---
title: Pythium
canonical: https://fernland.com.au/problem-solver/pythium/
dateModified: 2026-08-07 09:59:37
summary: "Pythium is a soil- and water-borne pathogen causing damping-off and root rot in seedlings, turf and nursery stock, especially in wet, poorly drained conditions."
type: article
keywords: [Pythium, Pythium spp.]
---

# Pythium

> Pythium is a soil- and water-borne pathogen causing damping-off and root rot in seedlings, turf and nursery stock, especially in wet, poorly drained conditions.

*Pythium spp.*

Pythium is a genus of oomycetes, sometimes called water moulds, that behave like fungi in causing plant disease. They are common soil and water inhabitants in Australian nurseries, turf and landscape settings, and can persist for long periods as resistant spores in soil, growing media, water storage systems and plant debris.

Disease is most severe where conditions are wet and poorly drained, including waterlogged soils, overwatered pots, compacted turf, and recirculated irrigation water. Pythium is spread by moving water, contaminated media, tools, pots and plant material, and can move rapidly through irrigation systems once established. It affects a wide host range, including turf grasses (as Pythium blight or root rot), seedlings and cuttings (damping-off), and container and field-grown nursery stock (root and crown rot).

Management relies on cultural and hygiene practices rather than curative treatment alone. Improving drainage, avoiding overwatering, ensuring free air movement, using clean pathogen-free water sources, and sanitising pots, benches and tools between crops all reduce disease pressure. Media should be well-drained and, where possible, pasteurised or sourced from suppliers with good quality control. In turf, reducing thatch, improving surface and subsurface drainage, and avoiding excess nitrogen during warm, humid weather help limit outbreaks. Fungicide options exist and are best used as part of an integrated program alongside these cultural controls, applied preventatively in high-risk periods rather than after severe symptoms appear.

## How to identify

- Damping-off of seedlings: collapse and rotting of stems at or below the soil line, often before or shortly after emergence
- Water-soaked, dark or blackened roots that are soft and easily sloughed off, leaving a stringy core
- Stunted, wilted or yellowing plants despite adequate soil moisture, due to root loss
- In turf, irregular patches of blighted or greasy-looking grass, often in low-lying or poorly drained areas, most active in warm, wet, humid weather
- Rapid spread following heavy rain, flooding or extended leaf/soil wetness
- Poor establishment or patchy stands in newly seeded or sprigged turf and nursery beds

## Registered products we stock

- [Banrot 400WP Fungicide](https://fernland.com.au/banrot-400wp-fungicide/) — ICL
- [Heritage Maxx Turf Fungicide](https://fernland.com.au/heritage-maxx-turf-fungicide/) — Syngenta
- [Proplant Systemic Fungicide](https://fernland.com.au/proplant-systemic-fungicide/) — Colin Campbell Chemicals
- [Azoxystrobin 250SC Fungicide](https://fernland.com.au/azoxystrobin-250sc-fungicide/) — EnviroMax
- [Subdue Maxx Turf Fungicide](https://fernland.com.au/subdue-maxx-turf-fungicide/) — Syngenta
- [Liquid Thiram Fungicide](https://fernland.com.au/liquid-thiram-fungicide/) — Amgrow Specialty Agriculture
- [Quali-Pro Evolution Advance | Fungicide](https://fernland.com.au/quali-pro-evolution-advance-fungicide/) — Adama
- [Emerald Turf Fungicide](https://fernland.com.au/emerald-turf-fungicide/) — Colin Campbell Chemicals
- [Headway Maxx Turf Fungicide](https://fernland.com.au/headway-maxx-turf-fungicide/) — Syngenta
- [Banrot 80G Fungicide](https://fernland.com.au/banrot-80g-fungicide/) — ICL
- [Lexicon Intrinsic | Fungicide](https://fernland.com.au/lexicon-intrinsic-fungicide/) — BASF
- [Magellan 800WG Systemic Fungicide](https://fernland.com.au/magellan-800wg-systemic-fungicide/) — Adama
- [Chino 400SC | Turf Fungicide](https://fernland.com.au/chino-400sc-turf-fungicide/) — Colin Campbell Chemicals
- [Signature Xtra Stressgard | Systemic Turf Fungicide](https://fernland.com.au/signature-xtra-stressgard-systemic-turf-fungicide/) — Envu

## Image credits

- [Photo: Dr. phil. Gerhard Bedlan, Wien, Österreich. via Wikimedia Commons (CC BY-SA 4.0)](https://commons.wikimedia.org/wiki/File:Petersilie_Globisporangium_mastophorum_1_-_Bedlan_Gerhard,_Dr._phil._Wien.jpg)
- [Photo: Howard F. Schwartz, Colorado State University, Bugwood.org via Wikimedia Commons (CC BY 3.0 us)](https://commons.wikimedia.org/wiki/File:Pythium_5361373.jpg)
- [Photo: Dr. phil. Gerhard Bedlan, Wien, Österreich. via Wikimedia Commons (CC BY-SA 4.0)](https://commons.wikimedia.org/wiki/File:Petersilie_Globisporangium_mastophorum_2_-_Bedlan_Gerhard,_Dr._phil._Wien.jpg)
- [Photo: Roswitha Ulrich, Pflanzenschutzdienst via Wikimedia Commons (CC BY-SA 4.0)](https://commons.wikimedia.org/wiki/File:Basilikum_Pythium-1--Roswitha_Ulrich.jpg)