166 Principles of Plant Culture. 
The fungi multiply from extremely minute spores (53) 
that are produced in immense numbers, and when mature, 
are very readily blown about by the wind. Many of them 
also multiply from thread-like organs called mycelia (my- 
ce’-lia), something in the same manner as Canada thistles 
multiply from their roots. 
322, Methods of Controlling Fungi are of three 
classes: 
a— Removing and destroying the affected parts; 
b — Preventing the germination of the spores; 
c — Destroying the fungus itself by applying some de- 
structive material, (a fungicide (fun’-gi-cide)). 
323. Destruction of the Affected Parts is the most 
effectual preventive. known in cases where the fungous dis- 
ease attacks a portion of the plant whence it spreads to the 
remaining parts, as in the black knot of the plum,* the 
blight of the pear, apple and quince,t and the red rust of 
the raspberry and blackberry.{ 
The affected part should be removed as soon as discovered, 
and burned at once, to destroy any spores of the fungus it 
may contain or which might mature later. It is generally 
important to cut the diseased branch some distance below 
the point of visible infection, as in many cases the mycelia 
of the fungus extend farther than external appearances 
indicate. 
324, Preventing Spore Germination is the only 
known method by which we can combat the fungi develop- 
ing within the host plant (endophytic (en-do-phy’-tic) fung7). 
In fungi that develop from spores planted with the seed, 
as the smuts of the small grains, spore germination may be 
* Plowrightia morbosa. + Microccocus amylovorus. t Ceoma luminatum. 
