Preparation of rosin + sodium alginate film and its control efficacy on Nilaparvata lugens

To study the new materials for the control of Nilaparvata lugens, sodium alginate and peptone were used as water phase, rosin + sodium alginate film was prepared by adding oil phase composed of rape oil and rosin, and optimizing the ratio of oil phase to water phase. The physicochemical properties and performance indexes such as pH value, viscosity, solid content, film formation time and resistance to rain water erosion were determined, and the indoor inhibition activity and field control efficacy of rosin + sodium alginate film on Nilaparvata lugens were determined by rice straw spray method. The results showed that when the mass fraction of sodium alginate, peptone, rosin and rapeseed oil was 3%, 8%, 12.5% and 10%, respectively, the drawing degree, viscosity and ductility of rosin + sodium alginate film reached the optimal value, showing weak acidity, the pH value was between 6.34 and 6.91, the viscosity was 108 -114 Pa·s, and the solid content was 38.62%. Indoor inhibition activity showed that after being treated with 50 times diluted film for 3 days, the body weight of Nilaparvata lugens decreased significantly, the weight loss rate was as high as 92.78%, and the corrected mortality rate was only 20%. After being treated with 100 times diluted film for 7 d, the corrected mortality of Nilaparvata lugens was 59.26%. The results of field control experiment showed that the control efficacy of 50 times diluted film on Nilaparvata lugens was similar to that of 20% isoprocarb EC diluted 1500 times, and the control efficacy on Nilaparvata lugens after 7 days were 64.21% and 64.04%, respectively. This study shows that rosin + sodium alginate film has a good control efficacy on Nilaparvata lugens and has potential application value, which provides a new idea for the control of diseases and insect pests in the field.