Now you can measure spraying coverage using only your smartphone!

DropLeaf - Deposition Analysis™ automatically measures the efficacy of spraying methods and nozzles using images of water-sensitive papers (spray cards) either captured from a smartphone or loaded from the photo gallery.


Pest Control

Pesticide application has been heavily used in the cultivation of major crops, contributing to the increase of crop production over the past decades. However, the overdosage of pesticides can contaminate the food, harm the human health, and pollute the environment. In contrast, under dosage might cause pest and/or weed resistance or behavioral avoidance. As a consequence, the incorrect application can lead to severe economic losses. Thus, quantifying the amount of sprayed pesticide is important to assisting experts and farmers to take better decisions related to the evaluation of pesticide management, by controlling weeds, insects, nematodes, and plant pathogens.


Water Sensitive Paper

There exist different ways to measure spray deposition. The most used method includes using water sensitive papers (WSP). WSP is a special paper card coated with a bromoethyl dye that stains to dark blue when liquids fall on it. Before spraying, experts place several of them in target areas. The major drawback of WSP is that the assessment is performed visually using handheld lenses, and comparing the card side-by-side with known spray patterns. In this context, we proposed the DropLeaf - Deposition Analysis to easily control and assess the spraying of pesticides.

Quantitative Analytical Parameters

DropLeaf deals with drops of any size as found in spray card images, counting them and measuring their diameter. In addition, our application can measure the most used parameters for the evaluation of sprayers, including:

  • Number of Drops
  • Average of Diameters (micrometer)
  • Drop Density (drops/cm2)
  • Area Coverage (%)
  • Volumetric Median Diameter (VMD or Dv)
    • Dv 0.1 (micrometer)
    • Dv 0.5 (micrometer)
    • Dv 0.9 (micrometer)
    Coming soon the measures below.
  • Numeric Median Diameter (NMD) (micrometer)
  • Coefficient of dispersion



Spraying Fractal Pattern Measurement

The image of the spray pattern is also analyzed by fractal dimension. We have explored two fractal-based models to assess the space occupation and the volume of drops on the WSP. This helps users to have a quantitative measure related to the level of regularity of droplet patterns on the cards. In addition, the measures related to volume are simply based on the diameter and on the area of the drop. Interestingly, the fractal dimension volumetric model shows us that the volume is not only related to the area, but with the intensity of the color blue of each drop when evaluating the exposed WSP. Notice that in the WSP image, the droplets hold different values for the z-axis, as indicated by the green arrows, which present different sizes due to the corresponding volumes of the drops.


DropLeaf is very useful for pest control.

José Raul, Researcher at Embrapa

With this application is possible to measure in a fast and an easy way the spraying coverage.

Antônio Muller, Farmer

Partners of DropLeaf