Simulation and application assessment of the efficacy of fosthiazate‐loaded microcapsules against root‐knot nematode

• Published in: Pest management science 2024-10, Vol.80 (10), p.5078-5087
• Main Authors: Maruyama, Takahiro, Ishibashi, Yutaka, Sano, Mitsuo, Yoshimura, Hideshi, Taguchi, Yoshinari
• Format: Article
• Language: English
• Subjects: Biological effects; Biological properties; controlled release; Effectiveness; Encapsulation; Fosthiazate; Melamine; Meloidogyne incognita; microcapsule; Microcapsules; Microencapsulation; Nematicides; nematode; Nematodes; pesticide; Pesticide formulations; Pesticides; Simulation; Soil chemistry; Soil conditions; Soil degradation; Soil investigations; Soil mixtures; Soil properties
• ISSN: 1526-498X; 1526-4998; 1526-4998
• DOI: 10.1002/ps.8231

BACKGROUND Although microencapsulation technology is an effective pesticide formulation method, the correlation between the release properties of microcapsules and pesticide concentrations in soil and their efficacy has not been thoroughly investigated. Here, the effects of the release properties of the nematicide Fosthiazate (FTZ) from microcapsules on their efficacy against the nematode Meloidogyne incognita were examined using experimental and mathematical approaches. RESULTS Gradual release of FTZ from both polyurea microcapsules (PU‐MC) and melamine‐formaldehyde microcapsules (MF‐MC) was observed over 30 days in the release test, and each release curve was completely distinct. In the biological test, the efficacy of both microcapsules against M. incognita 42 days after the application was 8–15% higher than that of the non‐encapsulated FTZ at a concentration of 2.0 mg FTZ kg−1 soil. Soil degradation experiments suggested that the microcapsules worked effectively to protect the FTZ from degradation, which resulted in higher efficacy at a later stage. A simulation study to predict the concentration of FTZ outside the microcapsule found that the timing of supplying FTZ was important and suggested that the mixture of non‐encapsulated FTZ (non‐MC) and MF‐MC showed enhanced efficiency for the entire cultivation period in the biological test; the efficacy against nematodes was also confirmed by the measurement of nematode density using the Bearman funnel method. CONCLUSION The release properties of FTZ from microcapsules are critical for their effective application against M. incognita, and the established simulation study is a useful step in designing suitable release properties under complex soil conditions. © 2024 Society of Chemical Industry. The smart hybrid application using microcapsule suggested by simulation study on Fosthiazate concertation transition in soil (MX(75)) exhibited 30 times higher efficacy against nematode than slow‐release type microcapsule formulation (melamine‐formaldehyde microcapsules (MF‐MC)).