Hiratsuka, Japan—The Yokohama Rubber Co., Ltd., announces that results of an international joint research project for “Development of Complex Technologies for Prevention and Control of Rubber Tree Leaf Fall Diseases” (hereinafter, “this research project” or “the project”) were presented on August 1 in a public lecture by lead researcher Minami Matsui (Project Professor at Yokohama City University and Senior Visiting Scientist at RIKEN) on “The History of Rubber Trees Around the World and Collaborative International Measures Against Tree Leaf Fall Disease (LFD).”

Yokohama Rubber has been participating in this research project as a cooperating corporation. The project, which aims to achieve sustainable production and use of natural rubber by preventing and controlling rubber tree diseases, has been selected as a research project in the Science and Technology Research Partnership for Sustainable Development (SATREPS) program, which is jointly implemented by the Japan Science and Technology Agency (JST), the Japan International Cooperation Agency (JICA), with support from Japan’s Ministry of Foreign Affairs and the Ministry of Education, Culture, Sports, Science and Technology. This research project is an international project being conducted jointly by industry, government, and academic institutions in Japan, including RIKEN, and in Indonesia, the world's second largest producer of natural rubber. The spread of LFD in Indonesia has severely reduced the country’s production of rubber. This research project aims to stabilize production by smallholders, which account for more than 90% of Indonesia’s natural rubber production, by using pesticides to exterminate LFD.

Since the project’s launch in 2020, screening and selection of pesticides has been followed by field evaluations at a rubber research institute’s test farm and corporate plantations, leading to field evaluations at small farms, the target of this research, from September 2025. At each phase, Yokohama Rubber has contributed to quality control by investigating the presence or absence of pesticides in natural rubber latex and their effects on the properties of natural rubber and vulcanized rubber, thereby confirming that the proper application and use of those pesticides do not affect rubber’s quality. All planned field evaluations have demonstrated the effectiveness of the selected pesticides, and the project is now planning to move fully into a practical phase that will include the registration of pesticides to be used in Indonesia.

Yokohama Rubber’s “Procurement Policy for Sustainable Natural Rubber" includes providing support for those involved in the supply chain, including small-scale farmers. The Company believes participation in this research project will contribute to the sustainable production of natural rubber and more stable incomes for natural rubber farmers. Yokohama Rubber also is participating as an official partner institution on SATREPS research project for “Utilization Technology of Rubber Seeds for Green Products to Mitigate Global Warming and Plastic Pollution,” which aims to solve environmental problems through the effective use of natural rubber seeds.

Under the sustainability slogan “Caring for the Future,” Yokohama Rubber is creating shared value by addressing social issues through its business activities.

Title
Development of Complex Technologies for Prevention and Control of Rubber Tree Leaf Fall Diseases

Principal Investigators
Minami Matsui (Yokohama City University Kihara Institute for Biological Research, Project Professor/RIKEN Center for Sustainable Resource Science, Senior Visiting Scientist)
Suroso Rahutomo (Indonesian Rubber Research Institute, Director)

Research Topics & Activities
1. Development of a candidate chemical for pesticides against rubber tree leaf fall diseases
2. Development of a novel microbial biofungicide for rubber tree leaf fall disease
3. Creation of clones resistant to rubber tree leaf fall diseases
4. Development of a system using satellite and drone data to detect areas infected by rubber tree leaf fall diseases
5. Research on next-generation technology for prevention and control of rubber tree leaf fall diseases in Indonesia and establishment of social infrastructure for their control

Joint Research Partner Countries / Major Research Institutions
Indonesia / Indonesian Rubber Research Institute, Universitas Indonesia
Japan / RIKEN Center for Sustainable Resource Science, Gifu University, RIKEN Center for Advanced Photonics (RAP), Maebashi Institute of Technology, Yokohama City University