Evening star., 1928-12-29

Continued From First rage
among potato tubers of the disease
| known as net-necrosis, Prof. A. II
Cilber of the Mcdonald College, Quebec
declared. connecting 1t with the wide.
spread ailment of potato plants caileo
leafroll. ...
Studies of the latest addition to tnl'
group of disease, which causes oe'
generation of potato tuberS ana plants
were reported by DR.. E. s. Scnuitz o.
the Department OF Agriculture ane
Reiner Bonde of the Maine Agrlcui'
tural Experiment Station.
The new disease is known as aplca
1eafroIl and causes a dwarfing OF the
ulants with a rolling of the upper leaves
The tubers are smaller than healthy
ones but are otherwise normal In ap-
pearance. It persists from year TO yeal
! when diseased tuberS are planted. Ine
most conspicuous symptoms appear toc
late to permit effective control.
Sweet Potato Diseases.
The widely destructive disease o.
sweet potatoes known as stem rot can
be controlled, DR.. r. F. Poole OF tne
North Carolina Agricultural Experiment
Station declared, by dipping healtny
sprouts into q mixture OF copper sui
phate. lime and water before planting
them in infected soil.
Means of controlling the leaf-molc
disease which attacks tomato plants ln
greenhouses we're described by A. q
Newhall and DR.. j. D. Wilson OF the
Ohio Agricultural Experiment Station
The fungus which causes the mold
they said, requires a high degree OF
humidity to develop sufficiently to
destroy the crop.
They have been able to overcome the
disease by installing forced air venti-
lation in green houses to remove excess
moisture. the extent of which can be
Judged from the fact that a fleld OF
tomatoes under June conditions may
give off 400 gallons an hour. Similar
difficulties have been encountered with
other crops grown in greenhouses DUR
ing Winter months, and the ventila-
tion method is expected to have wide
application.
The germ which causes fireblight on
apple, pear and similar fruit trees Is
spread by rainwater and not by insects,
as has been supposed, P. w. Miller OF
the Wisconsin Agricultural Expert
mental Station, told the society.
Cedars Control Diseases.
DR.. H. e. Thomas and w. D. Mills
of the New York Agricultural Expert
ment Station, asserted that the rust
diseases of hawthorn and ounce, which
also can affect apples, can be con-
trolled by removing all neighboring
cedars. The organism which cause
them. he said, must have cedar trees
on which to spend part of their lives
If they are to live long enough to do
any damage.
The old blue bottle that used to be
familiar container OF drugs and
medicines may soon be no more.
Experiments showing that this is the
poorest color of glass for preserving
many drugs from bad effects Of light
were reported to the American ASSo-
citation for the Advancement of Science
today, before the division of chemistry,
by Prof. II. v. Army OF Columbia Uni
versity.
DR.. Army reported that the drug
handling world has swung to amber as
better color, but that an investiga-
ton is under way to discover the really
best color, and that certain reds have
been found, in preliminary tests, to
have good protective values
Why the soil heaves and cracks pave
ments, was described to the American
Association for the advancement OF
science today by DR.. Stephen Taber, OF
the University of South Carolina.
1t is partly because ice in forming
toward itself additional moisture, which
enlarges the ice area and its power OF
thrust. This water drawing In Is called
molecular cohesion.