Blueberry, Currant, Gooseberry

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Blueberry, Currant, Gooseberry

Author:	OMAFRA Staff
Creation Date:	25 July 2005
Last Reviewed:	20 December 2005

The Gardener's Handbook > Chapter 6: Fruit > Blueberry, Currant, Gooseberry

Blueberry
Currant and Gooseberry
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Blueberry

In Ontario, blueberries have few insect and disease problems. No domestic pesticides are registered for this crop.

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Currant and Gooseberry

Aphids

Aphids are soft-bodied, greenish to brown, 5mm, pear-shaped insects. They are often a serious problem on currants, especially red currants. They cause leaves to pucker, curl and show red blisters.

Treatment

Cultural control: None

Chemical control: If this problem has occurred before, spray when leaf buds open in spring and repeat 10 days later. Early season applications are critical, since aphids are very difficult to control once leaves are curled. For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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Currant Borers, Currant Stem Girdlers

Currant borers and currant stem girdlers cause injury to the wood of the canes. Affected shoots look sickly with small, yellowed leaves. Eventually, the shoots will die.

Treatment

Cultural control: Shoots should be cut out and destroyed when symptoms are noticed at any time of the year. Shoots older than three years are less productive and should be removed in spring before leaf buds break to minimize the potential for attack. Apply manure to promote vigorous growth of new canes.

Chemical control: None are known at this time.

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Currant Fruit Flies

Maggots in the fruit are larvae of currant fruit flies. Infested berries ripen prematurely and many drop to the ground.

Treatment

Cultural control: Remove and destroy infested berries to reduce risk the following season.

Chemical control: Treat if maggots were a problem last year. Flies must be killed before they lay eggs. For currants, spray just after bloom and again a week later. For gooseberries, spray when berries turn red.

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Currant Sawflies

The larva of the sawfly is 2.5 cm long, green, with many legs and a black spotted body. It eats the leaves of gooseberries and red or white currants (not black currants) as plants come into full leaf. The adult is a small black wasp-like insect.

Treatment

Cultural control: None

Chemical control: Treat when worms appear and repeat as indicated on the product label. For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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Leaf Spot

Fungal leaf spot diseases are often the cause of early defoliation. Spots are first brown and later grey; leaves yellow and drop.

Treatment

Cultural control: Gathering and destroying infected leaves after they have dropped can be a very effective sanitation method if done thoroughly. If mulch is used, apply fresh mulch after leaf fall.

Chemical control: If leaf spot disease has been a problem in previous years, apply a preventive spray just before blossoms open. If leaf spots still develop, spray again after bloom as indicated on the product label. For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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Powdery Mildew

Powdery mildew is a problem mainly on gooseberry and black currant. The fungus initially appears as a white fluffy mildew that later turns to a brown, felt-like coating on leaves, twigs, and fruits. Hot, humid weather favours the disease.

Treatment

Chemical control: For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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Rust

The rust fungus spends part of its life cycle on white pine, but requires the currant or gooseberry as a host to complete its life cycle. Only the black currant, however, is defoliated. Orange spots, later growing into pimples, appear on the lower surface of leaves.

Treatment

Cultural control: The Consort black currant is resistant to white pine blister rust. Avoid planting currants and white pine near each other.

Chemical control: Spray just before bloom and again after harvest. For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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Scale Insects

Scale insects, particularly San Jose scale, are often found on shoots. The scales are up to 4 mm across, round, with a greyish, nipple-shaped projection in the centre that contain lemon-yellow, sack-like insects.

Treatment

Cultural control: None

Chemical control: Spray thoroughly before leaf buds break. For up to date recommendations on pest management options consult local horticulturalists, Master Gardeners or your local garden supply centres.

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