STATE HORTICULTUEAL SOCIETY. 169 



tlireads, which become more and more abundant and compact till 

 the roots finally all die and rot. In the last stages a tree can be 

 puslied over or pulled n]i by the hand, even while the top still shows 

 signs of life. 



Examination of these white fungus threads shows them to be 

 the mycelium or vegetative under-grown part of some of the fleshy 

 fungi usually known as ''toad-stools." These plants, so commonly 

 occurring on dead wood and other decaying vegetable substances, 

 very rarely attack living plants. A few of them are, however, 

 known to be parasites, and it seems that another, and that one of 

 the most common, must be added to the list, ior Pali/ jiorns rersicolor 

 is frequently found developing on trunks of trees that have died of 

 root rot in such a manner as to leave little doubt of its connection 

 with the white threads on the roots. 



Trees planted in new ground that is full of decaying roots, 

 chips, etc., the usual nidus of this fungus, are more apt to be 

 attacked than those in older land that is free from decaying wood. 

 This shows the probable source of contagion. The disease also 

 -spreads slowly from tree to tree, probably from the contact of the 

 roots, so that in the course of years considerable areas are completely 

 denuded of trees. It is useless to try and fill such vacancies, for the 

 new trees are usually destroyed by the disease before they become 

 well established. Although so destructive in its results, this disease 

 develops (juite slowly, several years often elapsing from the time a 

 tree is attacked till it finally succumbs. In fact, on moist, rich soils, 

 and Avith liberal culture, the tree is often able to outgrow the fungus, 

 making new roots faster than the old ones are destroyed. Under 

 such circumstances the disease does but little damage. It is in 

 grassy and neglected orchards, and especially on poor, dry hillsides, 

 that it is most to be feared. Removing the e.irth from the crown 

 and large roots of the tree when its diseased condition is first noticed 

 and applying a liberal dressing of lime, often proves an effective 

 remedy. The best safeguard is, however, to give the orchard such 

 treatment as will induce a continued luxuriant growth; but un- 

 fortunately this is the very condition which renders it most liable to 

 •serious injury from blight. In fact these two diseases are the 

 " Scylla and Charyljdis" of pear-growing, for in seeking to avoid the 

 one we are liable to subject the orchard to serious loss from the 

 other. Apple and cherry trees suffer equally with the pear from this 

 disease, and the same or a similar fungus attacks the roots of many 

 other trees and shrubs. 



LEAF-BLIGHT. 



{Morthiera Mespile^ Fckl.^ 



Following German authorities, Prof. Arthur calls this disease 

 '• leaf-brownness," and uses the term "leaf-blight" for the scab 



