Growing Tomato (Lycopersicon esculentum L.) in Nematode Infested Soil and the Pest Implications in Poorly Managed Post-harvested Fields During the Dry Season in Tanzania

Abstract

Tomato (Lycopersicon esculentum L.) is an important income generating crop in the semi-arid areas in the Miombo ecosystem in Tabora, Tanzania. Dry season tomato growing is limited by water resource availability and it is therefore cultivated continuously in the same areas with access to water for irrigating the crop. Parasitic root-knot nematodes are a threat to tomato production. In this study, the effect of Procarvian carpensis manure at a rate of 5tons/ha and the balanced NPK inorganic fertilizer at a rate of 100kg/ha on the growth performance of the tomato genotype “Duluti” on a highly root-knot nematode soil was evaluated. The field experiment was laid in a randomized complete block with three replications. More studies were carried out in farmers’ fields to assess the influence of poor management of post-harvested tomato fields as host to crop pest. In the field experiment tomato plants’ vegetative and reproductive parameter data were  collected. They were then subjected to analysis of variance using the GENSTAT 14th Edition at a difference declared significance of 5% level. Least significance difference (LSD) was used in means separation. Results show that, the average of 9 fruits/plant harvested in the plots applied with of 5tones/ha of P. carpensis manure is highly significantly (p<0.001) her than 4 fruits per plants in plot with NPK YaraMira cereal. This may reveal that P. carpensis manure improved the growth performance of tomato and increased its tolerance to parasitic nematodes. Substantial infestation of the tomato plants by root-knot nematode grown in the control plots may be the reasons for their failure to flower. Results from the field survey show that red spider mites (Tetranychus evansi: Acaricidae) and mealbugs (Phenacocus manihot: Cydnidae: Hemiptera) and downy mildew were surviving the dry season using tomato plant residues and associated weed species. Tomato production using organic P. carpensis and field sanitation after harvesting may assist in substantial reduction of the root-knot nematode and other crop pest incidences. Furthermore studies involving several rates and sources of organic and inorganic fertilizers and tomato varieties should be conducted in areas with high nematode infestation to come up with better genotype and fertilizer type and combination thatwill reduce nematode incidences and at the same time improve tomato yield.

Key words: Dry season, root-knot nematodes, post-harvest sanitation, tomato; and Tanzania.