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).