Biosecurity alert: white rot in garlic

White rot of Allium species (caused by Sclerotium cepivorum) has been confirmed in garlic from a Perth backyard and a property in the Swan Valley.

White rot is considered to be the most severe disease of alliums, which include onions, garlic, leeks, shallots and ornamental alliums.

This is the first time the white rot fungus has been detected in WA. This disease is widespread in other states and overseas.

Symptoms

White rot usually affects patches of plants, rather than individuals.

It can be difficult to differentiate from other diseases above ground. The disease is more apparent on the bulb itself.

Growers may first notice stunted plant growth, followed by yellowing and death of the outer leaves. If progressed, remaining leaves and the central stem will die, and there will an obvious rotting of the stem above the bulb. In severe cases the bulb will be completely rotten.

Infected plants will pull easily from the soil. The disease manifests as a fluffy white (mycelia) growth on the roots and root plate, with tiny black growths like poppy seeds (sclerotia).

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During cool weather there may be white, fluffy (mycelia) growth on the infected bulb.

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Close up of poppy seed like growths (sclerotia) on infected garlic

Page last updated: Friday, 28 October 2016 - 12:31pm