In 1967, an accidental discovery of "Carbendazim" at DuPont's American lab opened a new chapter in pesticide application. Four years later, Japanese scientists, through structural modification, developed "Thiophanate-methyl" with enhanced penetrative power. These two chemically similar "siblings" quickly became key weapons in combating fungal diseases in crops worldwide over the next five decades. However, alongside their widespread use, concerns about potential carcinogenic residues led to continuous scrutiny and restrictions.

An international uproar surrounding Carbendazim, dubbed the "Brazil Orange Juice Controversy," erupted in 2011. After 13 years of intense debate, Brazil's Chamber of Deputies Agriculture Committee approved a legislative decree in November 2024. The decree highlighted Carbendazim's widespread use in over 80 countries and argued for a lack of global scientific consensus to justify its prohibition. It also affirmed Carbendazim's importance in controlling diseases in crops like beans and rice, thereby overturning the previous ban by Brazil's National Health Surveillance Agency (Anvisa). This temporarily settled the "orange juice controversy," a microcosm of humanity's ongoing dilemma between "ensuring yield" and "guaranteeing safety."

Carbendazim: The Glory and Challenges of a Veteran Fungicide

Carbendazim, known for its high efficiency, low toxicity, and broad spectrum, is widely used on various crops such as rice, wheat, fruit trees, and vegetables. It was initially developed by DuPont, registered in 1967, and industrialized and globally promoted by 1970. In China, Carbendazim showed significant efficacy in controlling wheat scab in 1972, solidifying its status as a "national fungicide."

However, its health risks gradually came to light. The United States revoked its registration for use on food products starting in 2007, and the International Agency for Research on Cancer (IARC) classified it as a Group 2B "possibly carcinogenic" agent. China's agricultural sector also issued warnings in 2016, allowing its use but emphasizing controlled risks and planning to update residue limits. Despite these controversies, global demand for Carbendazim technical is projected to reach 30,000 tons annually by 2025, with China being a major producer and exporter.

Thiophanate-methyl: Carbendazim's "Upgraded Armor"

Compared to Carbendazim, Thiophanate-methyl, due to the introduction of a "sulfur" element, possesses stronger systemic properties. It transforms into Carbendazim within the plant, enabling more "precise targeting" of pathogens, particularly effective for delicate fruits, vegetables, and flowers. It was successfully developed by Nippon Soda Co., Ltd. in 1969 and widely adopted in China during the 1970s.

Nevertheless, Thiophanate-methyl also faces challenges. The European Union in 2020 did not approve its re-evaluation application and has been phasing out its use. Global demand for Thiophanate-methyl technical is estimated to be around 25,000-30,000 tons annually by 2025, with China being a leading producer and consumer.

Prolonged use of both Carbendazim and Thiophanate-methyl can lead to pathogen resistance, and residue concerns raise food safety and environmental health issues. In recent years, market shares have fluctuated due to increased resistance, stricter environmental policies, and competition from new fungicides.

Formulation Market and Future Outlook

Carbendazim and Thiophanate-methyl, as highly efficient, low-toxic systemic broad-spectrum fungicides, are widely used not only in agriculture but also in industrial anti-mildew and anti-corrosion applications, for example, as additives in coatings. In agriculture, they are formulated into various forms such as wettable powders and suspension concentrates, and often used in compound products to control diseases like root rot and anthracnose in fruit trees, powdery mildew and downy mildew in vegetables, and scab and sheath blight in field crops, even for post-harvest fruit preservation.

Despite numerous challenges, these "twin champions" continue to sustain their vitality through combination with novel fungicides (e.g., Thiophanate-methyl + Pyraclostrobin for apple ring rot). In the future, their development may shift towards regional precise applications, with Carbendazim focusing on soil treatment for field crops, and Thiophanate-methyl targeting high-value fruit and vegetable diseases and post-harvest preservation. Their future battleground is moving from laboratories and farmlands to legislative hearings and consumer perception, but they are still expected to remain enduring products in the plant protection market.