Recently, have you noticed a number of scorched plants? Leaves with brown (necrotic) spots, as well as brown margins or even the entire leaf? Then perhaps those plants suffered from the latest period of vog that the east side of the Big Island has experienced. Different plants have varying degrees of susceptibility to the vog. Consequently, a number of plants will not be affected at all, whileothers will exhibit a slight burn to outright death of the plant.
Plants adversely affected by the elevated levels of sulfur dioxide may show symptoms of foliar necrosis due to death of the plant cells (the burnt look), reduced chlorophyll content, decreased plant growth, entire death of the plant and a greater susceptibility to disease.
Some leaves may exhibit a bleaching effect as the tissue turns white.
What you can do: adequately rinse leaves with water after exposure, grow plants under cover such as greenhouses, or temporarily cover valuable plants with fabric or plastic.
Plants that have been documented to be susceptible to vog include:
— Ornamentals: African lily, Oriental lily, cypress, Dutch iris, eucalyptus, ginger, hydrangea, heavenly bamboo, pine, podocarpus, rose and tuberose.
— Native plants: koa, naio, pilo, uki, akala.
— Vegetables: broccoli, cauliflower, Chinese cabbage, daikon, lettuce, Swiss chard, tomato and watercress.
Some of the more resistant plants are asparagus, celery, coffee, corn, and ohia.
For more details on the vog and its effects on plants, read “Volcanic Emissions Injury to Plant Foliage,” by Scot Nelson and Kelvin Sewake, University of Hawaii Department of Plant and Environmental Protection Sciences.
