What’s Wrong with this Leaf
by Sandy Swegel
What do you do when one of your plants suddenly starts looking like it’s sick. I mentally go through a list of things I’ve seen before. Is it powdery mildew? Is that grasshopper damage? If the plant is next door to a yard that doesn’t have a single dandelion, I might ask myself if the problem is pesticide overspray or runoff from the neighbor’s chemical use. But I learned yesterday there’s a whole category of plant injury I don’t often think about. Ozone or air pollution damage.
A scientist from CU-Boulder and NCAR, as part of climate change research, planted two ‘ozone” gardens in Boulder to test the effects of air pollution on plants. Yikes! Unseen air pollution like ozone can really hurt plants. It may just be speckling on leaves, or it might be damage that kills the plant. Our air looks and feels clean and crisp, but our plants tell the real story that invisible air pollution can hurt plants (and us). Ozone air pollution especially affects plants close to the ground like watermelon, beans, even raspberries.
NASA has also done ozone research and concluded: “Ozone interferes with a plant’s ability to produce and store food. It weakens the plant, making it less resistant to disease and insect infestations.
Yikes, there’s not a lot you can do in your garden plot about ozone damage in mid-summer on plants in full sun. The plants are breathing in the ozone just like you are. Some plants are more susceptible than others so if you live in an area with a lot of air pollution, you can grow more resistant plants.
Now when something is wrong with your plants, you have to ask yourself:
Is it a fungus? Is it a pest? Is it the water? Is it the soil? Is it the air?