Influence of Preharvest Sprays with Maleic Hydrazide on the Sprouting of Potatoes

Abstract

1. The application of maleic hydrazide 6 weeks before harvesting the crop at any one of the concentrations used—0.25, 0.50, and 1 percent—had a marked detrimental effect on yields of potatoes. A considerable proportion of the tubers in these plots were small and malformed. 2. There were no significant differences in yields between potato plants treated 4 and 2 weeks before the crop was harvested. 3. Such plots yielded significantly less where sprayed at the 5-percent level than did the control plots. 4. Application of maleic hydrazide, regardless of time of application and concentration, resulted in dieback of plants and the development of a chlorotic condition. 5. The best results from the standpoint of sprout inhibition were obtained when 0.25-percent maleic hydrazide was applied to potato plots 4 weeks prior to harvesttime. 6. Regardless of time of application or concentration of the maleic hydrazide, the sprouting of potato tubers was significantly lower at 45° than 68° F.