1. Dept. of Agriculture Engineering, Univ. of Catania, Via S. Sofia 100, 95123 Catania, Italy (corresponding author).
2. Subtropical Horticulture Farm Advisor, Tulare County Cooperative Extension, Univ. of California, Agriculture Building, 4437 S. Laspina St., Ste. B, Tulare, CA 93274.
3. Biometeorology Specialist, Dept. of Land, Air and Water Resources, One Shields Ave., Univ. of California, Davis, CA 95616.