Pinedale Roundup

Disease Has Been Cause of Serious Losses.

In view of the great tendency of scab to appear when the soil is alkaline, Dr. W. H. Martin, specialist in potato diseases at the New Jersey State College of Agriculture, suggests that the potato grower exercise caution in the use of alkaline materials such as lime and nitrate of soda.

Potato scab has long been the cause of serious losses to the potato growers of the state. Although this disease was less severe than usual during the past season, few fields were observed to be entirely free from it. Many fields were observed where as much as 90 per cent of the crop was so scabby as to be unsalable. It is recognized that scab is usually most severe on an alkaline soil and that as the soil acidity is increased the severity of the scab attack decreases.

One instance was noticed recently by the potato specialist, where all of the nitrogen in a complete fertilizer was derived from nitrate of soda, with the result that a large portion of the crop was so scabby as to be unsalable. On this same farm, on land where sulphate of ammonia was used as a source of nitrogen, a considerable reduction in scab was observed.

The influence of ammonium sulphate and nitrate of soda in the development of scab is shown by the results of a test conducted in 1921. Where all nitrate of soda was used only 20 per cent of the crop was clean, as compared with 42 per cent where sulphate of ammonia was used. In view of these results the potato grower can well afford to give serious consideration to the question of source of nitrogen in his potato fertilizer and avoid the use of large amounts of nitrate of soda where scabby potatoes have been grown in the past. Further information on this subject may be obtained by writing to the New Jersey Agricultural experiment station at New Brunswick.