Submitted to: Horticultural Reviews
Publication Type: Book / Chapter
Publication Acceptance Date: May 17, 2004
Publication Date: January 21, 2005
Citation: Glenn, D.M., Puterka, G.J. 2005. Particle film technology: a new technology for agriculture. Horticultural Reviews. Vol. 31, Ch 1. Technical Abstract: Scientific evidence that chemically active pesticides are residually present on food, in water supplies, in the soil, and that these chemicals may interfere with animal growth and development, together with the public demand for reduced-risk pesticides, resulted in a Congressional mandate for USDA-ARS to develop reduced risk alternatives to chemical pesticides in 1985 as part of the Low Input Sustainable Agriculture (LISA) program. In the 1980s and 1990s it was clear that new paradigms were needed to control plant pests in an economically sustainable and environmentally safe manner. Particle film technology is a combined synthesis of knowledge on mineral technology, insect behavior, and light physics as they apply to pest control and plant physiology. Particle film technology is based on kaolin, a white, non-porous, non-swelling, low-abrasive, fine grained, plate-like, aluminosilicate mineral (Al4Si4O10(OH)8) that easily disperses in water and is chemically inert over a wide pH range. Water-processed kaolin is >99% pure and has a high brightness quality of >85%. Mined, crude kaolin has traces of Fe2O3, and TiO2 that are removed during processing to increase brightness. In addition crystalline silica, SiO2, a respirable human carcinogen, must be removed to insure human safety. Technical advances in kaolin processing within the past decades have made it possible to produce kaolin particles with specific sizes, shapes, and light reflective properties. Kaolin particles can be engineered with specific properties for paper, paint, cosmetic, and plastic applications. Potential uses of kaolin, however, have been largely ignored by the agricultural industry but have been used as carriers for wettable powder formulations of pesticides. The advances in kaolin processing, coating, and formulating, and plant surface deposition have opened new opportunities for its use in agriculture. An effective particle film can be applied to a plant surface in such a way that a nearly uniform layer is deposited over the entire plant without blocking stomates. Another key criterion of an effective particle film that is the ability to removed white residues from the harvested commodity. At the present time, a commercial particle film material, Surround® crop protectant, is being used in about 50% of the Pacific Northwest pear market for the early season control of pear psylla and approximately 20% of the Washington state apple market to reduce sunburn damage. The purpose of this paper is to bring together the historical and current literature related to the use of particle films in agriculture and to discuss their present and future use in crop protection and production.