Estimates ofcrop losses dueto FAWare essentialin orderto compare the impactoftheselosseswiththecostofcontrollingFAWandadviseappropriatetechnologydisseminationandpolicy.Inthisstudy, therefore, crop losses due to FAW in 2017 and 2018 were estimated in all the maize production areas ofKenya. Data were collected during June and July 2018 through 121 group discussions with 1439 farmers,separately with men (697) and women (742), in communities that were randomly selected to represent themajor maize growing areas. The results showed that most participants (82%) could correctly identify the FAWfrompictures.By2016,FAWwasobservedbymorethanhalfofthecommunities(53%),with mostof theotherhalf first observing FAW in 2017. The proportion of farmers affected by FAW substantially increased, from thelong rains of 2017 (63%)to the long rainsof 2018 (83%), andin allzones exceptfor the high tropics andmoistmid-altitudes. However, the percentage of loss experienced by affected farmers decreased slightly, from 54% in2017 to 42% in 2018. In 2017, the low- and medium-potential maize-production areas were the most affected,withlossesof>50%,withhigh-potentialareasfacinglossesofabout30%,resultinginatotallossof37%forthewhole country. In the main 2018 season, losses in the low- and medium-potential areas were less – about 20%,butthe high-potentialareas werenowmore affected,leadingto atotalestimate of 33%.Weconcludethat FAWhas suddenly become a major pest in Kenya, causing losses of about a third of the annual maize production,estimated at about 1 million tonnes