Common Currant Disease Problems
Anthracnose: This is a fungus disease that attacks the fruit as it is ripening. The first visible sign is a circular spot on the skin that is slightly sunken. The spots enlarge and turn black; the fruit rots. Extended periods of heat and humidity facilitate anthracnose growth. The fungus overwinters in diseased plant debris. Burpee Recommends: Plant resistant varieties, provide sufficient space between plants for good air circulation, avoid overhead watering which can spread the fungus spores, keep a clean garden, remove and discard all diseased plant material and rotate crops. Use a mulch to prevent spores from splashing from the soil onto plants.
Botrytis: This fungus causes a grey mold on flowers, leaves, stems and buds. It thrives in cool wet weather conditions. Burpee Recommends: Remove affected plant parts, avoid watering at night and getting water on the plant when watering. Make sure plants have good air circulation. Contact your Cooperative Extension Service for fungicide recommendations.
Powdery Mildew occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.
Septoria Leaf Spot: This disease causes severe losses in the Atlantic and Central states. It is most severe during rainy seasons in closely planted gardens. It usually appears when the plants begin to set fruit. Circular spots with gray centers and dark margins appear on the lower older leaves. Fungal spores are produced and darken the center of the spots. There is a progressive loss of foliage and fruits suffer from sunscald. Burpee Recommends: Remove and destroy infected plant debris. Don't handle or brush against plants when they are wet. Rotate plantings. Remove weeds growing nearby.
White Pine Blister Rust: Small yellow spots appear on the underside of the leaves in spring. In late summer yellow to brown threadlike growths appear on or near the spots. The growths produce spores that will spread the disease to pine tree, the alternate host. Burpee Recommends: Plant resistant varieties. Do not plant near to pine trees. Avoid wetting the leaves when watering. If it is a bad infection remove and destroy plant. There are no effective pesticides to control White Pine Blister Rust.
Common Pest and Cultural Problems for Currant Plants
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Currant Borer: The larva is pale yellow and wormlike. The female lays eggs on the canes in early June. The worm hatches and enters the cane and feeds all season. Larvae overwinter in the infested cane, emerging in the spring as an adult. The first symptom is yellow leaves on individual canes in late spring. Canes will die in summer. Burpee Recommends: Remove and destroy infested canes as early as possible.
Gooseberry Fruitworm or Currant Fruit Fly: Signs include hollow fruit or small maggots inside fruit. Fruit may drop early and have dark spots surrounded by red areas. Burpee Recommends: Remove all dropped fruit and destroy. Plant early-maturing varieties. Contact your local Extension Service for pesticide recommendations for your area.
Scale: Small bugs look like brown, black, gray to white bumps on the stems of plants. Scale may not have any apparent legs and may not move. Scales have a sucking mouth part. Scale may produce honeydew so leaves and stems may be sticky. Scale can weaken the plant causing it to grow very slowly and may wilt at the middle of the day. Burpee Recommends: Completely spray the stems with insecticidal soap. For a severe infestation contact your local County Extension Service for recommendation for your area.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Do I need two different varieties to get fruit? Red currants do not need a second variety. Black currants produce better if you have 2 different black varieties. Red and black currants are two different species and will not cross with each other.
Will I get fruit the first year? No, expect the first fruit in 2 years after planting, and 3-5 years after planting for full fruit.
How long will currants produce fruit? Currants are extremely long lived and if properly taken care of can last 20 to 30 years.
Are currants deer resistant? Deer may eat some leaves but generally leave the fruit alone. However if you have a lot of deer and little food they may eat the berries.
Is the currant related to the jostaberry? Yes, a jostaberry is a cross between a gooseberry and a currant. It is sweeter than a currant.