How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Vines infected with Armillaria root rot usually completely collapse. Occasionally, white mycelial mats can be found under the bark at the soil line, but more commonly white mycelial strands are seen interwoven through darkened cortical tissue. Dark, rootlike structures called rhizomorphs grow from the root into the soil after symptoms develop on vines.

COMMENTS ON THE DISEASE

The fungus survives on diseased wood and roots belowground for many years. Healthy plant roots can become infected when they come in contact with inoculum from a preceding orchard crop or nearby oak trees. Although kiwifruit plants are somewhat tolerant of this fungus, if the vine has already been weakened by Phytophthora infection, its death may be hastened by an invasion of A. mellea. Flood waters sometimes spread infected roots in a vineyard. The fungus is favored by soil that is continually damp. Although the pathogen produces mushrooms, they are not considered significant in disease spread.

MANAGEMENT

When clearing land for planting or replanting vines, carefully remove and burn roots 1 inch or greater in diameter.

PUBLICATION

UC IPM Pest Management Guidelines: Kiwifruit
UC ANR Publication 3449
Diseases
J. E. Adaskaveg, Plant Pathology, UC Riverside
T. J. Michailides, Plant Pathology, Kearney Ag. Center, Parlier
W. D. Gubler, Plant Pathology, UC Davis
Acknowledgment for contributions to Diseases:
C. Arredondo, Plant Pathology student, UC Davis
K. Conn, Plant Pathology, UC Davis

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