Grapes do not ripen off the vine, so pick them when they are completely ripe. Use a sharp knife or small pruner to cut the bunches. Bees and wasps may occasionally light on the grapes to feast on some sweet juice, so watch for them.

Your first planting of grapes may escape insect or disease attacks for a while, but eventually some trouble usually arrives. In humid areas, mildew diseases can be a problem; European grapes are very susceptible to downy mildew, for example. Black rot, caused by a fungus, develops in warm, moist climates of Eastern states. Anthracnose, another fungus disease, flourishes in wet spring weather. Japanese beetles, aphids, and mites are common garden insects that you may find. The grape berry moth is a pest in central and eastern regions. Larvae of the moth feed on buds, blossoms, and berries, tying berries together with silken threads as they feed. Two generations usually occur. Clean up grape leaves in the fall to reduce the number of overwintering pests. The following spring, cultivate around plants to turn up overwintered pupae. The grape phylloxera is a pest common in California, where it attacks roots by sucking juices from them and creating galls, and in the East, where it attacks leaves as well as roots. Galls about the size of peas form on leaf undersides. American varieties are resistant, but other types are not. No chemical controls exist; if you have a severe problem, grow American types or European varieties with resistant American rootstocks.