Control
Non-chemical control
A number of measures will help reduce the occurrence of the disease;
- Gooseberries are best pruned to an open form to aid picking, and this also discourages stagnant air amongst the branches and promotes the circulation of air
- Avoid planting in low-lying or enclosed areas or with poor air flow
- Opening up bushes will also greatly ease picking and control of gooseberry sawfly
- Avoid excessive quantities of nitrogen rich manure (dried poultry manure pellets for example) or mulching with manure, because the resulting soft growth is more readily attacked
- A dressing of a balanced fertiliser, such as Growmore, is more suitable – use 50g per sq m (1½oz per sq yd)
- The fungus overwinters within the buds and on the shoots, and (with blackcurrants in particular) on fallen leaves. It is therefore essential to ‘tip’ prune the bushes by removing and disposing of (bonfire or shredding and composting) the ends of affected shoots as soon as they are seen, as well as disposing of all fallen leaves in autumn
Resistant cultivars
Resistant cultivars are available and offer a useful level of resistance to this disease:
Gooseberry cultivars:
‘Captivator’: Resistant
'Greenfinch' AGM: Resistant
‘Hinnomaki Gold’: Slightly Resistant
‘Hinnomaki Red’: Resistant
‘Hinnomaki Green’: Resistant
'Invincta' AGM: Resistant (Although young plants of this variety show moderate attacks of mildew the shoots of mature plants and fruits are highly resistant)
‘Martlet’: Resistant
‘Pax’: Slightly Resistant
‘Remarka’: Resistant
‘Rokula’: Resistant
Blackcurrant cultivars:
‘Ben Alder’: Slightly Resistant
‘Ben Connan’ AGM: Resistant
‘Ben Gairn’: Resistant (Also resistant to reversion virus)
‘Ben Hope’: Resistant (Also resistant to gall mite)
‘Ben Lomond’ AGM: Slightly Resistant
‘Ben More’: Resistant
‘Ben Sarek’ AGM: Resistant
‘Ben Tirran’: Resistant
‘Big Ben’: Resistant
To source plants use: RHS Find a Plant
Chemical control
SB Plant Invigorator, Resolva Natural Power Bug and Mildew Control, RHS Bug and Mildew Control, Ecofective Bug & Mildew Control and the Ecofective ‘Defender’ range contain a blend of surfactants and nutrients and can be used on any edible or ornamental plants, with no harvest interval. They have a physical mode of action and may be used against powdery mildews, as well as a range of pests such as whiteflies, aphids, spider mites, mealybugs, scale insects and psyllids.
Inclusion of a product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home gardener.
Download
Fungicides for gardeners (Adobe Acrobat pdf document outlining fungicides available to gardeners)
Links
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: storing and disposing safely