Morphological and Molecular Characterization of Fall Armyworm, Spodoptera Frugiperda, From Selected Regions in Kenya.

Purpose: This study was done in Kenya for the purpose of confirmation and tentative identification of fall armyworm to help in proper monitoring and effective management of the pest. To achieve this, the study was organized in order to characterize Spodoptera frugiperda (fall army worm) found in Kenya using morphological and molecular techniques and determine prevalent strain of Spodoptera frugiperda in eastern and central regions of Kenya. The study was also organized to compare the host diversity for Spodoptera frugiperda strains in eastern and central regions of Kenya. Methodology: The study was a cross-sectional study which was conducted in 5 regions namely; Machakos, Nyeri, Murang’a, Embu and Kiambu. Sampling of sub counties was done followed by random choice of at least 2 villages and eventually reaching the actual households. Questionnaires were used to interrogate farmers about their knowledge on fall armyworm and seeking permission to check and pick the fall armyworm from their farms. Samples of moths and larvae were obtained. The pest was identified morphologically in the field before being taken to the lab for DNA was extraction and COI gene amplification. The amplified DNA was shipped to Macrogen, Netherlands for sequencing. Findings: This study confirmed actual establishment of Spodoptera frugiperda in eastern and central Kenya using COI gene amplification and analysis. Phylogenetic analysis indicated the presence of both the “Rice” and “Corn” strains. Results indicated higher prevalence of the Rice strain at 77.8% while that of Corn strain was 22.2%. Investigation of the host plants for the fall armyworm gave no evidence of plant host specificity for R- strain since it was also found in Zea mays (maize). Only two plants species, maize and sorghum, were found to host Spodoptera frugiperda in the study region, with a higher preference towards the maize crop. Unique Contribution to Theory, Policy and Practice: The findings of morphological and molecular characterization together with phylogenetic studies confirms presence of rice and corn strains of Spodoptera frugiperda in Kenya. The pest was recorded mainly in maize and sorghum crop and due to its host range in its native Western Hemisphere and migration ability it may spread to other crops like millet, rice, cotton, vegetables etc. Host status should be continuously investigated. It was also found that Spodoptera frugiperda has established itself in central and eastern regions of Kenya meaning that permanent solution to control its effects have to be developed.