Answer: It's hard to tell for sure, but your plants might have been attacked by spider mites. These insects can cause a stippled, silvery look to the upper sides of leaves as they feed on the undersides of leaves. They are mostly a pest in mid- to late-summer, when conditions are dry and dusty. Inspect the undersides of the leaves, looking for webbing and tiny little insects. If you find them, hose the leaves off with water (both upper and lower surfaces) to dislodge the pests. Repeat each morning until you manage to control the population.
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