Survey Instruction Details:
This survey should only be considered in the states with appropriate climate conditions and suitable hosts for this pathogen: Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, Pennsylvania, Vermont, Virginia, West Virginia, and Wisconsin (see CPHST Pest Datasheet or Solanaceous Hosts manual for more information).
Wart disease can be detected in potato plants from the flowering period to the time of harvest. Inspection at harvest will preclude unnecessary destruction of plants. If a plant is suspected of having wart, a sample of it will be sent to a designated lab (CPHST Beltsville) for confirmation.
This fungus affects the stolons (underground stems) and tubers targeting the meristematic tissue by developing galls/warty growths. Young potato warts are white, soft, and pulpy in texture; the surface is rough and corrugated. Sometimes developing warts can become exposed at or above the soil line.
This disease does not usually present symptoms aboveground; however stems, leaves, and flowers can sometimes develop galls. Attacked plants may show reduced vigor. Small greenish warts may form in the place of aerial buds at stem bases.