[Digger Dan]

Anyone know what this leaf infection is on a blackcurrant bush?
On the underside of the leaf I have noticed what appear to be green aphids. Are they the cause of the problem?



It first appeared last year. I pinched out the infected leaves and still had an excellent crop of currants. This year I don't think I'll be so luckly so I think I'll need to take some chemical action?

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Digger Dan

[James Kilkelly]

Nice shot, sorry about the damage Digger Dan.
Looks like currant blister aphid those little sap suckers.
Not the end of the world and they seldom cause the failure of the crop as after mid-summer they grow wings and fly off.
However to control......
Spraying with garden centre bought fatty acids is quite effective if applied every 5-7 days on both the upper and lower sides of the leaves.
You can also spray with pyrethrum or derris on a similar timescale to the fatty acid.
If spraying, do so at dusk to avoid damage to pollinating insects.

[Digger Dan]

You were right GPI looks like that little aphid didn't cause too much damage.

Good crop of fruit, harvested 2.0KG of blackcurrants already to make 10 pots of jam. There's probably another 2.0KG still ripening on the bush. Maybe I'll make Ribena this time unless anyone has a better idea what to do with blackcurrents!



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DiggerDan

[michael brenock]

yes it is aphid damage blackcurrant leaf blister aphid. Control by fingers when spotted earlier in year when numbers are small and before they spread, they don't do a great deal of harm but will recur next year if you don't take control measures.
michael brenock horticultural advisor (retired)