Frequent harvesting also decreases infection by diseases. Ripe fruit is plump and has even color. Table grapes will taste sweet when ripe, while wine grapes are slightly tart. Two pests that threaten backyard grape crops are the grape berry moth and birds. Larvae of the grape berry moth feed on grapes and make them worthless.
Birds simply enjoy eating grapes.
Control of these pests is difficult. However, Cuyahoga Fact Sheet 701, Reference Fruit.3, describes how to deter these two pests through the use of paper bags. These traps are used to identify the presence of pests, not as a control.