Journal of Agricultural Science and Practice Volume 4(2), pages 29-42, April 2019 Article Number: AC46B7712 https://doi.org/10.31248/JASP2019.124 ISSN: 2536-7072 http://integrityresjournals.org/journal/JASP Full Length Research Ecological limits and management practices of major arthropod pests of tomato in Kenya Willis. N. Ochilo 1* , Gideon. N. Nyamasyo 2 , Dora Kilalo 3 , Washington Otieno 1 , Miriam Otipa 4 , Florence Chege 1 , Teresia Karanja 5 and Eunice K. Lingeera 6 1 Plantwise, Centre for Agriculture and Biosciences International (CABI), Canary Bird, 673 Limuru Road, Muthaiga, P.O. Box 633-00621, Nairobi, Kenya. 2 School of Biological Sciences, University of Nairobi (UoN), Nairobi, Kenya. 3 Department of Plant Science and Crop Protection, University of Nairobi (UoN), Nairobi, Kenya. 4 Department of Plant Pathology, Kenya Agricultural & Livestock Research Organization (KALRO), Nairobi, Kenya. 5 Plant Protection Services Division, Ministry of Agriculture, Livestock, Fisheries and Irrigation, Nairobi, Kenya. 6 Department of Phytosanitary, Kenya Plant Health Inspectorate Service (KEPHIS), Nairobi, Kenya. *Corresponding author. Email: W.Ochilo@cabi.org; Tel: +254 (0)20 2271000/20; Fax: +254 (0)20 4042250. Copyright © 2019 Ochilo et al. This article remains permanently open access under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 4th February, 2019; Accepted 28th February, 2019 ABSTRACT: In Kenya, tomato is cultivated for home consumption, as a cash crop, and a source of vitamins. In recent years, the growth rate of tomato production in the country has increased. Yields, however, continue to remain low due to a myriad of constraints, including incidences of arthropod pests. This paper catalogues arthropod pests of tomato in Kenya, establishes the pests’ distribution patterns in relation to spatial and temporal dimensions and documents practices employed by farmers for their management. The study relies on plant health clinics as primary providers of data. Relationship between variables is proved using multinomial logistic regression. A diverse range of arthropod pests was found to hamper tomato production in Kenya. Tomato leaf miner, whiteflies, and spider mites emerged as the major threats to the sustainability of tomato production. Most of the arthropod pests reported were associated with upper and lower midland agro-ecological zones. The reverse, however, was true for upper highland zones. For the management of arthropod pests, essentially, the use of synthetic pesticides was the preferred practice by farmers. The study underscores the need to consider variations in arthropod pests’ risk, both spatially and temporally when designing their management strategies. Also, alternative management procedures to the use of highly hazardous pesticides and better assessments of potential profit-loss to a smallholder for application and non-application of highly hazardous pesticides are required. Keywords: Arthropod pests, pest management, smallholder farmers, spatio-temporal, tomato distribution. INTRODUCTION Tomato (Lycopersicum esculentum Mill.) is a popular food crop cultivated and consumed worldwide (FAOSTAT, 2018; Gogo et al., 2012). In Kenya, the crop, cultivated in almost every homestead for home consumption, serves as an important cash crop for both small and medium scale commercial farmers, and as an important source of vitamins (Gogo et al., 2012). In addition to vitamins, tomato is also rich in antioxidants, including lycopene, carotenoids, phenolics and ascorbic acid, which can play an important role in averting cardiovascular diseases and cancer (Kirsh et al., 2006; Oduor, 2016; Toor and Savage, 2005). Tomato thrives under warm conditions (Oduor, 2016). The ideal soil temperature for seed germination is 20 0 C or above; below 16 0 C germination is extremely slow. The optimal daily maximum air temperature for vegetative growth, fruit set and development is between 25 0 and 35 0 C