56 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE, 1936 
from Texas and other southern States. A combination of late crops In the 
winter-wheat area and delayed development of spring wheat in the Dakotas 
and Minnesota resulted in conditions Ideal for the development of the epi< i 
whereas In the norma) year Inoculum from the South reaches the spring-wheat 
area too late to cause serious damage. 
During the year greenhouse studies were made of more than '."hi collections <>f 
rust from barberries and wheat. Eighty-six percent ot* the barberry collections 
proved to be of the wheat variety of rust, and 'J<; different physiologic forms of 
stem rust were represented, as many as s distinct forms being obtained from a 
single collect ion. A new form was found in every T collections from barberry, 
while a different form was Isolated from each l'i collections from grain. This 
confirms previous observations that the barberry is responsible for the persistence 
of many forms of the fungus that appear not to thrive in the Southern Stat 
RUST-SUSCEPTIBILITY TESTS 
Forty specimens of barberries were tested under greenhouse conditions for 
reaction to Stem rust, with the result that several species heretofore considered 
doubtful were placed in the proper class with respect to rust reaction. Further 
studies of the ecology of the barberry were made for the purpose <»f hotter 
understanding the natural increase in the field. The effect of temperature and 
various stimulants on the germination of the seed was studied. Under natural 
conditions it was found that most of the barberry seed germinated the first year 
hut some remained dormant and continued to germinate for at least 4 years. 
It was definitely established that common salt, generally used for eradicating 
bushes, does not kill seed Lying on the ground. 
Forty new species and hybrids of BerberiS have been added to the approxi- 
mately 160 spedes now growing in the experimental plots in the foreign-plant 
introduction garden at Bell, Md. During April of this year the entire collection 
was again tested for rust susceptibility. Weather conditions were such, how- 
ever, that the test was not as successful as those conducted in 1934 and l'.ioo. 
BARBERRY CLASSIFICATION AND NURSERY INSPECTION WORK 
A- a result of applications received by the Division of Domestic Plant Quaran- 
tines. 23 nurseries were inspected and authorized to ship immune species of 
barberries into protected States. Approximately 4, 200 susceptible barberries 
were eradicated as a result of this Inspection and educational work. During the 
year 140 specimens of barberry were sent in by State leaders in barberry eradi- 
cation, State nursery inspectors, and nurserymen for identification as to species 
and reaction to the rust fungus. The classification work is carried on in 
cooperation with the Arnold Arboretum, .Jamaica Plain, Mass. 
EDUCATIONAL ACTIVITIES 
In recent years there has been a constant demand for specimens and literature 
relating to the barberry-eradication program suitable for classroom US€ in con- 
nection with the teaching of nature study, biology, and agriculture. Renewed 
Interest in stem rust control, brought about as a result of the expansion of 
tioid work witii emergency funds, and the severe damage resulting from rust 
in many Slates during r.». - ;.~>. has resulted in a noticeable Increase in the number 
of Inquiries concerning control measures reaching both state and Federal offices. 
The demand has been met by making available to property owners circulars 
explaining the nature and purpose of the program, placing demonstrations at 
county and community fairs, and by supplying public school teachers with speci- 
mt'iis of rusted L r r;iin and barberry Leaves, as well as literature suitable for 
ela-.-ro.uu and laboratory study. 
An attempt has been made to do some educational work in advance of eradi- 
cation crews, ami. through the various educational means employed, t" obtain 
leads to localities Infested with barberry bushes. The primary purpose of the 
educational work has been t<> stimulate sufficient local Interest in the program 
to result in voluntary action on the part of property owner- in preventing rein- 
festations in communities where control has been largely accomplished and to 
locate undiscovered areas in which barberries have escaped from cultivation. 
Although during the year trained personnel have given practically their entire 
attention to the direction and supervision of laborers employed with emergency 
