# Grape phylloxera

- URL: https://backyardgrapes.com/diseases/phylloxera/
- Scientific name: Daktulosphaira vitifoliae
- Category: Insect / pest
- Affects: Roots, Leaves
- Severity: high
- Favored by: Lives in soil; most damaging to own-rooted Vitis vinifera.
- Easily confused with: Root-knot nematode

**Summary:** A tiny root-feeding aphid-like insect that devastates own-rooted European grapes.

**What to look for:**
- On roots: yellow, hooked swellings (galls) on the root tips that later rot.
- Slow decline — weak growth, small leaves, reduced yield over several years.
- On some varieties: wart-like galls on the leaf undersides.
- Vines on their own roots gradually collapse; grafted vines tolerate feeding.

**Treatment — Cultural / prevention:**
- Plant vines grafted onto resistant American rootstocks — the standard, lasting fix.
- Avoid moving soil, tools, or cuttings from infested sites.
- Remove and replace collapsing own-rooted vines with grafted stock.

**Treatment — Organic / low-toxicity:**
- Sandy soils naturally suppress phylloxera; rootstock choice is the real control.

**Treatment — Conventional (chemical):**
- Soil insecticides are rarely practical or effective for home growers — use rootstocks instead.

Grape phylloxera is a microscopic insect, related to aphids, that feeds on grape
roots. It is the pest that famously devastated Europe's vineyards in the 1800s. Native
American grape species tolerate it, but own-rooted European wine grapes (*Vitis
vinifera*) decline and die.

There is no practical spray cure in the soil. The century-old solution is still the
best one: grow vines **grafted onto resistant rootstock**. If you buy grafted plants,
phylloxera is largely a non-issue; if you grow own-rooted vinifera in phylloxera
country, expect trouble.

**Image credits:**
- Grape phylloxera (Daktulosphaira vitifoliae) galls on the underside of a Vitis leaf, Montgomery County, Pennsylvania — [Photo: Beatriz Moisset, Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Daktulosphaira_vitifoliae._closeup.jpg) (CC BY-SA 4.0)
- Bumpy growths (grape phylloxera galls) on the underside of a new grape leaf — [SDSU Extension](https://extension.sdstate.edu/phylloxera-grape-pest)

**Sources:**
- [Grape Phylloxera: Biology and Management in the Pacific Northwest (EC 1463)](https://extension.oregonstate.edu/catalog/pub/ec-1463-grape-phylloxera-biology-management-pacific-northwest) — Oregon State University Extension
- [Grape Phylloxera - Grape Pest Management Guidelines](https://ipm.ucanr.edu/agriculture/grape/grape-phylloxera/) — UC IPM
- [Grape - Grape Phylloxera](https://pnwhandbooks.org/insect/small-fruit/grape/grape-grape-phylloxera) — Pacific Northwest Pest Management Handbooks (OSU / WSU / Univ. of Idaho)
- [Phylloxera: A Grape Pest](https://extension.sdstate.edu/phylloxera-grape-pest) — South Dakota State University Extension