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Screening best practices

WorldVeg field trials are the testing ground for safe vegetable production technologies in Tanzania.

Ms. Anna Roman, Extension Officer at Matufa, shows a farmer how to spot Tuta absoluta damage.

Ms. Anna Roman, Extension Officer at Matufa, shows a farmer how to spot Tuta absoluta damage.

As part of the Africa RISING project, the World Vegetable Center promotes safe vegetable production practices among farmers and extension agents in Tanzania. In village-based field trials, the WorldVeg team demonstrates the use of simple screenhouse structures and biopesticides to control whitefly (Bemisia tabaci) and Tuta absoluta on tomatoes and peppers.

Research Assistant Inviolate Dominick monitored crop production experiment trials from 29 May to 1 June 2019 in Bermi, Matufa and Shaurimoyo villages in Babati District, and offered guidance on data collection to extension agents and farmers managing the trials. Tomato and sweet pepper plants in trial plots were assessed for plant growth and development, occurrence of pests and diseases, and overall status.

In all locations, the plants grown inside screenhouse structures were larger and more vigorous than the crops grown in the open field, developing more flower clusters and fruit. Although whitefly and Tuta still found a way to get inside the screenhouses, the infestations inside were much milder than those in the open field. Traps installed inside the screenhouses and out in the fields help project participants identify pests and monitor pest populations.

Inviolate demonstrated pruning and staking methods, which allow for better airflow in the screenhouse and help prevent diseases such as powdery mildew. “WorldVeg is committed to continue strengthening farmers’ skills in Good Agricultural Practices, pest identification and management, and data handling,” she said.

Training Coordinator Hassan Mndiga traveled to Bermi, Matufa, and Shaurimoyo from 24-27 June 2019 as the trials began to bear fruit. Although some evidence of spider mites and early and late blight was observed, along with blossom end rot (the result of uneven water supply), overall performance of both crops inside the screenhouses was very good. In Shaurimoyo, seedlings treated with a biopesticide (Metarhizium) were comparatively less affected by wilt.

With proper management, physical barriers such as screen or net houses to prevent pest access to crops and the use of safe biopesticides can reduce the need for chemical controls. Hassan encouraged the extension agents working on the project to assist farmers in pest and disease scouting. “This information is vital for managing crop health in the experimental trials,” he said.

Story and photos: Inviolate Dominick and Hassan Mndiga

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Collecting data from the trial plots.

Dr. Simon Boniface and Christopher Paul investigate insect pest damage in tomato.

Dr. Simon Boniface and Christopher Paul investigate insect pest damage in tomato.

POWER ON YOUR PLATE: An All-Africa Summit on Diversifying Food Systems with African Traditional Vegetables to Increase Health, Nutrition and Wealth

25-28 May 2020
Arusha, Tanzania


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