Botryosphaeria Canker
One branch or one whole side of a healthy looking shrub browns and dies while the rest carries on, and the dead leaves often stay hanging on the stem like a flag. Peel the bark at the boundary and the wood underneath is stained brown on one side only, with small black pimples erupting through the bark above it.
Disease checklist
Four things to look for. If most of them match what you are holding, you are in the right place.
What gets rid of it
Gentlest option first. For most backyard cases the first one is enough, so try these in order and stop as soon as it works. If you do spray something, the product label tells you how — please read the notice further down.
1Prune well below the stained wood
Cut back until the cross section is clean and white, then cut several inches further, and disinfect the blade between cuts.
isopropyl alcohol spray bottleTry this first2Water deeply in drought
This fungus is opportunistic and takes stressed plants, so soak the root zone in dry spells rather than sprinkling.
soaker hose 50 ft3Mulch, but keep it off the bark
Spread no more than 2 inches of mulch over the root zone and hold it back from the stems.
wood chip mulch bags4Avoid wounding the plant
Keep trimmers away from stems, prune cleanly at the branch collar, and do not prune in wet weather.
bypass pruners garden5Prune blueberries after harvest and in winter
Take out flagged canes at ground level as soon as you spot them, since the wood cannot be healed.
bypass loppers pruning6Plant the right species in the right spot
Do not put drought-sensitive shrubs in hot dry exposed positions, which is what sets up the infection.
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Which plants get botryosphaeria canker
Every plant we cover that gets botryosphaeria canker, grouped by type — tap any one to open its page. A note beside a plant came from that plant’s own entry, because the same disease can be a minor nuisance on one plant and a serious problem on another. Plenty of plants we do not cover get it too.
trees6
Plant families hit hardest
Related plants often share the same problems, so if one plant in a family has it, check the others. The largest group here is Ericaceae, with 3 of the 13 affected plants.
- Ericaceae3 plants
- Cornaceae2 plants
When to treat
There is no effective fungicide, so act by pruning the affected stem out well below the discoloured wood, and treat the underlying cause, which is nearly always drought stress, a wound or winter injury.
Timing only — the label is the law
This page tells you when to watch for botryosphaeria canker and when treating is worth considering. It is not a recommendation to apply any particular product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.
- Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
- Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
- Confirm the product is registered for your crop in your state. This page groups many different crops together, and a product legal on one of them is not legal on all of them — state registrations differ too. Your state pesticide agency or local extension office can confirm both.
- Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.
Other problems on the same plants
If a plant gets botryosphaeria canker, these are the problems it most often gets as well, so they are worth checking for while you are out there. They tend to appear together; one does not cause another.