Garlic (Allium sativum)-Basal Rot


Cause Fusarium culmorum (formerly F. roseum), a fungus. The fungus also can infect elephant garlic but not to the same degree as garlic. Cereals can be infected, but strains usually found on cereals do not infect garlic. Onion is not a host. Soilborne inoculum infects garlic through the stem plate rather than through roots or storage leaves. Infected cloves may not produce disease symptoms but can be a source of the disease. Transmission can occur when infested soil or debris is transported on equipment, seed, or runoff water. Disease expression is erratic from year to year and field to field. Factors affecting disease development are not known.

The disease has been found in Oregon and British Columbia ranging from low incidence to 40% bulb loss. Additional losses can continue during storage.

Symptoms Preemergence decay of cloves and seedlings can occur. Stem plates and storage leaves may decay in the field during the growing season. A reddish fringe to basal rot lesions of actively growing plants may occur but is not diagnostic. Postharvest decay may involve a single clove or the entire bulb.

Cultural control

  • Hot water treatment of symptomless, infected cloves may be useful only if incidence is low.
  • Do not use cereals in rotation with garlic.

Biological control Efficacy in the Pacific Northwest is unknown.

  • Stargus at 6 to 8 fl oz per 1,000 ft row as an in-furrow treatment, or 3 to 4 quarts/A as a soil drench (drip or chemigation) on 10- to 21-day intervals. Preharvest interval is 0 days. 4-hr reentry. O
  • Prestop at 1.4 to 14 oz/10 gal water (0.1% to 1.0% suspension) as a soil drench or incorporation into growing medium. 0-hr reentry. O

Reference Crowe, F.J., et al. 1986. Fusarium basal rot of garlic. Phytopathology 76:1094.