[Development and application of Jingcen DY-1 spraying tanker for Oncomelania hupensis snail control]

To develop a Jingcen DY-1 type spraying tanker for Oncomelania hupensis snail control and evaluate its effect of field application as well as the cost.

The currently available tractor was used as a vector, and the mechanical and electrical equipments and containers were integrated with shafts, pipelines and electric lines to produce a spraying tanker for snail control, with the functions of carrying people and molluscicides, generating electric power and getting water, mixing stocking solutions, adjusting molluscicide solutions evenly, and spraying drugs. The volume of the molluscicide solution, flow rate of water injection, and the flow rate, range and advance speed of the spray gun were tested, and the solution concentrations of molluscicide in the tanker and at the muzzle of the spray gun at different time were detected. Meanwhile, the molluscicidal effect and cost of the spraying tanker were analyzed by the field test.

The volume of the liquid storage pot of the Jingcen DY-1 type spraying tanker was 1 800 L, the flow rate of water injection was 400 L/min, the flow rate and the spray range of the standard spray gun were 110-200 L/min and 19.70-23.50 m, respectively, the efficiency of drug spraying of the spraying tanker was 6 000 m/h, and the ratio of spray width (m) to march speed (m/min) was 1:200. When 5 min post mother liquid recirculating, the average concentration of the molluscicide at the upper-, middle- and lower-layers of the liquid storage pot was (1030.39 ± 43.00) mg/L, with a variation coefficient of 4.17%. The average concentration of the molluscicide in the spraying process (spraying for 2, 4, 6, 8, 9 min) was (953.00 ± 68.87)mg/L, with a variation coefficient of 7.22%. The concentration of the residual drug in the liquid storage pot post spraying was 1 000.43 mg/L, which reached the effect concentration for snail control. After spraying for 7 days in the field, the average density of living snails reduced by 88.20% as compared to that before spraying, and the adjusted mortality of snails was 87.65%. The unit cost of Jingcen DY-1 spraying tanker was 0.086 7 Yuan/m². which reduced by 58.20% as compared to that of the conventional spraying tanker.

Jingcen DY-1 type spraying tanker for snail control which integrates various equipments together can effectively control the concentration and dose of the molluscicide, and the machine is labor-saving, efficient, economic and well adapted, and is worthy to be widely applied.