Particle Film Technology Research Articles

Particle Film Application Influences Apple Leaf Physiology, Fruit Yield, and Fruit Quality

Particle film technology is a developing pest control system for tree fruit production systems. Trials were performed in Santiago, Chile, and York Springs, Pa., Wenatchee and Yakima, Wash., and Kearneysville, W. Va., to evaluate the effect of particle treatments on apple [Malus sylvestris (L.) Mill. var. domestica (Borkh) Manst.] leaf physiology, fruit yield, and fruit quality. Leaf carbon assimilation was increased and canopy temperatures were reduced by particle treatments in seven of the eight trials. Yield and/or fruit weight was increased by the particle treatments in seven of the eight trials. In Santiago and Kearneysville, a* values of the fruit surface were more positive in all trials although a* values were not increased in Wenatchee and Yakima. Results indicate that particle film technology is an effective tool in reducing heat stress in apple trees that may result in increased yield potential and quality.

Progress Toward Liquid Formulations of Particle Films for Insect and Disease Control in Pear

Particle film technology is aimed at controlling both arthropod pests and diseases of plants with a hydrophobic particle barrier primarily composed of kaolin. Field studies were conducted from 1996 to 1998 to compare the efficacy of dust and liquid applications, and hydrophobic and hydrophilic particle films, against key pests of pear. In addition, the effects of particle film applications on pear yield and quality were investigated in 1998. Dust and liquid applications of hydrophobic and hydrophilic particle films obtained high levels of early-season pear psylla control and prevented pear rust mite damage. We also found that prior seasonal applications of particle films in 1997 can carry over into the 1998 season to suppress early season pear psylla oviposition. A major concern in the shift from hydrophobic to hydrophilic particle films was the loss of disease control. We found that a water-repellant particle film was not required to control the fungal disease fabraea leaf spot. Pear yields were nearly doubled by liquid formulations of hydrophobic and hydrophilic particle films. Particle film deposits were measured using a spectrophotometer method we developed. Particle deposition differed among formulations for both leaf age and leaf surface (top or bottom). Yet, the particle formulations performed about the same against insects and fungal diseases, and in how they influenced the horticultural traits. None of the particle film formulations were found to be phytotoxic to pear foliage or fruit during the study period. A shift from hydrophobic to hydrophilic particles makes it possible to more easily formulate and disperse the particles in water so that conventional spray equipment can be used. The multifunctionality and low toxicity of particle films could make them an attractive alternative to conventional pesticides.

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.

253 The Use of Particle Film Technology in Tree Fruit Production

Particle film technology uses inert mineral particles to envelope a plant in a protective and porous “particle film.” The film appears to protect against insect damage by creating a hostile and unfamiliar environment, causing nonrecognition of the host, acting as an irritant, and giving poor adhesion or gripping of eggs and insects to the plant surface. Being porous, the particle film allows free exchange of water and carbon dioxide from the leaf during photosynthesis. The mineral particles are reflective of infrared radiation and reduce the heat load on the plant. Laboratory, greenhouse, and field trials demonstrate that particle film technology is a viable pest control practice for a wide range of insect and disease problems with additional horticultural benefits due to reduced heat stress. In field studies, reducing heat stress improved red apple color development, increased leaf photosynthetic rates, and increased yield. Particle film technology appears to be a viable alternative to conventional pesticide use in apple and pear production. Particle films have the added benefits of reducing plant heat stress and improving safety to farm workers, consumers, and the environment.

Hydrophobic Particle Films Improve Tree Fruit Productivity

Hydrophobic particle film technology (HPF) is a developing pest control system for tree fruit production systems. Studies were established in Chile, and Washington, Pennsylvania, and West Virginia in the United States, to evaluate the effect of HPF technology on tree fruit yield and quality. Studies in Chile, Washington, and West Virginia demonstrated increased photosynthetic rate at the leaf level. Yield was increased in peaches (Chile) and apples (West Virginia), and fruit size was increased in apples (Washington and Pennsylvania). Increased red color in apple was demonstrated at all sites with reduced russetting and `Stayman' cracking in Pennsylvania. HPF technology appears to be an effective tool in reducing water and heat stress in tree fruit resulting in increased fruit quality.