198 The Plant World. 



the same species and the sa:r,e number of colonies in general. 

 When the ground was covered with snow spores appeared in 

 the trap cultures. 



A very notable fact, however, in regard to the influence of 

 ground cover upon the number of spores in the air of the orchard, 

 comes from two sets of exposures which were made at Hartley's 

 orchard, the one on March 17th and the other April 6th. 



Stations 1, 2, 3, and 4 were made in the old orchard, and 

 5, 6, 7, and 8 in the new orchard. 



In the old orchard the weeds had been permitted to grow 

 unmolested and the trees were badly in need of pruning. In 

 the new orchard, the ground cover was a closely mowed sod, 

 and the trees were in good condition. These two orchards m.ight 

 be taken as typical of the "cared for" and "neglected" orchards 

 as found everywhere. By a comparison of the" cultures from, the 

 orchards it can be seen that the number of fungi in the latter 

 is very much greater than in the former. This represents a very 

 interesting fact. Its significance to orchardists can not be 

 over-emphasized. Where weeds, trash and rubbish are allowed 

 to accumulate, a better harbor for fungi m.ay be expected than 

 where conditions are the reverse of these. 



While it may be maintained that it represents conditions 

 as they exist, only during the trees' inactivity, yet this is too 

 significant to be lightly passed over. It would be only natural to 

 expect that the greater the number of fungi when the tree begins 

 its activity, the greater would be the chance of sufi"ering fro:n 

 their attacks, or perhaps succumbing to them. We use sani- 

 tary measures to protect the health of the home. It is no less 

 necessary if we would maintain healthy trees, that we establish 

 sanitary conditions as regards orchards. Nothing could more 

 forcibly point to the value of such care than the following 

 tabulation : 



