STATE POMOLOGICAL SOCIETY. 55 



mycelium of the fungus is usually beneath the surface of the plant 

 affected makes "remedies" ineffective. There are a few instances 

 — as some of the surface mildews — which are exceptions and v.here 

 remedies are effective ; but such are rare. 



In the treatment of fungous diseases, two distinct lines should 

 be followed : 1st, hygienic ; 2nd, preventive. There are definite 

 laws of health for plants as well as for animals, and in either case 

 neglect of those laws invites disease. 



Common sense would demand first of all that the trees or other 

 plants be in good vigorous condition. Healthy vigorous plants are 

 always less susceptible to attack either of insects or of fungi than 

 are those which are weakly or stunted. 



Next remove all possible sources of infection, such as wild plants 

 subject to the same disease, leaves and decaying fruit which are 

 affected and which form a very common and the most important 

 source of trouble. The wild plum and cherry trees are an ever 

 present menace to plum growing in Maine because they form a well 

 nigh indestructible source of infection from black knot. The wild 

 blackberries in any locality often harbor the orange rust to such an 

 extent as to render impossible the cultivation of the choicer 

 varieties. Diseased fruit and leaves effectually harbor parasitic 

 fungi during the winter, and on the approach of warm weather the 

 spores develop rapidly and are at once liable to be carried to the 

 opening buds by the first breeze that stirs. No preventive meas- 

 ures should be expected to be effectual if such sources of infec- 

 tion are left undisturbed. It is not enough to feed diseased fruit 

 to the hogs or tcf place it on the compost heap, but it should be 

 carefully gathered and burned. 



The mycelium of some fungi lives from one year to another in 

 the branches or canes of affected host plants. This is noticably 

 true of black-knot, of the twig-blights and of raspberry anthracnose. 

 In such cases the first treatment demanded is the removal and burn- 

 ing of all affected canes or branches. I would again emphasize 

 the importance of burning. A diseased branch left on the ground 

 is just as much a menace to remaining plants as if it had not been 

 cut. In some instances, as in case of the dreaded "black-knot," 

 it is often thought advisable after removing a diseased branch to 

 make an application of some material to the wound in the hope of 

 destroying any possible remaining portion of the mycelium. 



Dark moist weather, and damp shady locations are always con- 

 ducive to the development of fungous diseases. Hence open train- 



