By Jigyasa Pareek

Section 3(h) of the Patents Act, 1970, excludes from patentability “a method of agriculture or horticulture”. This provision was introduced on the recommendations of the Justice Ayyangar Committee Report (1959), which recommended that inventions relating to plant propagation by asexual methods be excluded from patent protection. But the question that has gained prominence in recent years is: does Section 3(h) extend to a scientific method for treating plants, such as pest or disease control?

Before the 2002 amendment to the Patents Act, Section 3(i) expressly barred patents for “any process for the medicinal, surgical, curative, prophylactic, diagnostic, therapeutic or other treatment of human beings or animals or plants”. Following the amendment, the reference to “plants” was omitted. The legislative intent was clear: while methods of treating a human being or an animal remain excluded, methods of treatment of plants were removed from the list of non-patentable subject matter.

The purpose of Section 3(h) was to preserve farmers’ rights to practice traditional agricultural methods without the risk of infringing patents. However, with modern agricultural biotechnology introducing innovative, non-traditional plant-treatment methods, the scope of this exclusion has become contested. Patent examiners often treat plant-treatment methods as “agricultural methods”.

Over the last few years, the Courts have attempted to delineate the boundary between a conventional agricultural process and a scientific method of treating plants.

• In Decco Worldwide Post Harvest Holdings B.V. & Anr. vs Controller of Patents & Designs & Anr.[AID No. 11/2021, decision dated May 19, 2023], the Calcutta High Court held that the Controller failed to explain how a method for treating fungal diseases in plants could be considered an agricultural method. It observed that Section 3(h) covers traditional methods of agriculture.
• In Mitsui Chemicals Inc vs Controller of Patents [C.A.(COMM.IPD-PAT) 196/2022, decision dated February 23, 2024], the Delhi High emphasized that a detailed and reasoned analysis is mandatory when invoking Section 3(h). It observed that it is crucial to distinguish between solely ‘agricultural’ methods and those based on ‘technical or scientific foundation addressing agricultural problems’.
• In Syngenta Crop Protection AG vs Assistant Controller of Patents[C.A.(COMM.IPD-PAT) 63/2024, decision dated November 26, 2024] the Court remarked that a method for the treatment of plants does not fall within the list of exclusions provided in the Manual of Patent Office Practice and Procedure 2019 regarding patentability under Section 3(h). The Manual lists certain agricultural practices, such as methods for producing plants, improved soil, mushrooms, cultivating algae, and removing weeds, as non-patentable methods under Section 3(h), but it does not include methods for treating plant diseases.

The Delhi High Court’s recent decision in Valent Biosciences LLC vs Controller of Patents and Designs [C.A.(COMM.IPD-PAT) 25/2022, decision dated September 26, 2025] sits squarely within that developing stream. The appeal concerned Patent Application No. 2904/DELNP/2011, titled “Synergistic Bacillus Thuringiensis Subsp. Kurstaki and Chlorantraniliprole Mixtures for Plant Pest Control.” The invention claimed a synergistic method of pest control, involving the application of Bacillus thuringiensis subsp. kurstaki and chlorantraniliprole within a specific ratio (1:0.001 to 1:0.08) to control five Lepidopteran pests: Diamondback moth, Beet armyworm, Sugarcane borer, Soybean looper, and Corn earworm.

The application was refused on the grounds of lack of inventive step and non-patentability under Section 3(h) of the Patents Act, 1970.

The Patent Office had held that because the method involved “applying” a formulation to crops in the field, it was a “method of agriculture or horticulture” within the meaning of Section 3(h). The Controller’s reasoning was that since the pest control was performed (in the form of wettable powder formulations/water dispersible granules/granules, and emulsifiable suspension concentrates) on standing crop plants in agricultural fields by applying the composition of Bacillus thuringiensis subsp. kurstaki and chlorantraniliprole, it automatically fell within the exclusion. No further explanation was offered as to how the claimed process resembled “conventional” agriculture.

The Court found both objections unsustainable.

On Inventive Step

The Court determined that none of the cited prior art documents disclosed both active agents and the specific target pests together. The Controller’s reasoning was conclusory and lacked explanation as to how a person skilled in the art would combine these teachings to reach the claimed method.

On Section 3(h)

The Court cited the relevant paragraph (Page 152) from the Ayyangar Committee Report which clarified that the intention behind the provision was to deny patents for “inventions in the field of plant propagation by asexual methods”. The Court also turned to the Guidelines for Examination of Biotechnology Application for Patent, 2013 (Page 237), which expressly state that “conventional methods performed on actual open fields should be construed as methods of agriculture/horticulture”.

The Court underscored that the treatment of human beings or animals is already barred under Section 3(i), and that exclusion does not extend to plants.

The Court found the Patent Office’s reasoning fatally inadequate. Simply noting that the formulation is applied to plants in the field does not establish that the process is a method of agriculture. The Controller failed to:

• identify how the claimed process would fall under the purview of Section 3(h) of the Act, which covers traditional methods of agriculture;
• distinguish between solely ‘agricultural’ methods and those based on ‘technical or scientific foundation addressing agricultural problems’; and

In view of the foregoing, the Court set aside the impugned order and remanded the subject application for a de novo consideration.