SOME BACTERIAL DISEASES OF PLANTS 
By WALTER G. SACKETT 
FOREWORD 
It is the purpose of this bulletin to call attention to some of the 
more common bacterial diseases of plants which are either present in 
the State or may be expected in the future, with the hope that the 
old adage, “To be forewarned is to be forearmed,” may be of some 
avail. With one exception, the diseases here treated are well 
known in the Eastern and Central States, where they have caused 
immense losses to gardeners and fruit growers. Where remedies 
are known, they have been suggested, but it is the deep regret of 
the plant pathologist that for the majority of bacterial diseases 
no efficient treatments have been discovered and prevention is the 
only hope. 
While the climatic conditions of Colorado may be said to be 
on the whole unfavorable to the development of diseases in plants, 
especially fungus troubles, the fact remains that there are some 
localities which have suffered heavily from causes traceable to 
bacteria. Nature has blessed this State with conditions which af¬ 
ford all that could be desired toward the natural prevention of bac¬ 
terial diseases; the dry air, the limited amount of rainfall and the 
abundance of sunshine, all combine against the growth of germs. 
The soil of Colorado is comparatively new so far as agricul¬ 
tural practices are concerned, and with the change in its character 
and fertility, brought about by continued cropping, we shall ex¬ 
pect to find many of our cultivated plants becoming more and more 
susceptible to the attacks of microorganisms. 
With the introduction of new plants, new varieties of old 
plants, foreign seeds, and strange nursery stock, it is not at all im¬ 
probable that previously unheard of diseases will make their ap¬ 
pearance. 
Again, as the farming communities become more thickly popu¬ 
lated and more new land is cleared and brought under cultivation, 
the danger of plant diseases spreading from farm to farm is greatly 
increased. 
Plants and trees, like human beings and the lower animals, are 
affected with contagious diseases which spread from individual to 
individual, from field to field, and from ranch to ranch in precisely 
the same manner as any contagion is communicated from one 
member of a family to another. The more densely a city is popu¬ 
lated, the greater is the danger from the spread of disease and the 
more stringent must be the laws which govern the sanitation of 
