Preparation and activity of sodium carboxymethyl cellulose (CMC-Na) and Metarhizium rileyi ZHKUMR1 composite membrane

Improving the adhesion capability of Metarhizium rileyi ZHKUMR1 on leaves enabled by the combination with Carboxymethyl Cellulose (CMCNa) materials is feasible to improve the utilization rate of Metarhizium rileyi. Herein, the CMC-Na-ZHKUMR1 membrane was prepared by simply mixing Carboxymethyl Cellulose (CMCNa) with Metarhizium rileyi. Through compatibility test, it was found that the inhibition rates of spore germination and mycelial growth of ZHKUMR1 were only 1.51 % and 3.13 % when the concentration of Carboxymethyl Cellulose (CMCNa) was 0.5 %. By adding 2 % of Carboxymethyl Cellulose (CMCNa) under UV irradiation for 30 min, the protective rate of spore germination of ZHKUMR1 was up to ~12.44 %, where the wettability on corn leaves was achieved and the retention of ZHKUMR1 spores on corn leaves was increased. After indoor activity determination, it was found that after 3 min of simulated rain washing, the lethal rate of corn leaves pretreated with CMC-Na-ZHKUMR1 on the 2nd instar larvae of Spodoptera frugiperda was 46.67 %, which was much higher than that of ZHKUMR1 spore suspension alone. This work clearly showed that Carboxymethyl Cellulose (CMCNa) effectively improved the field application effect of Metarhizium rileyi ZHKUMR1, and this strategy provided guidance for improving the field efficacy of Metarhizium rileyi ZHKUMR1.