Efficacy of neem and netting in management of Tomato leafminer, Tuta Absoluta (Meyrick) (Lepidoptera: Gelechiidae) on tomato productivity among smallholder producers as compared to synthetic insecticides use in Morogoro, Tanzania

Muhoja became associated with ProGrOv when he became enrolled as a MSc student at University of Copenhagen under the Building Stronger University programme. Under the supervision of Lene Sigsggard, responsible for the pest management sub-project of ProGrOV, he did his field work in Tanzania in connection with other of the ProGrOV studies at SUA and with support from the ProGrOV supervisor professor K. Sibuga.

With the focus on tomato the objective of his study was to provide a contribution to the understanding of the pest problem caused by T. absoluta, farmer’s decision to management and test insecticides use alternatives to minimise losses caused by the pest and other pests of tomatoes amongst smallholder farmers in Morogoro.

Tomato is an important vegetable crop grown worldwide. In Tanzania, it is grown by small and medium scale farmers as a source of income and consumption. Tanzanian Tomato production reported dropping by 50% due to several factors mainly pests and diseases. The devastating pest threatening tomato production is the South American native tomato leaf miner, Tuta Absoluta (Meyrick) (Lepidoptera: Gelechiidae).

The study involved two parts, interviews and surveys on tomato production practices and a field experiment testing the efficacy of the management practices on tomato productivity. It involved 75 questionnaires from 25 responded in each of the three study areas Doma, Wami-Dakawa and Kipera respectively. The field experiment was a randomised complete block design (RCBD) with four treatments, neem extract, netting, an insecticide flubendiamine 480g/l and a no treatment control with five replications. The experiment included two sites(Kipera and Wami-Dakawa.

The results showed that farmers understand T. absoluta as a problem to tomato production and use insecticides to manage the pest with less understanding on the proper insecticide to use. Results from the field experiment showed that the insecticides use alternatives (neem, and netting) treatment significantly increased yield in comparison to the control. There were no significantly different between the alternatives to the insecticides flubendiamine 480 g/l suggesting that the alternative can be included in the IPM program to manage the pest as they have the less side effect to health and environment as compared to an insecticide. Regarding pest population, the treatments significantly reduced the population of T. absoluta, noctuid, whiteflies and aphids compared to the control. Although, the netting was not effective in the control of spider mites. The spider mites population was high in the netting and not significantly different to the control. Further investigation should be performed by integrating other methods to reduce the population of spidermites in the netting.