Verticillium Wilt in the Low Desert

HOST: Wide host range, more than 200 species. Most often a problem on vegetables and olive trees

SYMPTOMS:
Herbaceous Plants

• Transitory wilting even when water is available, often on only one side of the plant
• Yellowish areas develop between the veins of older leaves, which then dry, curl and fall off, leaving only the young leaves on the plant.
• Stunting, reduction in growth
• The vascular system is clogged causing the stem to appear streaked.

• Very sudden die back of branch
• Often only one branch affected
• Chronically infected plants can have most of the plant die and still hang on
• Internal discoloration of vascular system between bark and wood. Brown or green streaking (this symptom is not always apparent)

CAUSE:

Soil born pathogen - grows actively in the spring and fall, dormant in the winter and summer. It is most common in irrigated areas since irrigation cools the soil.

MANAGEMENT:
Prevention

• Use resistant varieties - Look for a "V" after the variety name on vegetables. The Swan Hill OliveŽ and other olives grafted on "Oblonga" olive rootstock are resistant.
• Do not plant the same varieties in the same spot year after year - rotate plantings
• Do not overwater or over fertilize
• Remove dead plants

• There is no effective treatment. Remove and destroy infected plants

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