424 BOARD OF AGRICULTUEE. 



"Too great care can not be taken to avoid cutting or otherwise injuring 

 the roots of the trees bj^ plowing or other cultivation. Though the mycel- 

 ium of this fungus is able to enter the cortex of perfectly healthy roots, 

 yet its progress, as well as its entrance, is greatly facilitated by wounds 

 of any charactei-. In one of the orchards visited 1)y me last fall it was 

 apparent that in some cases the nij'celium of this fungus had first entered 

 the roots through wounds made by the plow in cultivating between the 

 rows. 



"Attention has frequently been called to a practice among some fruit 

 growers of placing in the bottom of a hole, in which they are about to set 

 a tree, a quantity of chips from their wood pile. In many of these chips 

 there are sure to be found some of the mycelium of this fungus and the in- 

 troduction of the disease into the orchard is the result of this practice in 

 many cases. For it is a well-known fact that each small piece of mycelium 

 of this fungus is capable of remaining dormant for long periods and of 

 again producing, when placed under proper conditions, the mycelium 

 and even the normal sporophores of the species. 



"It was early found in these investigations that the disease was largely 

 or entirely confined to those orchards that were planted on recently cleared 

 timber land. In fact, the disease has never been reported in this State 

 from ox-chards planted out on real prairie soil. Subsequent investiga- 

 tions have afforded abundant proof that the fungus described in this 

 bulletin is common as a parasite and also as a saprophyte on various spe- 

 cies of oak in this State. 



"Old oak stumps or even dead oak roots remaining in the soil are 

 apt to become fertile sources of the infection of the healthy trees planted 

 in that same soil. From the above it follows that it is the part of wisdom 

 to remove all old oak stumps from the orchard and to dig up all roots 

 of such trees remaining in the soil. These should be carefully burned 

 and in no case allowed to remain on the surface of the soil. 



"From the nature of the disease the application of any fungicide as 

 a remedial agent can not be recommended at all. And there is much 

 doubt if their application to the soil will effectually prevent the spread 

 of the mycelium through the soil from diseased trees or stumps. This is 

 made probable from the fact that these fungicides are apt to lose their 

 effectiveness in the soil through chemical combinations with other things 

 present in the soil. 



"It is very doubtful if any great good will result from 'liming' of the 

 soil or from mixing a large amount of wood ashes with the soil. Neither 

 of these methods would be of the slightest value as remedial methods, and 

 further tests must b6 made before any value is ascribed to them as pre- 

 ventives of the further spreading of the mycelium. 



"And though thorough cultivation of the soil is always to be recom- 

 mended for other reasons, yet this may not tend to greatly reduce the 

 spread of this disease. The thorough cultivation of cleared timber land 



