Fungicides and biological control agents against Rhizopus soft rot in strawberries

Abstract Strawberries are susceptible to several diseases, including soft rot, which is often caused by Rhizopus species . Accurate identification of the causal agents and the identification of effective treatments to mitigate this problem are important for the sustainability of strawberry production during postharvest. This study aimed to identify two isolates of Rhizopus responsible for soft rot in strawberries, as well as to evaluate the efficacy of commercial fungicides and biological products in the preventive control of the disease. Two separate experiments were conducted per isolate: one using wounded fruit inoculated with a spore suspension in water, and another using nonwounded fruit inoculated with a suspension containing strawberry juice, simulating contamination during commercialization when juice from damaged fruit contacts the surface of others. The two isolates were identified as Rhizopus stolonifer and R. koreanus . Biological products, in general, did not significantly reduce disease incidence, but Serenade reduced the risk of R. stolonifer causing disease when inoculation was performed without wound with juice. The fungicide fludioxonil provided 100% control for both species and inoculation methods. The fungicides iprodione, boscalid, fluazinam, and cyprodinil showed moderate efficacy in controlling the disease. For integrated management of soft rot, these fungicides can be recommended as strategies to manage the disease in strawberries.