| 【Objective】The effective utilization rates and droplets distribution effects of three pesticides sprayed on
rice by manual sprayer and electric sprayer were compared.【Method】The plot experiments were carried out on pesticide
utilization rate of late rice in two towns of Huiyang District and two towns of Boluo County of Guangdong Province. The tested
pesticides included 50% pymetrozine water dispersible granule (WDG), 5% chlorpromazide suspension concentrate (SC)
and 2% kasugamycin aqueous solutions (AS), and the allura red tracers were added into the pesticide diluents. Five point
sampling method, droplet cards and spectrophotometer (501nm) were used in the research.【Results】The utilization rates
of pymetrozine, chlorobenzamide and kasugamycin on rice sprayed by electric sprayers were 39.43%, 38.03% and 38.98%,
respectively; while the rates by manual sprayers were 29.02%, 28.08% and 28.50%, respectively. Compared with those of the
manual sprayer treatment, the effective deposition rates of three pesticides sprayed by the electric sprayer increased by 10.41,
9.95 and 10.93 percentage points, respectively. Moreover, the effective deposition rates of the electric sprayer treatments were
significantly higher than those of the manual spray treatments. The results of droplets deposition distribution assay indicated
that, both of manual and electric sprayer treatments decreased gradually from top to bottom, and droplet deposition of different
layers showed significant differences. The results of droplets diameter showed that, the droplets diameters of middle and lower
layers on rice under the manual sprayer treatments were significantly higher than those of the electric sprayer treatments. The
results of droplets quantity indicated that, the electric sprayer treatments showed a downward trend from bottom to top, and the
droplet quantities of the electric sprayer treatments were also higher than those of the manual sprayer treatments.【Conclusion】
The effective utilization rates of three pesticides sprayed by electric sprayers were higher than 38% at the heading stage of late
rice in Guangdong Province, which were 9.95-10.41 percentage points higher than those of manual sprayer treatments. And the
atomization effect of electric sprayer was better than that of manual sprayer. |
