10 UNIV. OF N. H. AGR, EXPERIMENT STATION [Bulletin 232 



CAN WINTER HARDINESS BE MEASURED BY DYES? 



Studies on absorption of certain aniline dyes by pulverized apple twig 

 tissues by Dunn and Bakke in 1924-25 at Iowa State College indicated 

 that this test might have some value as a means of determining relative 

 hardiness; and during the past year studies were made here by Mr. 

 Dunn on samples of twigs obtained at the close of the growing season. 

 Twenty-two well-known commercial varieties of apples were used pos- 

 sessing a gradation in resistance to unfavorable weather conditions from 

 extremely hardy down to the rather tender. Among the more hardy 

 were such varieties as Hibernal, Patten Greening, Mcintosh, Oldenberg 

 or Duchess, Wealthy, Virginia Crab and Red Astrachan. At the other 

 extreme among the markedly tender varieties were Ben Davis, Stayman, 

 Winesap, Baldwin, Delicious, Maiden Blush and Roman Stem. Some- 

 where between these extremes will be a group exhibiting moderate 

 hardiness, such as Malinda, Fameuse, Peerless, Salome, Grimes Golden, 

 Northwestern Greening, and Yellow Transparent. In these samples a 

 better correlation than the year before was found between the results 

 of the adsorption tests and groupings according to hardiness. About 

 five or six varieties were out of agreement. The readings varied from 

 .018 in the case of a hardy variety to .105 in the case of a tender one, the 

 figures representing the fraction of dye left in solution after adsorption. 

 (Adams Fund.) 



WHEN DO FUNGICIDES DAMAGE PLANTS? 



One of the handicaps in the use of Bordeaux mixture has been the 

 injury caused by various combinations of this fungicide on the plants. 

 Studies conducted by O. Butler during recent years have shown that 

 the injuries are caused where the proportion of lime in the mixture is 

 low. When four times as much lime as copper was used, no injur}' 

 resulted on the apple, although it was necessary to make the proportion 

 six to one in the case of peach. 



During the past year these studies dealt particularly with the relation 

 of meteoric water, dew and rain. It was found that the peach and apple 

 suffer no injury from spraying provided the foliage is protected from 

 dew and rain. When such precaution is not taken, however, injuries 

 decrease as the per cent of lime in the mixture increases. (Adams 

 Fund.) 



CONTROL OF BITTER-PIT 



Indications that the disease of bitter-pit of apples is more serious in 

 the "off years" of Baldwin trees are suggested in studies that have been 

 conducted by O. Butler. In 1924, when there was a heavy apple crop, 

 an average of only 2.38 per cent of bitter-pit was found. The next 

 season, which was an off year with a light crop, the percentage of bitter- 

 pit jumped to 18.87, while in 1926. a productive year again, it was only 

 1.40. The mean weight of fruit produced per tree in 1924 was 443.38 

 pounds; in 1925, 25.32 pounds; and in 192G, 352.45 pounds. (State 

 Fund.) 



