Aphid Damage on Milkweed
Aphid feeding is a common injury on milkweed leaves. But, aphid damage is rarely confused with ozone injury. Both have distinct edges and are interveinal (found between veins not across the veins), but the similarity stops there. See the white flecks in the picture below? That is aphid damage. You can often see this damage on the underside of the leaf too. Compare this photo with the photo of ozone injury. Do you see the difference?