Global overview of herbicides in paddy fields and introduction of new products Agrochemicals

Global Overview of herbicide use in paddy fields

It is reported that the market sales of pesticide in global paddy fields increased by 7.8% in 2018 to $5.972 billion, accounting for 10.4% of the total pesticide market share, making it the fifth largest crop after fruits and vegetables, cereals, soybeans and maize. Although the planting area is relatively same, increased consumption and higher product price contributed to the increase in pesticide sales. Over the past five years, pesticide sales in paddy fields have grown rapidly at an average annual rate of 2.7%. The paddy herbicide market accounted for 40.3% of the total pesticide sales, followed by insecticides at 32.4% and fungicides at 25.4%.

The top three herbicide sales in the global paddy field were Cyhalofop-butyl, Glyphosate and Penoxsulam.

Japan's paddy herbicide market grew 1.4% to $605 million in 2018 due to the depreciation of the yen and higher product price, despite a 0.4 % decrease in planted area. The herbicide market in China grew 10.0% in sales to $486 million in 2018. In China, the paddy weeds mainly included Echinochloa crusgalli, Scirpus, Eleocharis parvula, Monochoria korsakowii. Herbicide products included Swep, Butachlor, Glufosinate-ammonium and Glyphosate. At present, the resistance of paddy weeds is increasing in China. Herbicide use in India is relatively low, the herbicide market grew 10.4% to US $212 million in 2018. The top ten herbicides used in paddy fields and their markets are shown in the following Table.

New herbicide products developed recently in paddy fields

Tetflupyrolimet

Tetflupyrolimet was developed by DuPont (now Corteva) and has a novel mechanism of action. In 2018, DuPont transferred its patent to FMC. It can inhibit the growth of weeds by inhibiting the synthesis of Pyrimidine, which is a key molecule in weeds. It can effectively control the important weeds, broad-leaved weeds and sedges in paddy fields during the whole season, and it can be used for transplanting paddy. Tetflupyrolimet is a patented product of FMC. In 2021, it was classified into a new mechanism of action classification, becoming the first active ingredient in HRAC and WSSA of herbicide Group28. It is expected to be launched in 2024.

Bixlozone

Bixlozone, an Clomazone-based herbicide developed by FMC, was registered in Australia in April 2020 and is expected to be available in winter 2021.

Bixlozone has a new and unique selectivity and a long residual effect period. It inhibits the synthesis of carotenoids and chlorophyll in weeds, resulting in leaf whitening and plant death. Crops will metabolize bixlozone and continue to grow. Bixlozone can be used early in the pre-shoot, post-shoot period, or during seeding to expand the weed control spectrum with reduced usage. Bixlozone is safe for a variety of crop rotations, making it an ideal mix partner for broadleaf herbicides. Bixlozone can be used on a wide range of crops, including cereals, maize, legumes, canola, paddy and sugarcane.

Cyclopyranil

Cyclopyranil is a Pyrazole-based herbicide developed by Kyoyu. It has a control effect on Monochoria vaginalis, Barnyard grass, Crab grass and Amaranthus viridis.It also has a good control effect on weeds in dry field crops. This compound was first discovered by Schering (now Bayer), which developed Pyraclonil in 1994.

Lancotrione

Lancotrione, a trikeone HPPD inhibitor herbicide developed by ISK, was released in 2019 and commercialized in the form of sodium salts. At the effective dose, it is safe for paddy, and has good control effect on Echinochloacrusgalli, Scirpus and Arrowhead.

Florpyrauxifen

Florpyrauxifen is a synthetic hormone herbicide developed by Dow (now Corteva), which was officially registered in China in August 2017. The generic name is Florpyrauxifen-benzyl. Florpyrauxifen is the first product of a new chemical class of arylpicolinate in the synthesis of auxin herbicides. It has high efficiency, broad spectrum weeding activity, can control grass weeds, sedges and broadleaf weeds, suitable for paddy, wheat and other crops. On Oct 6, 2017, the US Environmental Protection Agency issued Regulation 82 FR46685 to amend the maximum residue limits for Florpyrauxifen in paddy and fish. The revised residue limit for Florpyrauxifen is 0.3mg/L for paddy; Fresh freshwater finfish 2.0mg/L; Fish and shellfish crustaceans 0.5mg/L; Fish shell molluscs 20mg/L.

Tripyrasulfone

Tripyrasulfone is a new type of HPPD inhibitor herbicide developed by KingAgroot, which was launched in the spring of 2020. It can disrupt carotenoid biosynthesis and cause chlorophyll to lose protection, which affects photosynthesis and causes weed death. The mechanism of action is complex, so it is difficult for weeds to develop resistance. Tripyrasulfone has played an important role in the control of grass weeds in paddy fields, especially in the control of resistant barnyard grass and moleplant seed.

Metcamifen

Metcamifen is a herbicide safety agent developed by Syngenta. The compound belongs to direct synthesis with Sulfanilamide as the intermediate raw material. Metcamifen can stimulate the production of Glutathione S-transferase (GST), which can catalyze the binding of reduced Glutathione to pesticide residues, to achieve the purpose of detoxification. It is suitable for cereals, soybeans, sorghum, maize and paddy. In June 2020, APVMA proposed approval of a new product from Syngenta, Epivio C Sorghum Seed Herbicide Safety Agent containing Metcamifen (Metcamifen 400g/L).

Dimesulfazet

Dimesulfazet, an herbicide discovered and developed by Matsumoto, is expected to be available in Japan in 2024. At present, this compound has not been classified by HRAC. Because it belongs to the Sulfonyanilide herbicide, it is estimated that its action mechanism may be the same as other similar structural herbicides, and it belongs to the ultra-long chain fatty acid synthesis (VLCFAE) inhibitor. It is used to control sedge in paddy field and has good control effect on resistant weeds.

Fenquinotrione

Fenquinotrione is a novel Triketone herbicide developed by Kumiai., which was launched in 2018 to control broadleaf, grass and sedge in paddy production. Fenquinotrione is highly selective against paddy and barnyard grass.