Novel ready-to-use dry powder formulation of Talaromyces tratensis KUFA0091 to control dirty panicle disease in rice

Abstract

The dry powder formulation of the antagonist Talaromyces tratensis KUFA 0091 was developed by culturing the fungus in sterile cooked rice for 30 days and drying at 80 °C for 5 h using a hot air oven. Then, the dry moldy rice was ground to a fine powder using a high power grinder to obtain a ready-to-use biofungicide and growth promotion agent. The spore concentration in this formulation was evaluated every month for 12 months and the average spore content was found to be 106 cfu/g. Rice seedlings grown from seeds treated with low concentrations of the dry powder formulation (1%) and the crude extract (1 g L−1) of T. tratensis KUFA 0091 displayed significantly increased growth compared with controls. The formulation was optimized at 1%, 5% and 10% with or without 1% of dimethyl sulfoxide or carboxymethyl cellulose for control of rice dirty panicle disease under field conditions. The results showed that two applications of the dry formulation of T. tratensis KUFA 0091 at 10% without adjuvants resulted in the maximum antagonistic activity against dirty panicle disease of rice by a 50% reduction and a 24.06% increase in rice yield over the control treatment. The control efficacy was not significantly different from that of treatment with the fungicide difenoconazole + propiconazole. The adding of solvents, either dimethyl sulfoxide or carboxymethyl cellulose, did not improve the efficacy of the dry formulation of T. tratensis KUFA 0091. The results in this study showed this new technology formulation of the heat tolerant antagonist T. tratensis KUFA 0091 has potent antagonistic activity against rice disease coupled with plant growth promotion capability useful in rice production.