FOR THE POTATO SCAB. Soak the uncut tubers for two hours in 30 gallons of water and one pint of formalin (can be secured of any drug-gist). This solution can be used several times. Do not put treated tubers back into crates or bags that held scabby potatoes. Make the treatment only a few days before planting if possible. Do not plant upon land that has recently grown crops of scabby potatoes or beets.
FOR THE BLIGHT AND “BUGS.” Begin spraying with Bordeaux mixture and poison when the “bugs” first appear, or when the plants are about 8 inches high, and repeat about every 2 weeks as long as the plants are growing. Spray often in warm, muggy weather; fewer sprayings are necessary in dry weather.
Use Bordeaux mixture (6 pounds copper sulphate and 4 or 5 pounds of lime to 50 gallons of water, and put in the poison, about 1/2 pound of Paris green or 2 pounds of arsenate of lead, or 1 quart of the stock solution of Kedzie mixture).
Dilute lime-sulphur is not as good as the Bordeaux mixture for potatoes.
WART DISEASE OF THE POTATO. This disease also is known as Black Scab, Canker or Cauliflower Disease. It attacks the tubers mainly. In a severe attack, big, dark warty excrescences sometime as large as the tuber itself appear at the sides or ends. In advanced stages of the disease, the tubers are wholly covered by this growth and lose all resemblance to potatoes. In the final stages, the tubers turn to brownish black soft masses, giving off a very unpleasant odor. In very mild at-tacks, the tubers appear normal, but the eyes are found to have turned gray, then brown and finally black.
This disease is not known to be present in Michigan, but is likely to be found at any time. No remedy is known. When once introduced into a field, the whole crop should be burned and no tuber from the field used for seed purposes. The field itself should not be used for potatoes for at least six or seven years and the disease should be reported together with specimens at the first outbreak or suspicion of outbreak to the Department of Botany, Michigan Agricultural College.
Send specimens in a tight mailing-case.