| dc.description.abstract | Tomato, (Solamun lycoperscicum) is a widely grown and consumed fruit-vegetable. It is susceptible to pest infestations that is usually controlled by pesticides use, especially imidacloprid (IMI), whose residues negatively impacts the environment and human health. Despite its low toxicity to humans, IMI bioaccumulation causes human health issues. Although widely used in Kenya, IMI use was banned by EU since it contributed to bee population decline. Even though exported agricultural products are often screened to meet international market limits, it is not practiced for locally consumed produce, this may lead to consumer exposure and subsequent poisoning. There is a need to compare IMI residue levels in local produce with EU/Codex-MRL to ensure safety and conformation to required standards. Kimira-Oluch Smallholder Farm Improvement Project (KOSFIP) is an irrigation scheme producing tomatoes in Homa Bay County. Farm gate tomatoes from KOSFIP have not been evaluated for safety and/or if they meet the EU/Codex-MRLs. It is not documented if KOSFIP farmers observe Good Agricultural Practices (GAPs) or IMI residue levels at farm-gates meet EU/Codex-MRL. Sometimes farmers use higher IMI concentrations and/or fail to observe minimum pesticide post application period (PAP). IMI recommended rate and PAP used at KOSFIP were developed in different environments. It is not known whether they suit the KOSFIP environment and/or influence residual IMI. This study assessed IMI residue levels in tomatoes at farm-gates and compared the levels with EU/Codex limits; determined influence of application rate and PAP on residue levels in KOSFIP tomatoes. Cross-sectional survey using random sampling method was used to sample tomato farmers applying imidacloprid. A 4x5 split-plot design in RCBD layout replicated thrice was used to determine effects of rates (0, 2.5, 5, 7.5 g/20L) and PAP (0, 2, 4,7,10 days) on IMI levels. Samples were prepared by QuEChERS method, residues analysed using LCMS/MS and data subjected to ANOVA using GenStat program. Results were compared with EU (0.3 mg/kg and Codex (0.5 mg/kg) limits. Approximately 62.9% of farm-gate samples had residues below EU-MRL and 92.9% below Codex-MRL, demonstrating most farmers were observing GAPs. Imidacloprid residues increased (p≤0.05) with high application rates and short PAP. Rates higher than the recommended had residue levels above EU-MRL. Recommended rate of application (5 g/20L) and PAP (3 days) are suitable for use in KOSFIP. Continued use of IMI at KOSFIP should be done according to GAPs and regular monitoring of GAPs implementation be prioritized. | en_US |
