# Grapevine leafroll

- URL: https://backyardgrapes.com/diseases/leafroll-virus/
- Scientific name: Grapevine leafroll-associated virus (GLRaV)
- Category: Viral
- Affects: Leaves
- Severity: moderate
- Favored by: Spread by infected planting material and by mealybug/scale insects.
- Easily confused with: Pierce's disease, Esca (trunk disease), Grapevine red blotch, Grapevine fanleaf virus, Potassium deficiency, Magnesium deficiency

**Summary:** Autumn leaves that roll downward and turn deep red or yellow while the veins stay green.

**What to look for:**
- Leaves cup and roll downward at the edges, especially later in the season.
- Reds/purples in dark varieties, or yellowing in white varieties, between the veins.
- The main veins stay noticeably green against the coloured leaf.
- Delayed ripening, poor colour, and lower sugar in the fruit.

**Treatment — Cultural / prevention:**
- Start with certified virus-tested planting stock — this is the main defence.
- Remove and replace confirmed infected vines to limit spread.
- Control mealybugs and soft scale, which move the virus vine-to-vine.

**Treatment — Organic / low-toxicity:**
- Manage mealybug/scale with horticultural oil and by supporting natural predators.

**Treatment — Conventional (chemical):**
- No cure for the virus itself; insecticides target the insect vectors only.

Grapevine leafroll is a viral disease (a complex of several related viruses) that
cannot be cured — an infected vine stays infected for life. Its autumn display is
striking and easy to recognise: leaves roll under and colour up brightly while the
veins remain green.

The virus travels two ways: inside infected cuttings and nursery plants, and between
vines on mealybugs and scale insects. For a home grower, the whole game is
prevention — buy clean stock, and keep the insect vectors in check so a single
infected vine doesn't seed the rest of the row.

**Image credits:**
- Reddened, downward-rolling leaves of a red grape variety infected with grapevine leafroll disease — [Plantix](https://plantix.net/en/library/plant-diseases/200030/grapevine-leafroll/)
- Grapevine leafroll disease: red, downward-cupped leaves with veins remaining green — [Photo: Ed Hellman, Texas AgriLife Extension, California Department of Food and Agriculture, PD/GWSS Board](https://www.cdfa.ca.gov/pdcp/board/grapevineleafrolldisease.html)
- Red-variety grapevines with leafroll: leaves roll downwards and turn intense red long before autumn — [Photo: Roderick Bonfiglioli (private collection), Te Ara – the Encyclopedia of New Zealand](https://teara.govt.nz/en/photograph/18322/grapevine-leafroll-symptoms)

**Sources:**
- [Grapevine Leafroll Disease](https://pubs.extension.wsu.edu/grapevine-leafroll-disease) — Washington State University Extension
- [Virus Diseases - Grape Pest Management Guidelines](https://ipm.ucanr.edu/agriculture/grape/virus-diseases/) — UC IPM
- [Red Leaves in the Vineyard: Biotic and Abiotic Causes (FS1260)](https://njaes.rutgers.edu/fs1260/) — Rutgers NJAES Cooperative Extension
- [Ecology and Management of Grapevine Leafroll Disease](https://www.frontiersin.org/articles/10.3389/fmicb.2013.00094/full) — Frontiers in Microbiology (2013)