164 [ DISEASES OF THE MULBERRY 



a sickly condition in the summer and autumn, with 

 yellowish weak growth, and dies soon after the foliage 

 is shed, early in winter. The disease is due in the 

 first instance to the inability of the roots to resist to 

 the unfavourable conditions of the soil, whereupon the 

 rootlets die off gradually, and the main roots thus 

 weakened become an easy prey to the various fungi, 

 chiefly to Armillaria mellea, the mycelium of which 

 completes the work of destruction in autumn and winter 

 when the vitality of the tree is at its lowest ebb. If 

 the rootstock of the dead tree is allowed to remain 

 in the ground, there is a great probability that sooner or 

 later, perhaps in the following autumn, the characteristic 

 large clumps of Armillaria in full fructification will 

 sprout all around it. The disease may make its 

 appearance also on well-drained red soils of good quality, 

 but in this case the malady has been provoked by 

 repeated and grievous wounds inflicted to the main 

 roots during careless tillage. The mycelium of Armillaria 

 at first establishes itself saprophytically on the injured 

 wood of the roots, but soon spreads to the healthy 

 tissues becoming a true parasite and killing the tree. 

 Moreover, it happens now and then to see several 

 mulberry trees situated within a radius of 20 metres 

 around a tree which had succumbed to the disease, 

 become sickly in their turn and die off in the same 

 manner, in the following winter or within a period of 

 three years from the death of the first tree, particularly 

 if the stump of this tree has been allowed to remain 

 long in its place before removal. In this case it is 

 obvious that the mycelium has spread from the dead 

 roots of the tree to the healthy roots of its neighbours. 

 It is also noteworthy that another mulberry or a black 

 mulberry or a fig tree planted in the same place where 

 one of these trees had died from this disease some 

 time before, very generally succumbs to the same 

 malady in a short time after it had become established, 

 the poison lingering in the soil for a considerable 



