52' Director's Report of the 



In the farmers' business experiments (6 to 15 each year) the 

 nine-jear averages are as follows: 



Increase in yield, 36.1 bushels per acre. 



Total expense of spraying, $4.74 per acre. 



Net profit from spraying, $14.43 per acre. 



In 1911, the Station made a comparative test of lime-sulphur, 

 lead benzoate and bordeaux mixture for spraying potatoes. The 

 results of the experiment plainly show that neither lime-sulphur 

 nor lead benzoate can be profitably substituted for bordeaux in 

 spraying potatoes. Both lack the stimulative influence possessed 

 by bordeaux while lime-sulphur also dwarfs the plants and lowers 

 the yield. A repetition of the experiment in 1912 gave similar 

 results. For details of these experiments see Bulletins 347 and 

 352. 



Crown-rot of fruit trees. — Crown-rot is a disease of trees in 

 which patches of dead bark or bare wood occur on the trunk near 

 the surface of the soil. An extended investigation of this disease 

 shows that it is due chiefly to winter injury. It is most liable 

 to occur on trees in wind-exposed situations, particularly on those 

 which have made very rapid growth and gone into the winter 

 with their wood unripened. Hence, it appears probable that it 

 may be at least partially prevented by planting the varieties 

 which are least susceptible, providing windbreaks, heading low, 

 avoiding excessively rapid growth and inducing early ripening of 

 the wood, In order to prevent trunk rot which often follows the 

 initial injury the areas of dead bark should be detected and 

 treated as early as possible. The trunks of young apple trees 

 should be carefully examined twice a year — May and July. 

 Wherever dead bark is found it should be carefully cut away, the 

 wound disinfected with a 1 to 1,000 solution of corrosive subli- 

 mate and then covered with grafting wax or gas tar to keep out 

 moisture and induce healing. A full account of the investigation 

 is given in Technical Bulletin 23. 



plant nutrition. 



The only work in plant nutrition, the results of which have been 

 published during the past five years, is a report of experiments 



