Dr. Shahak presents an invited expert seminar reviewing research around the world where anti-hail shade nets of various colors have been used to alter the field microclimate and bring about various positive benefits for plants.
Dr. Shahak discussed her experience over the last 18 years of conducting research on the use of photo-selective anti-hail shade nets for their positive benefits on the production of fruit and other crops in diverse climates around the world. Dr. Shahak provided background on why protected horticulture (e.g., using overhead nets) is increasing worldwide. In terms of tree fruit crops, some of the general protective benefits of netting relate to partial shading that reduces light and heat stress (especially fruit sunburn), protection from hail and strong winds. It can also present a physical barrier to flying pests (e.g., insects, birds and bats). She reviewed the technology and how different colored nets actually change the growing environment of plants under them. In particular, she noted that some unique features of photo-selective nets (versus black shade net) include both the modification of the light spectrum that is transmitted through them and the amount of light scattering that occurs as well. The modification of the light spectrum promotes various physiological responses in the plant. The light scattering improves the penetration of the spectrally-modified light into the inner plant canopy. In terms of photo-selective netting that filters the light coming through it, she noted numerous physiological benefits observed through research and commercial practice. These crop performance enhancements related to: leaf photosynthesis and vegetative development, fruit-set, fruit size, time to fruit maturation (either advancing or delaying harvest), fruit coloration, fruit quality, plant water-use-efficiency (and water savings), pest and disease infestation, plant resistance to biotic and abiotic stresses, and less decay (both pre- and post-harvest). Finally, Dr. Shahak responded with answers to questions from the audience.