XLI 
THE BARBERRY BUSH IS AN OUTLAW 
I SN’T IT ODD that a tiny spore, riding on the wind, so 
small that it can be seen only with a microscope, costs 
the wheat growers of the Northwest $200,000,000 in a 
single season! 
Yet a spore did just this during the Great War. It was 
the spore of the black stem rust, which, when it has its 
way, blights the wheat crops of whole states. 
These spores are tiny plants that live on other plants. 
In the winter they live on straw that lies in the fields. 
When spring comes, they find it necessary to move if 
they are to prosper or even to live. Strange to say, there 
is but a single plant in all the world on which these spores 
can make springtime homes. Those plants are barberry 
bushes. Unless they find barberry bushes, they die. 
If they find these bushes, they thrive and multiply and, 
when summer comes and conditions are just right, they 
ride away again on the winds of the wheatfields, which 
are their happy hunting grounds. There they multiply 
so fast that they are very likely to blight crops of whole 
communities. 
This particular species of barberry is an ornamental 
plant used in yards and for hedges. It is familiar prac¬ 
tically all over Europe and America. It was not in 
America, however, before Europeans came. They intro¬ 
duced it. Not knowing the menace that lay back of it, 
settlers carried it west with them as they established their 
82 
