Fungus and Bacterial Diseases 55 
If the timely examination of insect conditions has been 
neglected, then the diagnosis will be made when the dam- 
age has begun or has progressed to some degree. The 
insect can be observed at work, the culprit captured and its 
name or character determined. With the leaf-eaters this 
is usually readily accomplished, but the sucking insects 
whose damage is not at once apparent, as well as the bark- 
beetles and borers are discovered by close observation 
only. 
The small round entrance holes in the bark of conifers, 
accompanied by resinous exudation, and finally the loosen- 
ing of patches of bark where the cambium has been de- 
stroyed give evidence of the presence of bark-beetles. The 
presence of borers is indicated by the entrance holes, usu- 
ally near the base of the tree, and by the excreta or finely 
divided wood particles, wood-flour, found at the base of the 
tree. 
Fungus and Bacterial Diseases. The fungus diseases 
of the foliage make themselves known by the partial dis- 
coloration of the leaves, usually in spots of various colors, 
and by the powdery aggregations of fruit-bodies, silky, 
smutty, or otherwise. Sometimes also the foliage wilts 
or dries up. 
As there is only one practicable remedy for all these 
fungi, namely, spraying with poisons, it is not necessary to 
be familiar with the different kinds, beyond recognizing 
their existence. The same can be said of the rot fungi, 
which practically behave alike, and are treated alike. Dis- 
coloration of the wood in wounds, and whitish or yellowish 
mycelia strands breaking through the tissues, and finally 
the fruit-body proclaim the presence of rot fungi. The 
dying of portions of the crown on account of reduced water 
conduction may also be due to these fungi. 
