-8- 



bases of the present year's shoot growths are affected first, but soon leaves 

 farther up the shoots may show the trouble. Affected leaves often drop off, 

 and branches which appeared normal in June and early July may lose all their 

 loaves by mid-September except for a few close to the tips of the shoots. Some- 

 times, hov/ever, the scorched leaves seem to cling tenaciously, especially on 

 older trees, and more often with some varieties than others, spur leaves are 

 likely to scorch severely without dropping. Yellow banding aoid mottling of 

 leaves are symptoms of the deficiency with some varieties, but not so much with 

 our main varieties, Mcintosh, Baldwin and Dolicious. Magnesii^m deficiency not 

 only seems to increase preharvest fruit drop but "hormone" harvest sprays are 

 much less effective on such trees. 



As reported before, magnesium deficiency is usually associated with 

 acid soils although this is not necessarily the case. Also, heavy use of 

 potash has seemed to increase the trouble. Suggested control measures include 

 the application of adequate amounts of high magnesium limestone worked into 

 the soil if possible, plus the supplemeiitary use of magnesium sulfate (Epsom 

 salts) or some other soluble magnesium compound. Hov/ever, this deficiency has 

 been somewhat difficult to correct in England ajid Canada where it has been 

 recognized for a number of years. It yields less readily and less quickly 

 to treatments than deficiencies of nitrogen, potassium, or boron, for example. 

 For some reason, affected trees are slow to take up added magnesium. It is 

 important, therefore, that growers determine as soon as possible if their 

 trees are affected with this deficiency so that control measures can be started. 



Experiments are under way at Massachusetts Experiment Station and else- 

 where to determine the effectiveness of various treatments. 



— Lawrence Southwick 



HARVEST SPRAYS AND DUSTS 



In 1942, spray and dust applications to control prteharvest drop vrere 

 compared in the Experiment Station orchards at Amherst on Duchess, Vfealthy, and 

 Mcintosh. Applications on mature Mcintosh consisted of about 30 gallons of 

 spray and 3 pounds of dust, and on Wealthy and Duchess similar liberal appli- 

 cations according to tree size. The following selected data give a good pic- 

 ture of the results in general. Spray concentrations are 10 parts per million 

 (p. p.m.) unless otherwise noted. (The numbers indicate commercial brands of 

 sprays and dusts.) 



Variety 



Duchess 



Yfealthy 



