BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 71 
sonnel and cooperators in the important grain-growing areas. Kust 
losses were determined and 1,400 infected specimens of grain and bar- 
berry were collected for physiologic-race determinations. A total of 
303 nurseries with an inventory of 16 million barberry and mahonia 
plants were inspected and certificates were issued. Permits were 
granted to 83 dealers to ship approved barberry stock interstate. 
Changes in procedures during the year have lowered operating costs 
for barberry eradication and have inceased accomplishments. Final 
reworking of areas is now done only on evidence of need, established 
through reconnaissance surveys, rather than on a fixed time schedule. 
Old barberry sites are now worked by one or two men rather than the 
former crews of five to eight men. State and local agencies and farm 
operators are being urged to assume more responsibility for the 
cleanup work. 
Improved methods of application and new hormone-type chemicals 
have materially reduced the cost of eradicating barberry bushes. For 
example, sprays of 2,4-D were used to kill native barberry in Colo- 
rado. A combination of 2,4-D and 2,4,5-T plus a penetrant was used 
for similar work in Virginia and West Virginia. Less than 0.5 per- 
cent of regrowth was apparent 2 to 3 years after treatment. Field 
tests have shown that 2-methyl 4-chlorophenoxyacetic acid is effective 
in killing Berberis vulgaris. This chemical is now being used on a 
field basis in Pennsylvania and may speed eradication in heavily 
infested barberry areas. 
There are still 33,000 square miles requiring initial barberry eradi- 
cation work. More than 50,000 square miles need reworking one or 
more times in the future. Areas are placed on maintenance when the 
necessary initial work and rework have been completed to a point 
where barberry has been eliminated or brought under practical con- 
trol. With more than 900,000 square miles in a maintenance status, 
increased attention is being given by Federal and State agencies to a 
program designed to keep this territory free of barberries. This pro- 
gram involves locating bushes that were missed in previous surveys 
or that inadvertently have been shipped in from States outside the 
eradication area. 
Losses from stem rust in 1952 were confined principally to parts 
of Minnesota, North Dakota, South Dakota, and to barberry-infested 
areas in New York, Pennsylvania, Virginia, and West Virginia. 
Race 15B of wheat stem rust, which was found on or near barberry 
prior to 1950, and which became widespread in 1950, extended its range 
throughout most of North America in 1952. This race made up about 
60 percent of all races obtained from 1952 collections of rusted grains 
and grasses. 
It has been determined that race 15B can attack all winter and 
spring wheats now in commercial production as well as most of the 
resistant parent stock used in the small-grain-breeding program. 
Some varieties of wheat now being used as a source of resistance to 
race 15B in the breeding program are highly susceptible to some races 
of the stem-rust fungus that were prevalent more than a decade ago. 
These races have persisted on barberry from year to year since that 
time. Of these races, 11, 49, and 139 can attack certain varieties even 
more severely and under a wider range of conditions than can race 
15B. 
