Botrytis Bunch Rot

Botrytis bunch rot is gray fuzz and slip-skin on a tight Himrod cluster near harvest. It is the same fungus as gray mold on peony — this job is the bunch. Vinegar without fuzz is sour rot leftover. A spray will not rewind a tight cluster. Walk the shady side after rain. Fail if you wait until the whole bunch is slime. Open the fruit zone tonight.

Do this first: pull the bunch apart, bag the mush, and open the fruit zone. Fail if you judge from the pretty face. Two wet nights after the berries color will finish a tight cluster. Water the soil. Keep the fruit dry at bedtime. Vinegar without fuzz is leftover. Hard raisins in June are black rot.

Gray fuzz on the bunch, or sour vinegar

Walk the cluster. Do not judge from the pretty face. A tight Himrod bunch against a wall holds night wetness even when noon looks dry. Fail if you only scout from the path. Two minutes inside the cluster beat a harvest funeral. Pull a few berries apart after rain. Gray fuzz and slip-skin are this job. Vinegar without fuzz is leftover. Hard raisins in June are black rot.

Slip-skin after harvest rain

Pull the bunch apart. The skin slides off the flesh. Gray fuzz follows wet, still air. Walk the shady side after rain. Fail if you judge from the pretty face of the cluster. Two or three days of wet harvest weather can turn a tight bunch. Scout twice a week after the berries color. Smell inside the cluster. Musty gray is this job. Vinegar is leftover. Fail if you wait until the whole bunch is slime. A tight Himrod cluster against a fence holds night humidity even when the day looks dry. Open a path for air before the next rain.

Same fungus as peony — this job is the cluster

Peony blight stays with gray mold. This job is the grape bunch. Fail if you copper a peony mix onto Himrod and skip the fruit zone. Two to three open leaves around the cluster beat a shelf bottle. A fuzzy peony bloom in May is not tonight’s Himrod cluster. Walk the fruit, not the flower bed. Fail if you treat every Botrytis as one spray. The cluster needs air first. The peony needs a bag over the bloom first. Two jobs, two cleanups.

Open the fruit zone

Pull a few leaves so air moves through the bunch. Fail if you strip every leaf in one hot afternoon and scald the berries. Water the soil. Stop evening overhead. A dry cluster at bedtime is worth more than a bottle. Two leaves on the east side can stay; pull the ones that trap wet air on the west. Fail if you leaf-pull in noon heat after a drought week. Work in the morning. A backyard arbor still needs a gap around the fruit. Do not copper a closed canopy and call it done.

A spray will not rewind a tight cluster

A rotting berry does not unkink. Wait while only a few berries are gone. Act on the mush tonight. Fail if you copper a collapsing cluster or leave it as next year’s trash. Skip the brand aisle. Two wet nights after the berries color will finish a tight bunch. Fail if you wait for a farm spray chart. Open the fruit zone first. Bag the mush. Water the soil. A late bottle on a closed canopy is theatre. Copper is slight leftover — not the plan.

Tight clusters after veraison

Tight fruit holds humidity. After the berries color they open to this fungus. Fail if you wait for a Pinot row that is not in this bed. Himrod still packs a tight bunch in a wet August. Thin a cluster that is jammed against the wire. Fail if you leave flowering trash stuck in the bunch — that trash feeds early infections. Two minutes of shaking out cap leftovers after bloom beat a harvest funeral. Keep birds from pecking holes that this fungus uses as a door.

Not a hard mummy

Hard raisins in June are black rot. This job is soft and gray near harvest. Fail if you treat a summer mummy as slip-skin. Pull the bunch apart. A hard blue-black raisin still hanging in July is the other job — pull the trellis. Gray slime in August is this job — bag the mush and open the fruit zone. Two diseases can sit on one Himrod. Do not copper both as one leftover.

Do not compost the mush

Bag rotten clusters and old bunch trash. The fungus winters there. Fail if last year’s trash stays in the compost under this year’s bloom. Two minutes of bagging beats a July explosion. Winter prune old stems out of the wires. Fail if you leave mummified gray bunches as next year’s starter. A home vine that never gets a cleanup will slip-skin the same clusters every wet harvest. Keep the pile off the garden. Do not feed the compost.

Open the fruit zone — a bottle will not rewind slip-skin

1. Confirm gray fuzz and slip-skin. Vinegar without fuzz is sour rot leftover. Pull the bunch apart. Fail if you judge from the pretty face.
2. Bag the mush. Do not compost. Last year’s trash under this year’s bloom is next year’s starter. Fail if gray bunches stay in the wires all winter.
3. Open a few leaves around the fruit. Two leaves on the morning side can stay. Pull the ones that trap wet air. Fail if you strip every leaf in noon heat after a drought week.
4. Water the soil in the morning. Stay off the clusters. A dry bunch at bedtime beats a late bottle. Fail if evening overhead hits a tight cluster after the berries color.
5. Skip the bottle as the plan. Fail if copper replaces air. Two wet nights in a tight cluster finish the job. Keep last year’s trash out of the wires. A closed canopy plus harvest rain is this walk.

Related reading

• Gray mold or Botrytis — peony blooms, same fungus, different job.
• Black rot — hard mummies, not slip-skin.
• Phomopsis cane and leaf spot — May cane cracks.
• Powdery mildew — white powder that can wound berries and open this job.