Emerging Solutions to Challenges in Greenhouse Nematode & Plant Nutrition Tomato Production

Abstract

Tomato (Lycopersicon esculentum Mill.) is a high-value vegetable. However, nematode infestation and nutrient depletion are major constraints in greenhouse tomato production, causing 35% to 40% losses. Chemical control options in Kenya compromises environmental safety. This study investigated the impact of soil amendments with fresh biomass from Lippia kituensis Vatke (LK) and Ocimum gratissimum L. (OG) on Meloidogyne sp., tomato growth, yield and quality. Unbalanced pot experiment in factorial format, embedded in RCBD, with 4 levels of plant biomass replicated 3 times was used. Biomass rates were 0, 2%, 4% and 8% in 10 kg potted soil mixes, singly and in all possible combinations. Neem extract (Azadirachtin 0.3 w/w) was used as positive control. Nematode population reduced by 82.2% at 8% of both Lippia and Ocimum combined, compared to 91.4% of Azadirachtin. Gall numbers reduced by 98.3% in roots compared to 98.7% recorded in Azadirachtin. Total root volume of 308.7 cm3 was recorded in 8% LK + 8% OG compared to 69.33 cm3 and 89 cm3 for non-amended and Azadirachtin treatments, respectively. Means on leaf numbers were 29.90 compared to 22.67 and 28.13 of non-amended and Azadirachtin, respectively. Shoot and root dry weights of 53.17 g and 100.85 g were recorded compared to 24.17 g and 46.12 g and 51.75 g and 86.23 g for non-amendment and Azadirachtin, respectively. The yields were 2.71 kg per plant at 8% LK + 4% OG compared to 0.53 kg of non-amended treatment. Thus, L. kituensis and O. gratissimum L. are potential nematicides and can be used in tomato nutrition for sustainable production in the greenhouse.