Pioneering results of seed-potato health improvement and the suppression of soil-borne infection during the potato production by the preplant coating of tubers with an azoxystrobin-loaded degradable polymer film coating are presented. The film coating was applied to the surface of potato tubers by spraying with a 1% solution of the degradable polymer poly(3-hydroxybutyrate) in dichloromethane mixed with azoxystrobin. The film coating did not damage the tubers or reduce germination. The half-life of the polymer coating in field soil was 25 days. The film degraded gradually from potato planting to the beginning of flowering, ensuring long-term delivery of the fungicide to the plants. In the experimental group, a more effective reduction in the total number of rhizospheric soil fungi, including plant pathogens Alternaria alternata and Fusarium oxysporum, was revealed, compared with the preplant treatment of tubers with the commercial fungicide azoxystrobin (comparison group). The healing effect of the fungicide-loaded coating led to an improvement in the quality of the potato crop. In the experimental group, the total yield and the share of marketable tubers exceeded those of the comparison group by 5.6 t/ha and 8%, respectively. The proportion of Fusarium infected tubers was 8.5% in the experimental group versus 12.1% in the comparison group. The fungicidal effect of a long-term degradable polymer film coating with azoxystrobin was more successful than traditional treatment of tubers with a solution of this fungicide. Thus, the proposed approach is promising for the protection of seed potatoes.

Pesticides and microplastics are common pollutants in soil environments, adversely affecting soil organisms. However, the combined toxicological effects of aged microplastics and pesticides on soil organisms are still unclear. In this study, we systematically studied the toxicological effects of azoxystrobin and four different aged polyethylene (PE) microplastics on earthworms ( Eisenia fetida ). The purpose was to evaluate the effects of aging microplastics on the toxicity of microplastics-pesticides combinations on earthworms. The results showed that different -aged PE microplastics promoted azoxystrobin accumulation in earthworms. Meanwhile, combined exposure to azoxystrobin and aged PE microplastics decreased the body weight of earthworms. Besides, both single and combined exposure to azoxystrobin and aged PE microplastics could lead to oxidative damage in earthworms. Further studies revealed that azoxystrobin and aged PE microplastics damage the intestinal structure and function of earthworms. Additionally, the combination of different aged PE microplastics and azoxystrobin was more toxic on earthworms than single exposures. The PE microplastics subjected to mechanical wear, ultraviolet radiation, and acid aging exhibited the strongest toxicity enhancement effects on earthworms. This high toxicity may be related to the modification of PE microplastics caused by aging. In summary, these results demonstrated the enhancing effects of aged PE microplastics on the toxicity of pesticides to earthworms. More importantly, aged PE microplastics exhibited stronger toxicity -enhancing effects in the early exposure stages. This study provides important data supporting the impact of different aged PE microplastics on the environmental risks of pesticides.