Effect of mulch and different fungicide spray regimes on yield of tomato (Solanum Lycopersicum L.) in Tanzania

In many areas in Tanzania, pests management for tomato involves weekly pesticide sprays. The practice poses a threat to the environment and health of consumers. In this study the effect of pesticide spray regimes and use of mulch were evaluated on ‘Tanya VF’ and ‘Tengeru 97’ tomato varieties. Field experiment consisting of a 2×2×4 factorial arrangement in a split-split plot design with three replications was conducted at Sokoine University of Agriculture, Morogoro (6o05’S, 35o37’E and 525m above sea level). Treatment factors comprised two varieties (main plot factor), mulching/number of mulching (subplot factor) and three fungicide spray regimes (sub subplot factor). Results showed that the spray regimes: farmers’ practice (FP), Integrated Pests Management (IPM) based on pests scouting, sprays based on manufacturers’ recommendation (MR); produced significantly more fruits per plant and higher fruit weight compared to the control. There was no significant difference (p < 0.05) between FP, IPM and MR on fruit yield parameters. The results further revealed that use of mulch significantly led to higher fruit number per plant (p = 0.020). Although average fruit weight was similar (p < 0.05), other marketable fruit yield parameters were statistically different between mulched and non-mulched plots (p = 0.007). ‘Tanya VF’ had consistently higher yields compared to ‘Tengeru 97’. Fungicide sprays were statistically different to the control with respect to blossom end rot (p = 0.002), fruit rot (p < 0.001) and percentage of non-marketable yield (p = 0.001). Mulching significantly reduced American bollworm and blossom end rot (p = 0.012, p = 0.003, respectively). The major contributor to tomato fruit loss was Blossom End Rot (BER) and Fruit Rot for ‘Tengeru 97’ and ‘Tanya VF’, respectively. It is evident, therefore, that: a proper combination of tomato cultural management practices can significantly reduce the use of pesticides, and improve tomato fruit quality and marketable yield which would increase profit margin accrued by farmers