How do I stop scale on blackcurrants?
Elaine Cope, by email
ANNE SAYS I loathe scale insects. They are such a menace to get rid of on blackcurrants because the adult scales die off over the egg masses underneath, forming a protective lid. Yours are probably woolly vine or currant scale and I expect they make a sticky mess of excreted honeydew and sooty mould. On inspection, 5-7mm-long brown scales and white egg masses coat the stems. I’m afraid the scales are probably still in residence, with overwintering females ready to begin producing more egg masses in May and June. Start by pruning the stems – dispose of them away from the garden. A winter tree wash, based on plant oils, sprayed or wiped on and then repeated next day will help. The first application weakens the scales so the second can take effect. When crawler nymphs hatch in May, use an organic spray suitable for edible plants in a similar way.
Control scale insect infestation on blackcurrants by pruning