44 ANNUAL REPORTS 01 DBPABTMBNT OF AGRICULTITIK, 1935 
RUST SURVEYS 
Except in certain Localities in Minnesota and North Dakota, the 1934 
from stem rust in the spring-wheal area were very Blight During the spring 
barberries became Infected earlier than usual and a considerable numb 
local epid mics ol rust developed neaz them, bul high temperatures, together 
with the drought, prevented a damaging spread of the fungus, except In those 
localities where there were frequent dews or show* urediniaJ stage of 
stem rust of wheat did not survive the winter of II commonly in Texas 
as in some other years. There was, however, considerable overwinter! 
Seven hundred and eighty-two rust specimens collected in 1934 were identified 
ns to the physiologic forms present. The most surprising result of this work 
Was the fact that form 56, heretofore unimportant and not wide-spread, < 
nned 30 percent of the total number of collections identified, whereas form 34, 
which also had been relatively care, constituted 20 percent of the total. A 
btained from each 'three collections from barberry bushes, while a 
different form was found in each 35 collections of rust obtained from grain plants 
away from barberries, further indicating that the hushes are an important fac- 
tor in the persistence of physiologic forms and the production of n< w i 
During the whiter of 1934 -35 the uredinial stage of stem rust of wheat over- 
wintered rather abundantly in Texas hut little was found on oata Becaus 
large acreage of hit.' wheat in Kansas and Nebraska, rust developed fai more 
abundantly in those States in the spring of 1935 than is usually the case. Fre- 
quent rains and favorable temperature contributed to the rapid spread of the 
fungus, 'i ally cool, wet weather during May and the first half <»f June 
resulted in heavy stands and a succulent growth of grains in the spring-wheat 
area. The crops wore from a week to 10 days, and in some - 2 weeks 
late, with other conditions ideal for the development of rust. Strong ^outh 
wind- en June '2:', and 2-1 carried an enormous Dumber of spores from Kansas and 
Nebraska into th • spring-wheat area. On June '2'.) spores caught on vaselined 
slides at St Paul indicated that they were falling at the rate of P< square 
foot each in 24 hours. A^ a result of weather conditions favorable for the spread 
of the rust, combined with other circumstances described, the most wide-spread 
epidemii <•;' v. i rust in recent years occurred in the summer • 
Although some local rust epidemics developed on rye and other grains near 
barberry bushes tl relatively little rust on oats ami rye away 
bushes, further indicating that wind-blown inoculum was the important factor 
g io the extensive to wheat this year. Had barberry bushes 
been numerous in tl Dal ml Minnesota it is evident that oats, rye, and 
barley \ ul : not bav \ escape I serious damage. 
CLASSIFICATION OF BARBERRI 
Approximately l I" different species, varieties, and hybrids of barberries have 
been obtained from the Arnold Arboretum and nura oughout the United 
planted in an experimental plot at Bell, MT l>u .11 of L934 
and again in the spring of 1935 tests were continued to determine the rust sus- 
ceptibility of the individual species. The outdoor test coi nned data obtained 
r controlled conditions. In determining tl a of barl 
renl varieties of stem rust in the gre nh< St Paul, a number of 
rust < ere made and considerable evidence was obtained that in nature 
may result from such crossing, 
ag the past year 27 nurseries request! ig permits to ship species of bar- 
■ than Japanese were Inspected, in keeping with the provisions con- 
tained In Quarantine No. Certificates to the nurseries that 
qualified were Issued by the Division of Domestic Plant Quarantines. 
TRICK CROP AND GARDEN INSECT INVESTIGATIONS 
WIREWORMS 
Investigations on the control of wireworms in the Irrigated areas of the \ 
have been continued, the mi ••: ted Including s »il fumigation with naphtha* 
lene, tl oding at ;i period when the air temperatures are high, drying out of the 
soil, trapping of adults, and crop rotation. The work on the Bandy land wire- 
In South Carolina has been completed, ami these Investigations show 
