Abstract: 【Objective】The objective of this study is to analyze the influence of spray method on the deposit and distribution of pesticide within the rice population, and to put forward reasonable spay technology and improve the utilization ratio of pesticide in rice field. 【Method】The solution of ponceau-G was sprayed by manual sprayer with a hollow cone nozzle upon rice plant and mist sprayer with pneumatic nozzle down 45° tilt angle at rice tillering, booting and flowering stages. The ponceau-G deposited on the microslides, which respectively showed the obverse and reverse of rice leaves and the vertical stem of plant, were collected and measured.【Result】There was a significant difference among the deposition amounts of penceau-G sprayed by different methods at different sites within the field rice population at different growing stages. The deposit rate of ponceau-G was manifested with a distribution trend of upper layer＞middle layer＞lower layer. At the rice tillering stage, manual sprayer was applied and the deposition of ponceau-G on 13.3% of microslides was close to the average value, the deposition of ponceau-G 52.9% of microslides was lower than the average value, and 33.75% was higher than the average value. At the rice tillering stage, mist sprayer with pneumatic nozzle down 45° tilt angle was applied and the deposit rate of ponceau-G on 20.4% of microslides was close to the average value, 45.4% was lower than the average value, and 34.2% was higher than the average value. At the booting and flowering stages, manual sprayer was applied and 33.3% and 28.1% of microslides did not have any deposition of ponceau-G. When mist sprayer with pneumatic nozzle down 45° tilt angle was applied, there was 13.9% and 5.0% of microslides did not have any ponceau-G deposition. The deposition of only 6.4% and 11.7% of microslides was close to the average value at booting stage for manual sprayer and mist sprayer. At the flowering stage, the proportion was 7.2% and 17.2%, respectively. For manual sprayer, ponceau-G mainly deposited on the microslides expressing obverse of leaves and the amounts were, respectively, 66.3%, 85.1% and 84. 9% of total deposits on microslides in three rice stages, among which the amount of ponceau-G on the microslides from upper layer of plant were, respectively, 38.7%, 42.2% and 45.6% of total deposition. There were litter deposition on the microslides expressing the reverse of rice leaves and the vertical stem of plant, especially on some microslides put in the base of rice plant, the amount of ponceau-G was zero at rice booting and flowering stages. For mist sprayer, the deposition on the microslides showed the reverse of rice leaves and the vertical stem of plant was more than that of manual sprayer. However, the ponceau-G on the microslides showing obverse of leaves were still 50.5%, 50.6% and 53.1% of total deposits, among which the ponceau-G on the microslides from upper layer of plant was, respectively, 32.3%, 27.9% and 31.5% of total deposition.【Conclusion】If the average of total deposition on each microslides was the pesticide dose controlling pest effectively, there were shortage and waste of dose within rice population at the same time. The fog drip of manual sprayer spraying mainly deposited on the obverse of rice leaves of plants’ upper leaves. The deposition rate accounts for above 1/3 of the total deposition amount, while the deposition rate was few on the reverse of leaves and the vertical stem, especially on the plants’ base leaves and vertical stem, on which the deposition rate was nearly zero. When mist sprayer with pneumatic nozzle down 45° tilt angle was applied, the deposition rate of fog drip on the obverse of rice leaves of plants’ upper leaves was more than 1/4 of the total deposition amount. However, when the application volume was less than that of manual sprayer conducting coping spraying, each layer of the reverse of leaves and the vertical stem was demonstrated a significantly higher deposition rate than manual sprayer. It illustrates that spraying with the mist sprayer with pneumatic nozzle down 45° tilt angle, pesticide droplets could be delivered to middle and lower layer and deposited on rice stem and reverse side of leaves.

Key words: rice , spray method , ponceau-G , deposit and distribution