Garlic Rot

Garlic rot matters because infected seed cloves are a primary inoculum source: planting one symptomatic or latent clove can start a patch that persists in soil for years. If you've grown garlic repeatedly in the same bed or you bought untested seed, disease pressure rises; growers with a history of garlic losses should assume the bed is risky and act accordingly. For practical seed selection and sourcing, choose certified or tested stock and avoid planting cloves from bulbs that showed any basal discoloration the previous season.

Two pathogens dominate home gardens. White rot (Sclerotium cepivorum) produces a white, cottony mycelium and small black sclerotia that survive long-term in soil; it prefers cool, moist soils and will wipe out beds over multiple seasons. Basal rot (Fusarium oxysporum f. sp. ceporum) causes yellowing foliage, brown or dry decay at the bulb base, and often stresses bulbs so they fail to store. Bacterial soft rot shows wet, smelly decay and moves fast in warm, saturated conditions.

Transmission routes are straightforward: infected seed garlic, contaminated tools, and infested soil move the pathogens. White rot sclerotia can persist for many years, so simply planting a different allium in the same bed soon after infection can re-establish disease. If seed selection and sanitation are neglected, the problem compounds and becomes much harder to manage with a single season of action. Consider the bed's disease history before replanting garlic or onions; long rotations are often the only reliable way to reduce inoculum to low risk levels.