Evening star., 1939-01-21
Of Stars, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henry.

SNsbS
By Thomas r. Henry.
Plant pathologists are hunting in the
air thousands of feet above the surface
of the earth for the migration routes of
an organism which causes losses of mil
lions of dollars to American farmers
every year.
This is the spore, or seed" of wheat
rust. It strikes somewhere nearly every
year, and strikes hard. For the most
part efforts to breed .rust-resistant
wheat have been only indifferently sue
cessful. Some apparently immune
strains have been produced, only to be-
come susceptible within a few years.
The trouble seems to be that the
organism exists in countless numbers
capable of all sorts of mutations and
evolutionary changes to meet changed
conditions. When a new variety of
wheat is produced which 1t cannot attack
it can very rapidly produce new species
of rust especially adapted for the new
food.
LII n. Otdll SllSoGCA, liSoSA Va liAC NC
partment of botany and plant pathology
of the Oklahoma A. and M. College, is
taking the lead in the present expert
ment. Accompanied by Al Guthrie,
Oklahoma aviator, he plans to undertake
long airplane flights in an effort to trace
the paths of the fungus in the upper
atmosphere, the particular wind currents
xr,l,i ,iol. 1 Ic
months of the year, and the speed with
which it moves from place to place.
The happy hunting ground of this
wheat destroying organism naturally is
the great wheat belt extending from the
Mexican border into Saskatchewan and
Alberta. 1t is impossible to predict where
the rust will strike in any particular year,
or what variety of wheat will most attract
it. These might be predicted, however,
If plant pathologsts were more familiar
with the habits of the tiny spores which
always have free transportation on the
swift wind currents blowing up and down
North Americas great central plain.
Wheat rust spores survive the winter
in Mexico and Texas each year. Then,
according to DR.. Chester's theory, they
are carried northWard by winds as far
as Saskatchewan and British Columbia
In Canada. This northward passage
takes pla"e in series of movements.
But the plant pathologists are mysti-
fled as to what happens to the spores
after the Canadian fields have been at
tackled. The rust apparently disappears
or lies dormant for a while. Possibly
winds from the north may bring them
back, depositing them in the south until
a new wheat crop springs up. Then the
cycle starts all over again with a north
ward movement.
In an effort to prove this point Dr.
Chester plans to adopt methods similar
to those used by Col. Charles A. Lind
bergh and the late DR. F. c. Meier, plant
pathologist of the Department of Agri-
culture. These two, in a series of ex-
periments. explored the air at various
heights by trapping spores for micro
scopic study. 1t was during a continua-
ton of this study that DR.. Meier was
lost last summer with the disappearance
of the China Clipper.
Working on the assumption that the
wheat rust spores are carried back south
by the winds from the north Dr.. Chester
is planning to explore the air over Okla
homa. The equipment used to trap the
spores In the upper air is rather simple
device. 1t looks like large paddle. At
the end of the paddle are microscopic
plates, where the recordings will be
made. The paddles are sealed in a germ
proof case when not in use. The plates
will be exposed at various levels.
Theories have been advanced that
wheat rust spores may remain in the soil
from one season to another, or that they
may be living in wild grasses. DR. Ches-
ter considers both these as unlikely In
the wheat growing season the period of
incubation for the spore is 10 days After
this time the series of mgrations with
the wind begins northWard Few ele-
ments of nature cause such severe loss to
the United States as a whole than these
spores. Last year they ruined approxi-
mately 10 per cent of the wheat crop. In
Oklahoma the loss was approximately Is
per cent.
Losses have been very greatly reduced
in Virginia, Maryland and Pennsylvania
during the past few years by eradication
of barberry bushes. These are known to
shelter the disease over winter. These
States, however, also suffer from spores
blown in from the wind.
Wheat growers will continue to suffer
heavy crop losses, Dr. Chester points
out, so long as the migration routes and
times of the spores remain unknown
When these are found it is highly likely
that some means of preventing the
movements may be found