Backyard Grapes Identify & treat grapevine problems
Fungal high severity

Botryosphaeria dieback

Botryosphaeriaceae (Neofusicoccum, Diplodia, Lasiodiplodia)

A trunk-disease complex that cankers cordons and kills spurs, closely mimicking Eutypa.

Symptoms on a mature grapevine infected with Botryosphaeria dothidea: stunted growth and shoot dieback (a, b), wedge-shaped wood necrosis (c), bud necrosis (d), cane bleaching (e), shoot dieback (f) and leaf chlorosis (g) Photo: M. Arzanlou, S. Moshari, M. Bakhshi and S. Khodaie (Australasian Plant Disease Notes, 2012) Australasian Plant Disease Notes (Springer)
Typical Botryosphaeria dieback symptoms on sampled grapevines: apoplexy (a, b) and internal wood necroses (c-g) Photo: Milan Spetik, Dorota Anna Tekielska, Akila Berraf-Tebbal, Jakub Pecenka, Katerina Stuskova, Alla Eddine Mahamedi and Ales Eichmeier (Diversity, 2023) MDPI Diversity CC BY 4.0
Symptoms of grapevine Botryosphaeria dieback in China: fruit dropping (a), bagged clusters with almost all fruit dropped (b), vine canker (c), cob canker (d) and vine death (e) Photo: Ji-Ye Yan et al. (Fungal Diversity, 2013) Fungal Diversity (Springer)

Description

Botryosphaeria dieback is caused by a family of fungi (the Botryosphaeriaceae, including Neofusicoccum and Diplodia) rather than a single species. Like Eutypa, they enter through pruning wounds and build cankers in the permanent wood, so the two are often lumped together as “trunk diseases” and are hard to tell apart without lab work.

For a home grower the distinction matters less than the response, which is the same for both: dry-weather pruning, cutting losses back into clean wood, retraining from healthy suckers, and protecting large cuts. Warm, wet climates see the most damage. If several old vines show dead spurs and wedge-shaped cankers, assume a trunk-disease complex and manage the whole planting for it.

What to look for

  • Dead spurs and patchy, uneven bud break in spring.
  • Wedge-shaped internal wood cankers, usually centred on old pruning wounds.
  • Cordon and arm dieback that spreads a little further each season.
  • Bleached, dead bark on affected arms.

Treatment options

Cultural & prevention

Start here — habits that stop problems before they spread.

  • Prune during dry weather, ideally late dormancy, to limit wound infection.
  • Remove dead spurs and cankered wood, cutting back into healthy tissue.
  • Retrain trunks or cordons from clean growth when an arm is lost.
  • Seal large pruning wounds.

Organic / low-toxicity

Gentler sprays and biologicals for active outbreaks.

  • No curative treatment exists — rely on sanitation and wound protection.

Conventional fungicide / pesticide

For severe cases. Always follow the product label.

  • Protectant fungicides on fresh pruning wounds where labelled.

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. Botryosphaeria Dieback / Grape / Agriculture: Pest Management Guidelines — UC Statewide IPM Program (UC ANR)
  2. Grape (Vitis spp.) - Botryosphaeria Dieback — Pacific Northwest Pest Management Handbooks (Oregon State, Washington State, Univ. of Idaho)
  3. Grapevine trunk disease: Best practice management guide (Version 2.1, June 2021) — Wine Australia / SARDI
  4. Practical management of grapevine trunk diseases — Wine Australia