[Setsunan University] Elucidation of Causes of Fruit Rot in Processing Tomatoes During Maturation

A joint research group led by Associate Professor Yuichiro Iida of the Department of Agricultural Production, Faculty of Agriculture at Setsunan University (President: Yasuyuki Kubo), and the major food manufacturer Kagome Co., Ltd., has elucidated the causes of fruit rot symptoms observed in processing tomatoes during the maturation stage. These research findings are expected to serve as fundamental knowledge for developing disease control measures.

Processing tomatoes, used as raw materials for products like juice, require stable quality and large-scale production. In recent years, the introduction of mechanized harvesting systems has progressed in processing tomato cultivation, driven by the aging of producers and the goal of stable production. Because mechanical harvesting involves harvesting all fruits at once, uniform ripening (a trait where multiple fruits turn red simultaneously) is required. However, enhancing uniform ripening can lead to a rapid progression of rot symptoms caused by diseases during the maturation stage. Such rot leads to reduced productivity and lower yields, posing a long-standing challenge for producers. Furthermore, the detailed mechanisms, such as which specific diseases cause these rot symptoms, had not been sufficiently clarified until now.

Therefore, Associate Professor Iida's research group isolated microorganisms from the rotten parts of processing tomato fruits collected from domestic fields and conducted an analysis. The results revealed that multiple filamentous fungi, specifically of the genera Colletotrichum and Alternaria, are involved in the rot symptoms, with symptoms appearing particularly strongly in mature fruits. They discovered that multiple species within the Colletotrichum genus are involved and confirmed the reproduction of characteristic symptoms observed in cultivation fields.

Moving forward, it is expected that these fundamental findings will contribute to sustainable agricultural production through the development of disease-resistant varieties for stable processing tomato production and the establishment of new control technologies to prevent yield loss.

These research results were published in the international academic journal in the field of plant pathology, "European Journal of Plant Pathology," on February 3, 2026.

URL: https://doi.org/10.1007/s10658-026-03190-w

DOI: 10.1007/s10658-026-03190-w