Pests vary from the very large (deer, bear) to the very small (fungal infections). Animal pests are especially problematic in the lead up to harvest. Before veraison, the stage at which grapes turn color, they are very tart. Only closer to harvest do they start to accumulate more sugars making them very tasty for the birds, deer and bear. Vineyard managers likely will cover the vines in nets at this time or employ a sound cannon to scare of the pests. Fences are also employed where possible.
Insect pests like leafhopper and cutworm are present in BC. There are a few isolated areas of phylloxera, but it does not appear to be spreading and fails to thrive on the sandy soils of the southern Okanagan Valley. There has been no reported incidence of Pierce’s Disease. Insect pests can be controlled by introducing predators, using conventional pesticides or creating a more attractive biosphere for them by leaving the grass uncut between the rows of vines.
Due to dry climate in the Similkameen Valley and the Okanagan Valley, fungal diseases are limited, although powdery mildew is common. In wetter climates botrytis bunch rot can occur.