Tomato plays a critical role in meeting nutritional food requirements, generating income and creating employment for both the rural and urban populations in Kenya. However, its production is threatened by the Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici, root knot nematodes (Meloidogyne spp), Fusarium wilt-root-knot nematode complex and Tomato leaf miner (Tuta absoluta) among others. Yield losses of 80-100% in some instances, have been reported due to the Fusarium wilt -root knot nematode complex. Field experiments were set up in two sites (Kagio and Mwea) in Kirinyaga County in Central highlands of Kenya to evaluate the effectiveness of various Integrated Pest Management (IPM) packages for the management of fusarium wilt-root knot nematode disease complex in tomatoes. The trials were established in two seasons, the long rains (March -July 2016) and the short rains (September 2016-January 2017). The IPM packages tested were NatuGro system (a combination of soil improvers, plant biostimulants and Trichoderma harzianum T22), a fungicide (carbendazim), Nemix (Bacillus sp. based biocontrol agent) and bionematicide (Paecilomyces lilacinus T251) applied either singly or in combination. Root knot nematode (RKN) gall index, as a measure of nematode disease severity was assessed twice during the experimental period; at flowering and mid fruit stage, while severity of fusarium wilt was assessed using the vascular wilt rating scale of 0-5. Fusarium wilt incidence was evaluated biweekly from 2 weeks after transplanting by visual assessment of wilt symptoms and expressing them as a percentage of total number of plants per plot. Both total and marketable tomato yields were determined at the end of the experimental period (4 months after transplanting). Integrating NatuGro system, Carbendazim and P. lilacinus was most effective in reducing RKN disease severity and damage and improving tomato growth followed by NatuGro system applied singly. Fusarium wilt severity and incidence were low throughout the experimental period and in all the treatments in both experimental sites.

Snap bean farmers mainly rely on chemical pesticides to manage insect pests but the introduction of strict maximum residue levels (MRLs) by European markets poses a challenge to the use of pesticides. This has necessitated the search for alternative pest management options that do not result in harmful residues on produce. Therefore, this study was carried out to determine the efficacy of potassium salts of fatty acids as alternative to synthetic chemicals in management of snap bean pests. Field experiments were carried out in farmers' fields in Mwea and Embu for two cropping cycles between July 2013 and January 2014. Potassium salts of fatty acids at 0.5%, 1% and 1.5% spray solution was compared with chemical pesticide confidor ® (Imidacloprid) and farmers practice [Thunder ® (Imidacloprid + Betacyfluthrin) and Karate ® (Lambda Cyhalothrin). Population of thrips, whitefly, and yield of pest damaged pods, in addition to marketable pod yield was determined. Application of potassium salts of fatty acids at 1% and 1.5% significantly (P<0.05) reduced white fly and thrips populations by up to 54%. Weight of pest damaged pods was also significantly (P<0.05) reduced by up to 76% while the weight of marketable pod yield was significantly (P<0.05) increased by up to 112%. The results demonstrated that potassium salts of fatty acids are a viable alternative to synthetic chemical pesticides thereby enabling farmers to produce with acceptable residue levels that meet market requirements.

Combination of pest management strategies that minimize pesticide use and conserve natural enemies is important for a sustainable environment. Overreliance on synthetic insecticides in the management of Tuta absoluta has led to pesticide resistance leading to difficulties in managing the pest. In this regard, alternative measures need to be put in place to reduce the effects of this pest. The objective of this study was, therefore, to assess the effectiveness of host plant resistance, biological control, and selective insecticides when used in combination, in the management of T. absoluta in tomato production. The study was set up in a greenhouse in a completely randomized design involving two tomato varieties, an insecticide (chlorantraniliprole), and a biological control agent(Macrolophus pygmaeus), applied singly or in combination. Data were collected on T. absoluta damage from the lower, intermediate, and upper leaves. The results from this study show that a combination of insecticide with a moderately resistant variety had a significantly lower T. absoluta damage as compared with a susceptible variety combined with an insecticide. However, the moderately resistant variety when combined with insecticide showed no effect when the biological control agent was added. The susceptible variety significantly reduced T. absoluta damage when combined with the biological control agent. These results indicate that treatment combinations in insect pest management can be utilized. The present study results indicate that using a moderately resistant variety (Riogrande VF) in combination with the insecticide chlorantraniliprole (Coragen®) and a susceptible variety (Pesa F1) in combination with the biological control agent (M. pygmaeus) can improve T. absoluta management. Under good habitat management, the susceptible variety will perform equally as the moderately resistant variety due to suppression of the T. absoluta populations by natural enemies. These findings show the importance of environmental conservation both by enhancing natural enemy abundance and use of selective insecticide in the management of T. absoluta in tomato production. Combinations in this present study are likely to reduce insecticide doses, thereby reducing the cost of production and enhancing environmental compatibility with natural enemies.