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Red Kaolin Particle Film to Protect Citrus Crops and Improve Growth and Water-Use Efficiency

Repels Asian Citrus Psyllid Pests that Cause Citrus Greening and Reduces Water Demand

These colored particle films coat citrus plants to repel insect pests and improve water-use efficiency, protecting crops from citrus greening and increasing growth in dry conditions. Huanglongbing disease, commonly known as citrus greening, threatens Florida’s $9.3 billion citrus industry, as well as those in California, Texas, and Arizona. Citrus greening spreads through the Asian citrus psyllid, an insect that feeds on citrus leaves and identifies them by their reflected yellow and green light. Using insecticides to reduce the population of these pests can be harmful to the environment and non-target species. Researchers at the University of Florida have developed colored particle films that alter the visual appearance of citrus foliage, preventing Asian citrus psyllids from targeting them for food. The red-dyed kaolin coatings more effectively reduce insect populations than available white kaolin coatings and greatly increase water-use efficiency of the crop to improve growth during dry seasons.



Citrus crop particle film that protects against citrus greening and improves growth in dry conditions and may have similar effects in other crop systems



  • Repels Asian citrus psyllid, protecting crops against the spread of the citrus greening disease
  • Increases water use efficiency, improving growth during dry seasons
  • Reduces water demand of trees already infected with citrus greening, partially maintaining growth despite weakened roots and veins


These colored kaolin films physically and optically repel insects like the Asian citrus psyllid. The red-dyed films alter the reflectance of citrus leaves, which inhibits insect populations’ ability to target the crop as food. Together with physically impairing feeding, movement, and egg placement, this reduces the spread of the citrus greening disease. To prepare the colored kaolin, researchers dissolve dye into a solution of water and cetylpyridinium chloride, and then incorporate it into a kaolin mixture for approximately two hours. Adjusting the dye-to-surfactant ratio reduces any potential leaching of the dye.

Patent Information: