Sustainable Solutions for Vegetable Diseases: Research and Development Activities in Indonesia Gregory C. Luther, Joko Mariyono, Putu Sudiarta, Made S. Utama, Alit Susanta Wirya, Rakhmat Sutarya, Kuntoro Boga Andri, Ketut Kariada, Evy Latifah, Eli Korlina, Ketut Sumiartha, Arief L. Hakim, Engkus Kuswara, Donald Tambunan, Victor Afari-Sefa, Wallace Chen, Jaw-Fen Wang, Li-Ju Lin Introduction: A four-year project was conducted in Indonesia with various vegetable disease management research and development activities, focusing on grafting, neutralized phosphorus salt (NPS), rain shelters, the bio-agent Trichoderma harzianum, and host-plant resistance. This project was funded by USAID. Objective: To investigate and disseminate sustainable solutions for tomato and chili pepper diseases. In a lowland field trial in East Java, AVRDC – The World Vegetable Center’s eggplant rootstocks effectively protected grafted tomato scions from bacterial wilt. While grafted tomato plants survived until harvest to produce yield, non-grafted plants died before fruiting. In a highland field trial in Bali, NPS (a kind of biopesticide) controlled tomato late blight as effectively as chemical fungicides currently used by farmers. NPS costs less (and therefore has higher net returns) and has low toxicity to humans and the environment. A field trial in Bali integrating grafting, NPS, rain shelters and Trichoderma harzianum was effective at reducing disease incidence on tomato; control plants had a significantly higher disease incidence rate and those with all four technologies showed the lowest level of disease incidence and severity. An off-season tomato trial in East Java showed that rain shelters reduce the intensity of disease incidence and NPS reduces the severity of late blight. The combination of NPS and rain shelters showed greater effective protection against diseases in the rainy season. Improved tomato and chili lines were tested for disease resistance: Farmer Field Schools (FFS) were conducted to train 3,280 farmers (35% women) on various tomato and chili production technologies drawn from the project’s adaptive research results. The project team produced extension publications in Indonesian on grafting and NPS. Outcomes and Conclusions: Grafting is being adopted by farmers and nursery operators; approximately 100 farmers in Bali planted grafted tomato in An independently-conducted outcome assessment indicated that knowledge transfer through FFS was effective. Materials and knowledge disseminated through the FFS were perceived by farmers to be useful, and have been implemented, at least partially, by a majority of FFS participants. FFS had a positive impact on the crop yield produced by FFS farmers compared to their counterfactual. Methods and Results: NPS Chemical fungicides Chili pepper linesDisease resistance or tolerance AVPP1102-B, AVPP0513, AVPP0719, AVPP0207, AVPP1004-BHigh fruit yield and tolerance to anthracnose AVPP0207, KencanaResistance to geminivirus and anthracnose, but fruit type does not match local preference AVPP1003–B and AVPP1004–BResistance to geminivirus Tomato linesDisease resistance or tolerance AVTO1139, Ratna, Hawaii 7996, Permata, AVTO0301, AVTO1109, AVTO1010, AVTO1122, AVTO1133 Resistance to bacterial wilt AVTO0922, AVTO1139, AVTO1010, AVTO1173, AVTO1173Resistance to geminivirus