Pesticide registration is a crucial link in ensuring the quality and safety of agricultural products, ecological and environmental safety, and human health. However, "long registration cycle and high investment cost" are common challenges faced by many pesticide enterprises. Once a registration application is not approved, all previous investment costs of the enterprise, such as R&D and testing, will be wasted, and the precious time cost is even more irrecoverable. Therefore, it is particularly important for enterprises to conduct sufficient research in the early stage of registration and accurately grasp the product safety, effectiveness and relevant registration policy requirements. Combining industry regulatory practices, this article sorts out some scenarios where pesticide product registrations are no longer approved by relevant authorities, providing references for enterprise registration planning and helping enterprises avoid registration risks.

I. Eight Scenarios Where Mixed Formulation Registration is Principally Not Approved

Mixed formulations have become a research and development direction for many enterprises due to their potential advantages such as expanding the control spectrum, improving control efficiency, and delaying resistance. However, not all mixed formulations can pass the registration review. The following eight scenarios are principally not approved for mixed formulation registration (including registration for expanded scope of use):

1. Antagonistic joint action on target pests: If the active ingredients in the mixed formulation exhibit antagonistic effects on the target pests, that is, the control effect after combined use is lower than that of a single ingredient, such mixed formulations lack the necessity for registration and are principally not approved.

2. No synergistic effect for agricultural and forestry insecticides: For mixed insecticide formulations used in agricultural and forestry fields, if tests prove that no synergistic effect is achieved after mixing, and only the effect of a single agent is achieved or there is no significant improvement in effect, the registration will not be approved.

3. Mixing of active ingredients with the same mechanism of action (except for special cases): Mixing of active ingredients with the same mechanism of action tends to accelerate the development of pest resistance and is generally not approved. However, if authoritative tests or sufficient data prove that the mixed formulation has low cross-resistance risk and clear necessity and rationality for mixing, it may be considered as an exception.

4. Specific cross-category mixing and mixing solely for expanding the control spectrum (except for seed treatment agents): The mixing of insecticides with fungicides, and the mixing of insecticides or fungicides solely for expanding the control spectrum, except for seed treatment agents, are principally not approved for registration. Such mixing does not meet registration requirements if it lacks core advantages such as clear synergistic effect and only aims to expand the control scope.

5. Mixing of plant growth regulators with other types of pesticides: Mixed formulations of plant growth regulators with insecticides, fungicides, and herbicides are not approved for registration due to large differences in their mechanisms of action and high risks of phytotoxicity or uncontrollable effects.

6. Mixing of chemical pesticides with botanical pesticides: Chemical pesticides and botanical pesticides have significant differences in their mechanisms of action and metabolic pathways. Mixed formulations may have problems such as poor stability and large fluctuations in effect, and are principally not approved for registration.

7. Specific herbicide mixing (except for those filed before October 26, 2022): Mixed formulations of non-selective herbicides such as glyphosate with selective herbicides for farmland are no longer approved for registration, except for products that completed filing before October 26, 2022.

8. Specific registration scenario for fludioxonil mixtures: Registration of fludioxonil mixtures applied solely to cotton damping-off is principally not approved.

II. Key Considerations for Registration of Other Formulation Products

In addition to mixed formulations, there are also some easily overlooked key points for single formulations and specific types of pesticide products during the registration process. Enterprises need to focus on these points to avoid registration failure due to trivial issues:

1. Registration restrictions for tricyclazole: Tricyclazole has low activity and poor actual control effect against Rhizoctonia solani (the pathogen causing rice sheath blight) and Ustilaginoidea virens (the pathogen causing rice false smut). Currently, registration of tricyclazole for the control of rice sheath blight and rice false smut is no longer approved. Enterprises should avoid submitting registration applications for these control targets.

2. Adaptability of imidacloprid to control targets: Imidacloprid has low activity and poor control effect against lepidopteran pests. When planning the registration of imidacloprid products, enterprises need to fully evaluate the adaptability of the control targets and avoid selecting lepidopteran pests as the main control targets.

3. Caution for special application scenarios of mancozeb: As a commonly used fungicide, the mechanism of action of mancozeb for controlling citrus rust mites has not been clarified, and its effect and safety lack sufficient scientific basis. Enterprises need to be particularly cautious when registering for this application scenario and conduct sufficient test verification in advance.

4. Compatibility between formulation and application method for public health pesticides: There are strict corresponding requirements between the formulation and application method of public health pesticides, which must be strictly followed: products with formulations of soluble concentrates and emulsion in water generally cannot use residual spraying; products with formulations of wettable powders and microcapsule suspensions are prohibited from being used for indoor space spraying.

5. Application scenario restrictions for lambda-cyhalothrin: Lambda-cyhalothrin formulations with moderate toxicity are prohibited from being used in indoor environments. Enterprises need to strictly avoid indoor scenarios when planning their scope of use.

6. Control target restrictions for pyriproxyfen: Registration of pyriproxyfen for the control of adult flies (mosquitoes) is no longer approved. Enterprises need to adjust the control target planning of this product and avoid submitting registration applications for this scenario.

III. Core Response Strategies for Enterprises in the Early Stage of Registration

Facing the strict review requirements for pesticide registration, enterprises need to prioritize risk avoidance and do a good job in three core aspects in the early stage of registration: First, strengthen the research on core product performance, fully grasp the mechanism of action, action characteristics of active ingredients and their compatibility with other ingredients, and verify the safety and effectiveness of products through preliminary tests to avoid blind R&D. Second, accurately align with registration policy requirements, pay close attention to industry regulatory trends, sort out the registration restriction scenarios of various products, and ensure that the R&D direction meets the review standards. Third, focus on the accurate positioning of control effects, conduct sufficient field tests for target pests, clarify the advantages of product control effects, and provide solid data support for registration applications.

The rigor of pesticide registration is an important prerequisite for ensuring agricultural production safety. Only by adhering to the concept of scientific R&D and avoiding registration risks in advance can enterprises improve the success rate of registration, reduce investment costs, and achieve high-quality development.