38 ANM AL i:i:!'<Hi rs or r.Mi:NT of AdiucuLTriiK. 1937 
ENFORCEMENT OF THE WHITE PINE BLISTER RUST QUARANTINE 
'Ihi- regulations of the white piiie blister rust quarantine require a Federal 
I)iiie-sliii)T)inK permit in the interstate movenienl of live-leaved pines from the 
Infected iStates to any State other than New York or the New England States. 
Such iierniits are issued only for live leaved pines which have heen j,'rown under 
FpcH-ilii'd sanitation conditions. Applications fur shii»ping such pines in the fiscal 
rear llJoS have heen received from 57 nurseries. The work of eradicating cur- 
rant and goosel>erry plants, the alternate hosts of the disea.se, from the wiuita- 
tion zones surnamding the.^e inirseries and of insiK'Cting the zones to insure 
compliance with the quarantine regulations was completed in the spring of 
1937 prior to the time when the rust normally appears on such plants. The 
environs of nurseries of TiO applicants were found to he in a satisfactory con- 
dition, including 14 Federal and \) State nurseries growing live-leaved pines for 
soil conservation or reforestation purposes. 
The States of ^^'isconsin. Ohio. Pennsylvania, and Maryland re<^ently estab- 
lished white pine l)lister rust control ari as for the purpose of proiccling valuah'e 
stands of live-leaved pines. In such areas the planting and possession of currant 
and gooseberry plants is prohibited under State authority. Tlie Federal (juaran- 
tine was accordingly revised, effective March 1, 1037, to provide that no currant 
or gooseberry plants may be shipped to these States without a control-area i)er- 
mit, ol)tained from the resi)onsible officer of such State. FourteiMi States now 
have legally established blister rust control areas. 
During the year 110 violations of the quarantine regulations were intercepted 
by transit inspectors, and t)4 were intercepted by roadside inspectors of other 
projects. 
CEREAL AND FORAGE INSECT INVESTIGATIONS 
INSECTS ATTACKING CORN 
Surveys of European corn borer x)opulations in 1930 show that in western 
Ohio and in the southeastern counties of Michigan, where moisture conditions 
approached tlie normal, there were significant increases in the rate of infesta- 
tion over those observed in 193-'). In the drier areas, such as eastern Indiana, 
.soutli western Ohio, parts of Michigan, and the Eastern Sh(»re of Maryland, 
definite decreases in infestation were indicated. Significant increases in the 
rates of infestation were recorded in parts of Vermont. Massachu.^etts, Connec- 
ticut, Rhode Island, and New Jersey. In spite of the decrease in infestation in 
some areas as a result of drought conditions, the loss resulting from borer attack 
was higher in 1936 than in any previous year, owing in part to the increa.sed 
value of the corn crop. A second generation of borers appeared in significant 
numl)ers in the Great Lakes area previously considered as a one-generation area. 
Experiments with the.se borers during the year indicate that the two-generation 
individuals may be physi<tlogically different from the one-generation strain but 
not i)hysiologically identical with tlie mtdtiple-generation strain. Wh.etlier the 
two-generation liabit occurring in these areas in 193G will persist is unknown. 
Adult corn borer parasites to the number of 3r».4S;s were released in 3.') colonies 
in 10 Stales. This material was obtained from European and oriental importa- 
tions, from domestic collections in Massachusetts, and from material originating 
from Canada which was reared in the laboratory, and included the following 
species: huirrolntn puucforia Roman, Mirrof/mitcr tibialis Nees. Crcwnstus fla- 
roorhitahi Cam., Liidclhi (/ri.'<rsrcn.s R. D.. and Chclovun (unniliprs We.^m. /. 
puvrtoria and L. f/ri.scscoKs appear to be particularly efFe<*tive. and C. nniniliprg 
shows mu<h promise in the Lakes area. A method has been develop(-<l for 
rearing this last-mentioned species on the Medit(^rranean flour moth to supply 
adults for colonization. Inv»'stigations of inbred lin(»s of field :)nd sweit corn 
sliow several of bolli types carrying marked n>sistance. The most i!np<irtant 
development in this work in 193(J is the drnionstraiiou that a considerable degn^ 
of re>-istance is inherent in oi-e of the most favorable crosses, and this is not 
explained by tlu» tightly wrai)i)e(l tassel of this strain— a character to which 
most of the r(^sistanc(> in this line had previtmsly been ascribed. Not r.nly is 
there a large reduction in the number of liorers surviving in this strain when 
infested ])revi(»us to tasseling. but those borers that survive are stuntt^l and 
hick vitality to meet winter conditions. In an extensive test of Inbred lines of 
NW(M't corn certain lines exhibited resistanci^ that is not associated with date of 
planting or the eclosion «>f the tassel, thus giving ('ucourairement for further 
work of this character. Detailed studhv><. however, have indicated that <late of 
