Verticillium wilt—Verticillium dahliae
Verticillium wilt infections in almonds usually become apparent when leaves on one or more branches suddenly
wilt, turn light tan, and die. Dead leaves generally remain on the tree throughout the growing season.
Internally, the vascular tissue tissue turns dark, and cross sections of the branch will show a full or
partial ring of discolored tissue.
Life cycle
Solutions
Verticillium wilt can be avoided in many cases by planting
resistant or tolerant varieties or rootstocks. The Verticillium fungus
has a wide host range, including tomatoes, cucurbits, caneberries,
and stone fruit. Keeping these susceptible crops out of
garden areas for 3to 5 years can reduce Verticillium
to levels where a crop can be profitably grown for 1 or 2
years. Corn, other grains, carrots, lettuce, beans, and
peas are some crops that could be used. Soil
solarization during a summer fallow period before planting may help reduce
disease levels. Proper fertilization and irrigation will
help young trees recover from the fungus. Prune out all
weakened and dead limbs in midsummer when the fungus is no
longer active. | 
Almond
tree affected by Verticillium wilt
Cross
section of almond branch
|
