strong>American Gooseberry Mildew (latin name – Sphaerotheca mors-uvae) is a common fungal disease of gooseberries and blackcurrants. Red and white
currants may also be attacked.
Signs of American Gooseberry Mildew in Gooseberries:
A powdery, white coating appears on new shoots, spreading to young
leaves and, eventually, the berries. Later these patches form a
felt-like mat and turn brown. Leaves curl up and fall off. The
gooseberries are small and may be covered with brown felt.
American Gooseberry Mildew occurs:
* in crowded plants
* humid conditions
* areas of coastal fog
* when the soil around the roots is dry
* where irrigation is by overhead sprinkling
* in crowded plants
Life cycle of American Gooseberry Mildew
The fungus overwinters in dormant buds. These produce infected shoots in
spring which spread the disease by releasing wind-blown spores.
Prevention and control:
* select a suitable planting site which is sunny and not humid
* allow plenty of space between bushes
* prune to keep bushes open and airy
* avoid too much nitrogen-rich fertilizer which will produce soft
shoots, more susceptible to infection
* cut out and burn infected shoots in July & September
* water to keep the soil around the roots moist
* use a mulch
mulch-on-raspberries
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* grow mildew resistant varieties such as Invicta
* chemical control - spray with a sulphur fungicide - but check
that the chemical is safe on the variety by spraying a small area
and waiting for 24 hours to see if the leaves start to curl.
Spray just before flowers open, after fruit set and again 2-3
weeks later. Spray flowering crops at dusk when bees are not
active. Do not use in full sun. Read the label and follow the
instructions.
