Preventive Control of Fusarium Proliferatum in the Initial Phase of Rice Development Through Seed Treatment.

Rice is a very important crop for the Costa Rican economy. Recently, it was found that rice can be infected by Fusarium proliferatum (Fp), however, little is known regarding the potential impact on rice. Therefore, greenhouse and laboratory studies were conducted to examine the effect of variety, seed treatment, irrigation, and/or pathogen isolates on the initial stages of rice development (first 30 days). Laboratory studies focused on isolate variation and fumonisin production by inoculating seed with one of ten isolates of Fp. Results indicated that all isolates caused greater disease and reduced root and shoot development compared with the untreated control, and there were differences among isolates. Furthermore, all isolates produced fumonisins. The greenhouse studywas conducted using a three-way factorial design of variety, irrigation and seed treatment, arranged in a randomized complete block. The two varieties were Palmar-18 and Puitá-INTA, irrigation was flooded conditions or no flooding, and seed treatments included Butrol 31.5 EC, Mertec 50SC (Thiabendazol), Trichoderma sp., oil of Thuja occidentalis. There were also two controls, without and without Fp. Similar measures to the laboratory study, except fumonisin production, were obtained. Key results indicated the Mertec 50SC provided the best control under flooded conditions, however, similar findings were not noted in non-flooded conditions. Overall, results suggest that Fp has the potential greatly impact rice production in Costa Rica and further research is needed to develop best management practices to reduce the early season risk of infection.