Verticillium wilt

Infected leaves
Verticillium wilt: close-up view of yellow leaves with green veins and water-soaked margins
Infected and healthy plants
Plant stunted by verticillium wilt
Cause

Verticillium dahliae

Damage

Minor overall, but can be serious on some farms in some seasons. Often occurs on crops grown on the best soils in the South Burnett and in irrigated crops in low rainfall areas. Infection before early podfill may reduce yield, but the impact is small if leaf symptoms appear after this time.

Symptoms

Pale green blotches appear between the veins and around the leaf margins. The margins then become brown and die. Under dry conditions these areas dry out, giving the plant a scorched appearance. The vascular tissues in stems and roots are discoloured reddish-brown. Wilting and plant death sometimes occur.

Spread

Hosts include the weeds cobbler's pegs, noogoora burr and anoda weed and many crop plants.

Management options

Once infection occurs, nothing can be done to control verticillium wilt.

Cultural
Remove weed hosts and infected crop residues. Making hay may be warranted if large amounts of fungal inoculum is present in the leaves and stems throughout the paddock. Dig the crop as early as possible.

Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority chemical database and permit database for chemicals registered or approved under permit to treat this disease on the target crop in your state or location. Always read the label and observe withholding periods.