Submitted to: Annals of Applied Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/3/2003
Publication Date: 7/1/2003
Citation: FULLER, M., HAMED, F., WISNIEWSKI, M.E., GLENN, D.M. PROTECTION OF CROPS FROM FROST USING A HYDROPHOBIC PARTICLE FILM AND AN ACRYLIC POLYMER. ANNALS OF APPLIED BIOLOGY. 2003 Vol. 143, pgs. 93-97. Interpretive Summary: In the United States, frost damage is common in many states every year and the consequence of these frost episodes can be very costly. Annual losses can be over a billion dollars for all crops combined. Existing methods of frost protection can be ineffective, too costly, or environmentally unfriendly. Therefore, a key mission for USDA-ARS is to develop a better understanding of freezing in plants in order to develop new methods of frost protection. In the present study, we examined the ability of hydrophobic (water-repelling) particle films to provide frost protection by acting as a barrier on the outside of the plant that prevents external ice crystals from inducing the plants to freeze. Young potato plants, citrus seedlings, and young grapevines were exposed to a freezing stress after the hydrophobic particle film was applied. The amount of damage after the frost episode in the treated plants was compared to uncoated (control) plants and plants coated with a commercial, frost-protection material. Th plants treated with the hydrophobic particle film had significantly less damage than either the control plants or those sprayed with the commercial, frost-protection material. A detailed analysis of the plants using thermal imaging indicated that the hydrophobic particle film delayed externally- induced freezing by as much as 270 minutes or longer. The use of the hydrophobic particle film represents a new method of frost protection and has been patented by the USDA-ARS. Further field research will be conducted in order to determine the potential of this technology as a practical and economical method of frost protection.
Technical Abstract: Frost damage to potatoes, grapevine and citrus plants was assessed following treatment with either an acrylic polymer or with a hydrophobic kaolin particle film. In large freezing tests the application of the hydrophobic particle film consistently led to less damage while the acrylic spray led to more damage in comparison to control plants. Detailed examination of the freezing of leaves of all three species using infrared thermal imaging revealed that the hydrophobic particle film delayed the entry of ice from a frozen water droplet containing ice-nucleating-active bacteria by between 5 and 270 minutes and in some cases for the complete duration of the frost test. In contrast, the acrylic polymer was only able to influence the time of ice nucleation of the leaves of citrus. It was concluded that the hydrophobic particle film has potential as a frost protectant applied to susceptible crops just prior to a freezing event.