BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 81 
56 percent of nearly 700 wheat collections. This race comprised 40 
percent of the nearly 1,000 isolates. Race 15B was followed in order 
of prevalence by race 50 (26 percent), race 38 (9 percent), and race 
IT (9 percent). 
Race 15B was detected in stem rust collections made from Texas 
and Mississippi northward to Wisconsin, Minnesota, and Xorth Da- 
kota. Twenty-seven races were isolated from rusted grain, including 
a number of unusual ones that came principally from barberry-infested 
areas. Race 11, widely prevalent a few years ago, was found in 9 
States. This race is of particular interest, since it is especially 
virulent on certain varieties that are being used as parent stock in 
a cereal breeding program. From 404 uredial collections of oat stem 
rust. 430 isolates comprising 8 races were obtained. Race 7 was the 
most abundant followed by races 8 and 12, respectively. Races 5, 
6, 10, 12, and 13 were also found. Race 6, a race that at high 
temperatures attacks varieties with the Hajira type of resistance, was 
found only once. This variability of races found in barberry-infested 
territory this year again demonstrates the major importance of the 
barberry as a hybridizer of a large variety of rust races. 
New chemicals tested against barberries 
Test plots in Colorado, Pennsylvania, and Virginia provided infor- 
mation on the effectiveness of new chemicals and new combinations of 
old formulations on both native and common species of barberry. 
Tests in Colorado showed that 2,4-D as a foliage spray is as effective as 
a mixture of 2,4-D and 2,4,5-T on Berberis fendleri. The 2,4-D was 
adopted for field use, resulting in a reduction in eradication costs of 
$11.20 an acre. 
Two chemicals,, MCP (2-methyl, 4-chlorophenoxy acetic acid) and 
a formulation of 2,4-D, 2,4,5-T with a penetrant, appear to be effective 
on B. vulgaris. These are the first formulations of hormone-type 
chemicals that have given a good kill of this species. These formula- 
tions will be tested in the field in 1952. Hormone-type chemicals 
now used in the field on native species of barberry continue to give 
satisfactory results in field programs. The cost of the chemical used 
in a unit area has been reduced about 60 percent as compared to the 
older sodium chloride and chlorates applications. 
Six million barberry plants certified for movement 
Enforcement of the quarantine on the interstate movement of 
barberries, mahonia, and mahoberberis required the inspection of 
nearly 300 nurseries. Permits for shipment of approved stock were 
issued to 68 dealers in 41 States. Varieties of Japanese barberry made 
up the greater part of stock inspected in the field. Six million plants 
of this species were approved, 3% million greenleaf and 2'^ million 
redleaf. Approval was withheld from 5% million B. thunbergi that 
did not meet the 2-year-oid-stock requirements, from 230 plants -l ill 
undetermined as to susceptibility to stem rust, and from 60,000 2- 
year-old plants presumablv of this species that did not conform to 
type. 
Organization changes were made in 1951 to reduce overhead costs 
and to improve administration of this work. Eighl States were com- 
bined into four areas, with consequent reduction in supervisory and 
clerical personnel. Three State offices were closed. 
