🐛✗ Tested and false“Big bud mite also attacks gooseberries and redcurrants, so they need the same winter bud check as blackcurrants”
Cecidophyopsis ribis is host-specific to blackcurrant. Neither the RHS nor the James Hutton Institute list gooseberries, redcurrants or whitecurrants among the plants it colonises, and both treat it strictly as a blackcurrant pest. The confusion likely comes from gooseberry's supporting role in breeding: the resistance gene bred into Ben Hope originally came from a wild gooseberry relative, which is a genetic link, not a sign the mite itself spreads to gooseberry bushes.
What to do: Give blackcurrants their winter bud check for swollen, rounded buds, but there is no need to inspect gooseberries or redcurrants for this particular mite.
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“Ben Hope blackcurrants are immune to big bud mite, so an infested Ben Hope bush must be something else”
Ben Hope is resistant, not immune. The James Hutton Institute quantifies its reduced susceptibility at roughly 40 times lower than older varieties, a large improvement but not zero risk, and the RHS itself calls it a mite-resistant cultivar rather than a mite-proof one. A Ben Hope bush can still develop swollen buds, just far less readily than an unimproved variety.
What to do: Still check Ben Hope bushes for swollen buds in winter. Resistance lowers the odds of colonisation, it does not remove them.
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“Spraying an insecticide or miticide is the way to control big bud mite in a home garden”
No chemical control is recommended for home gardeners against this mite. Hand removal, certified stock and resistant varieties are the measures given for amateur growers, with no spray listed, and separately, the number of acaricides even approved for commercial control of the mite is shrinking. That combination points away from spraying as a realistic home option, not just an unrecommended one.
What to do: Rely on winter bud removal, certified planting stock and a resistant variety such as Ben Hope rather than looking for a spray product.
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“Spotting a few swollen big bud mite buds means the whole bush is doomed and should be dug up straight away”
A light infestation is explicitly tolerable. Affected plants can continue to crop well for several years, so some presence of the mite can be lived with, and cropping and vigour only really suffer once populations build up to large numbers. Digging up a bush over a handful of swollen buds skips past the management options, hand removal, certified replacement stock and resistant varieties, that are meant for exactly this stage.
What to do: On a bush with only a few swollen buds, pick them off over winter and keep monitoring rather than removing the plant. Reserve digging up and replanting for a bush that is heavily infested.
In Scotland: Because reversion virus, the more serious long-term threat this mite carries, does not show up in the leaves until well after infection, the swollen buds are the earlier and more useful warning sign, which is another reason to manage a light infestation rather than jump straight to removal.
1 source
- RHS, Blackcurrant big bud miteStates that affected plants can continue to crop well for several years and that some presence of the mite can be tolerated, with cropping and vigour only suffering once populations build up to large numbers.
“Picking off the swollen buds in winter gets rid of big bud mite for good”
Hand removal works as ongoing management on a lightly affected bush, not as a one-off cure. Picking off and disposing of affected buds during winter is recommended specifically for lightly affected plants, as a way to stop a small problem building into a large one. For a heavily infested bush, guidance moves past hand removal entirely and recommends letting it finish one last harvest before digging it out and replanting with certified stock, which only makes sense if picking buds off a badly infested bush is no longer considered effective.
Our read Framed as a binary cure-or-fail question, this is disputed rather than clearly busted, because hand removal is never claimed to eradicate the mite even on light infestations, only that it holds the population down. Whether that counts as "getting rid of it" depends on how thoroughly a gardener does the job every winter.
What to do: Treat winter bud removal as annual maintenance on a lightly infested bush, not a single fix. Once a bush is heavily affected, plan to remove and replace it with certified stock rather than continuing to hand-pick.
1 source
- RHS, Blackcurrant big bud miteRecommends picking off and disposing of affected buds during winter on lightly affected plants, and recommends removing and replanting heavily affected bushes rather than hand-picking them.
