Harvest berries when they're sweet and ripe. Eat them promptly or freeze them. Berries do not keep ripening after harvesting. For best flavor and ease of picking, wait until they are fully ripe. Some raspberries offer a slight resistance to picking even when fully ripe. Let your taste tell you when to pick. Red raspberries vary in color at maturity from light to dark red. Some purple ones change from red to purple to almost black, with sugar levels increasing as the color darkens. Raspberries slip off the stem when picked, leaving a hollow inside the fruit.
Pick your berries as early in the morning as possible, when they are cool. If the berries are wet, let them dry before picking. Handle them gently and place, don’t drop, them into a shallow container. Refrigerate immediately.
It’s easier to pick berries with both hands free. Tie two long strips of sturdy cloth like apron ties to a large tin can or small bucket. Tie your picking can around your waist, or hang it around your neck. Put your berry basket in the bottom if you like. Carry an extra basket to put overripe or moldy berries in as you pick; removing these berries will help prevent rot problems from occurring later.
Problem Prevention and Control
Several fungi diseases may attack raspberries. Powdery mildew can cause a white coating on fruit, leaves and shoots. Anthracnose produces dark blotches on canes and possibly sideshoot dieback. Cane blight causes wilted shoot tips and dark spots on the canes. Proper pruning, as previously described, should prevent many of the problems. If these diseases were a problem the previous year, spray with lime-sulfur when the buds begin to turn green. Check catalogs for resistant cultivars.
Viruses may produce stunted growth, curled, yellow-marked leaves, and/or crumbly, malformed berries. There is no cure; dig and destroy infected plants. Start a new patch in a different site with certified virus-free plants.
Crown gall can cause lumpy swellings on the roots and the base of shoots. Dig up and destroy infected plants. Replant new stock in a different site. Avoid wounding stems.
Bright orange spots on the undersides of leaves in spring indicates orange rust. This incurable disease attacks black and purple raspberries, as well as blackberries. Remove and destroy infected plants.
Gray fuzz on the fruit indicates fruit rot. Pick and destroy infected berries. Gather ripe fruit daily.
Borers are insect pests that damage canes, causing wilted shoot tips. Look for a small entry hole near the base of the wilted area. Prune off damaged tips or canes, borer and all. If the shoot tip is wilted but you don't see an entry hole and if the inside of the cane is discolored, a disease may be the culprit; cut off the cane at the base and destroy it.
This article is courtesy of Rodale's Ultimate Encyclopedia of Organic Gardening.