Hydrophobic particle films: a new paradigm for suppression of arthropod pests and plant diseases

We introduce a unique concept, hydrophobic particle film technology, that represents the combined synthesis of knowledge on the use of hydrophobic films, physical particle barriers, and white reflective surfaces to suppress arthropod pests and diseases of agricultural crops. The hydrophobic particle film is based on the inert mineral, kaolin, that is surface treated with a water-repelling agent. We demonstrate suppression of important tree fruit arthropod pests and diseases by altering the plants surface with dust applications of these hydrophobic particles. There are a number of potential mechanisms involved in pest suppression. Arthropods can be repelled from, or infestations suppressed, on a plant coated with a hydrophobic particle film barrier by making the plant visually or tactually unrecognizable as a host. In addition, insect movement, feeding, and other physical activities can be severely impaired by the attachment of particles to the arthropods body as they crawl upon the film. Diseases can be prevented by enveloping the plant in a hydrophobic particle film barrier that prevents disease inoculum or water from directly contacting the leaf surface. Thus, many fungal and bacterial pathogens that require a liquid film of water for disease propagule germination are prevented. Other key features of the hydrophobic particle film are that it reduces heat stress by reflecting sunlight with its bright white color, and does not affect plant photosynthesis or productivity because of the porous nature of the film. Our results suggest that the hydrophobic particle film concept could offer broad spectrum protection against arthropod pests and diseases in certain agricultural crops.