Blackcurrant: sticky leaves, or a sticky surface below the plant

What it is likely to be on blackcurrant

1. Aphids

   Candidate 1very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Aphids
   • Royal Horticultural Society: Fruit — aphid damage

   Checked 2026-08-13

   Sap-feeding insects that cluster on soft growing tips and leaf undersides, distorting new growth and leaving sticky honeydew that blackens with sooty mould. Most garden infestations are transient and end when predators catch up.

   Points towards it

   • · honeydew is sugar passed through a sap-feeder's gut, so its presence proves one is feeding even when the colony has already gone
   • · aphids feed where the sap is richest and the tissue softest, which is the shoot tip and the youngest leaves
   • · spring outdoors and any time under glass both suit them

   Argues against it

   • · mites make webbing and do not produce honeydew at all, so a sticky plant is not a mite problem — this rules it out entirely.
   • · waxy wool packed into leaf joints is mealybug or woolly aphid, which is a different treatment and a different place to look

   Check this next

   Turn over the youngest leaves at a shoot tip and look for ants. Fruit aphids pack the growing points and the undersides of the newest leaves in dense colonies of green, black or pink insects, and ants patrolling up and down the stems are farming them for the honeydew — that combination settles it in seconds. The sticky film ends up on the leaves and fruit below the colony rather than on the colony itself, and a black sooty mould grows on it afterwards, which is a consequence rather than a second problem. On currants, check whether the leaves above are also puckered and blistered red: that is a specific aphid with a specific answer.

   What to do now

   Tolerate a light infestation on an established fruit tree or bush, because ladybird, hoverfly and lacewing larvae arrive within a couple of weeks and deal with it, and spraying kills them along with the aphids. Where it is heavy on a young plant, squash the colonies between finger and thumb or dislodge them with a jet of water, and pinch out the worst-infested shoot tips. Wash sooty mould off fruit before eating. On a wall-trained peach or a greenhouse melon, check weekly from early spring, since populations build far faster under cover with no predators.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Aphids — control

   Checked 2026-08-13

2. Currant blister aphid

   Candidate 2very common on this plant

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Currant blister aphid
   • Agriculture and Horticulture Development Board — AHDB: Ribes — aphid pests

   Checked 2026-08-13

   Raised puckered blisters on currant leaves — crimson on redcurrant and whitecurrant, yellow-green on blackcurrant — with pale aphids sheltering on the undersides. It looks alarming and like a disease, and it is neither: the aphids leave for other plants by midsummer, the fruit is unaffected, and the blistered leaves stay blistered because the damage was done while they were expanding.

   Points towards it

   • · the leaf above the colony puckers into raised blisters, red on red and white currants and yellow-green on blackcurrant
   • · it attacks the expanding leaves at the shoot tips in spring
   • · it is a sap-feeder and leaves honeydew like any other

   Argues against it

   • · blistering is caused as the leaf expands, so fully hardened old leaves do not develop it afresh

   Check this next

   Look at the shape of the leaf, then turn it over. Blister aphid raises the leaf into puckered domed blisters — vividly red on redcurrant and whitecurrant, yellow-green on blackcurrant — and the pale aphids are underneath, directly below each blister. That raised, painted-looking distortion is unlike any other currant problem: ordinary aphids curl a leaf without blistering it, and a virus mottles without raising the surface. The colour alarms people far more than the damage warrants.

   What to do now

   Usually nothing. The aphids leave for their summer hosts by midsummer, the blistered leaves stay disfigured but keep working, and the crop is essentially unaffected — this is one of the few pests where the honest answer is that it looks much worse than it is. On a young bush where damage is heavy, squash the colonies on the leaf undersides in spring or pinch out the worst tips. Do not spray a cropping bush for a cosmetic problem.

   ·source

   Sourced guidancehigh confidence

   • Royal Horticultural Society: Currant blister aphid — control

   Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on blackcurrant — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general sticky leaves, or a sticky surface below the plant page lists causes across all plants, and the Blackcurrant profile lists the problems it is prone to.