Clean up your grapevines. It’s too late to safely spray fungicide to prevent black rot on grapevines (guignardia bidwellii), so your best bet is to remove as many of the affected, spotted brown leaves as you can without totally denuding the vine. Grape flowers in the city are blooming profusely, putting out a wonderful scent of Old Spice, reminiscent of my dad in his younger days.
Recognize that some damage is OK. Recently a reader sent me pictures of his echinacea leaves with big chunks taken out of them. At first I thought slugs, but the damage was higher on the plants, and there were no visible slime trails (always my favorite!). Because the holes were rounded, I suspect leaf-cutter bees, Megachilidae. Smaller than bumblebees, they sit on the leaf and saw off a circle around themselves. Just as they’re about to fall through, they fly away with the chunk of leaf in their mouth, using the leaf to wrap their eggs, and packing their nests into holes wherever they can find space in logs and branches. It’s really kind of an amazing process, and it doesn’t seem to damage the flowers at all. If this is what you have, do some research and find out how you can encourage these gentle, native, solitary pollinators to move into your garden.
Get friendly with your storm sewer. Clean out your gutters so that leaves, trash, and tree detritus aren’t washing down and clogging things up. My own personal storm sewer is covered by a piece of chicken wire fencing so that I can control my own flotsam and jetsam; it also discourages the raccoons from using it as a thoroughfare. Permeable pavers or concrete will also help keep heavy rains from washing all the stuff out of your driveway into the street.