Department of Botany and Entomology
During the seasons of 1894 and 1895 a series of experiments on the treatment of potato scab were carried out at the station farm. There were two primary objects in conducting these experiments: first, to test the practicability of certain methods of treatment, particularly in land already infested with scab; second, to test the power of the various varieties to resist the disease, and also their behavior toward certain fungicides. The fungicides used were corrosive sublimate (bichloride of mercury), bordeaux mixture and eau celeste. The seed was treated by immersion before cutting and by spraying after being dropped into the furrow. In one series of plats the land was known to be infested with scab, having been planted to potatoes for at least five consecutive seasons and producing a crop more or less badly scabbed. In the other series the land had never been planted to potatoes and was therefore supposedly free from the fungus producing the scab. The season of 1894 was so dry that the conditions were very unfavorable for the development, either of the potatoes or of the scab-fungus. As a result the yield was very light, and, with but few exceptions very little scab was found, even in the infested land. The difference between treated and untreated plats was not very marked, what there was being in favor of the former. The experiments of the past season were much more satisfactory and show some very interesting facts. The tables which follow give the results of the experiments on infested ground.
potato scab, twig gall moth, saw fly, wheat stem maggot
South Dakota Agricultural College and Experiment Station
Williams, T.A., "Potato Scab. Three Injurious Insects" (1896). Agricultural Experiment Station Bulletins. 48.