Kaolin Particle Films for Citrus Under HLB Pressure

Tacy Callies HLB Management


Managing the Asian citrus psyllid (ACP) that spreads citrus greening disease (HLB) has become a crucial task at the forefront of much research. One management option that has proven to reduce ACP populations while increasing tree growth and yield is particle film.

During the 2020 virtual Florida Citrus Industry Annual Conference, University of Florida Institute of Food and Agricultural Sciences assistant professor Christopher Vincent presented his research comparing red and white kaolin particle films with foliar insecticides.

Particle films are fine particles applied to plants to form a thin residue that coats the leaf surface. The films reflect light, giving the plant a bright or white appearance. According to Vincent, the film covers up the natural leaf color that attracts insects.

Although only white kaolin is commercially available to growers at the moment, researchers have discovered that red-dyed kaolin could be even more effective. According to Vincent, both natural white and red-dyed kaolin reduced ACP populations by more than 80 percent when compared to monthly foliar insecticide treatments.

In addition to reducing ACP populations, both red and white kaolin films were proven to increase tree growth and maintain higher growth — with and without HLB infection. The films also improved leaf water status by reducing water loss and keeping leaf temperatures within an optimal range.

Just like any other HLB management option, particle films are not without challenges.

The major challenge in Florida is the ability of particle film to withstand rainfall. Florida’s frequent rains tend to wash off the particle films, which are only effective as long as they cover the entire leaf. Although the treatment can be reapplied after rainfall, it can drive up grower costs.

In California, growers use particle films to protect plants from sunburn. However, according to Vincent, many California growers have noticed that in desert-like conditions, they have difficulty adhering particle films to new foliage. Additionally, the films have disrupted natural enemies, which has caused California red scale outbreaks.

Researchers are currently working on solutions to these issues so that growers can effectively decrease ACP populations and control HLB infections.

See more on Vincent’s particle film research.

Ashley Robinson, AgNet Media communications intern, wrote this article.