Insect Or Leaf Spot

Sometimes it’s hard to tell the difference between leaf-spot fungus damage, or damage caused by the splashing of something (hot water from hose, sprays used in the area etc) on the leaves and insect damage. In the case of fungus or splash-damage, the tissue dies and drops out, causing what looks like insect chewing. The insects that cause similar damage are earwigs and this is kind of typical of earwig damage in that it occurs on the lower (older) growth and not on the top leaves. Earwigs prefer eating decaying plant matter but early in the season there isn’t enough of that so they go after other things like our veggies, dahlias and butterfly bush. Then as the season goes along and there is more for them to eat, they stop feeding on our plants. In this case I’d recommend that you remove the damaged foliage just so you can more easily monitor if the problem is continuing. If the undamaged leaves remain relatively intact, the problem is solved no matter what the cause. Watch the undamaged leaves to see if they first have brown spots that later drop out – if so, this is leaf spot which is most frequently caused by splashing of water too frequently or in the late evening. Water deeply less often and try to water in the morning when possible.