Early botrytis infection causes the berries to break open allowing insects to feed on the berries. This in fact, is not desireable. An organic botrytis spray applied just before bunch closure, is the best defense against this. An even greater problem can be the birds. A flock can easily destroy a whole year's effort leaving the rest for wasps and bees to finish.
Netting is the most effective way to control the birds.
Vidal is the best suited variety to repeated freezing. However, several selective pickings are necessary leaving only the healthiest bunches on the vine. The Ice wine can be enjoyed for several years after bottling. If you live not too far from Guelph you can visit Cox Creek Cellars north of the city on Highway 6. Click here to visit Cox Creek Cellars.