Backyard Grapes Identify & treat grapevine problems
Fungal high severity

Esca (trunk disease)

Phaeomoniella / Phaeoacremonium spp.

A chronic wood rot of older vines, showing as "tiger-stripe" leaves and sudden collapse.

Chronic esca 'tiger stripe' leaf symptoms on a mature vine International Wine Challenge (IWC Insight)
Esca leaf symptoms (ESCA Blattsymptom) on grapevine Photo: Bauer Karl Wikimedia Commons CC BY 3.0 AT
Esca tiger-stripe leaf: yellow interveinal bands with green veins (Müller-Thurgau) Photo: Tsui Wikimedia Commons CC BY-SA 4.0
Tiger-stripe esca symptom on a red-variety leaf Photo: Daniele Barbacovi Wikimedia Commons Public domain

Description

Esca is one of a group of grapevine “trunk diseases” caused by fungi that colonise the woody structure through pruning wounds. It is a slow, chronic problem of mature vines rather than a spray-and-fix leaf disease, which makes it frustrating for home growers.

There is no cure once the wood is colonised, so everything centres on prevention: protecting pruning wounds, keeping vines healthy, and cutting out dead wood. Where a trunk is badly affected, training up a fresh sucker to renew the trunk is often the practical fix.

What to look for

  • Yellow or red "tiger-stripe" bands between the veins of older leaves.
  • Dark spotting on berries ("black measles") in some years.
  • Dark streaks and soft, pale rotted wood seen when a trunk is cut.
  • Sudden "apoplexy" — whole arms or vines wilt and die in mid-summer.

Treatment options

Cultural & prevention

Start here — habits that stop problems before they spread.

  • Prune late in dormancy and in dry weather; seal or paint large cuts.
  • Make clean cuts and disinfect tools between vines.
  • Remove and burn dead arms; consider trunk renewal from a healthy sucker.
  • Keep vines unstressed with steady water and balanced nutrition.

Organic / low-toxicity

Gentler sprays and biologicals for active outbreaks.

  • Protect fresh pruning wounds with a biological (e.g. Trichoderma) or wound sealant.

Conventional fungicide / pesticide

For severe cases. Always follow the product label.

  • No reliable curative spray exists — management is preventive and cultural.

Sources

This entry is based on the references below. Read them for full detail and for spray timings and rates valid where you live.

  1. Esca (Black Measles) — UC IPM
  2. Esca — Virginia Tech Grape Pathology Lab (Nita Lab)
  3. Grape (Vitis spp.)-Esca, Young Esca, and Petri Disease — Pacific Northwest Pest Management Handbooks (OSU / WSU / U. Idaho)