Report on the Agricultural Experiment Stations, 1954 Page: 51
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than in other kinds of buckets. All buckets other than plastic were highly contaminated regardless
of position onthe tree. At the end of the season when contamination was extremely
high in conventional buckets, no organisms were present in plastic bags. Experiments are
under way to determine why organisms do not live in maple sap collected in plastic bags.
Keeping evergreen seedlings healthy
A few years ago a little-known fungus disease almost wiped out the production of
white pine and Douglas fir seedlings in Delaware. Then the Delaware station developed
a treatment which now provides a record production of seedlings. Using a combined
treatment of soil fumigation and foliage spray, a double-barreled method was found
for protecting conifer seedlings from the time of germination until the seedlings leave
the plant bed 2 to 4 years later. The treatment has also increased the growth rate of
young evergreens. Being free of parasites, the white pine and Douglas fir seedlings grow
as rapidly in 2 years as they did formerly in 3 or 4 years. Although the fungus, Cylindrocladium
scoparium, attacks northern conifers such as white and red pine, it does
not harm southern conifers such as loblolly pine.
Bacteria Assimilate Carbon Dioxide
Studies at the Iowa station showed that heterotrophic forms of life (those that do
not manufacture their own food) assimilate carbon dioxide, the process being similar
to that taking place in photosynthesis. Through the use of radioactive carbon, C13 and
C14, it was demonstrated that assimilated carbon dioxide was used not only to form
carbohydrates and acids but also in the formation of amino acids. Assimilated C1402 was
found to be used to form leucine, valine, methionine, proline, glutamic acid, glutamine,
citrulline, threonine, cysteine, ornithine, histidine, aspartic acid, tyrosine, and probably
arginine--all amino acids probably essential in life processes.
Freezing Micro-organisms
Bacteria and viruses are being quick-frozen to -300 F. by the Wisconsin station to
simplify the use of the electron microscope in studies of microscopic organisms. Materials
must be dried before they can be examined with the electron microscope because
the viewing chamber is under a high vacuum. Ordinary air-drying or heat-drying
distorts the shape of testing particles. By the new technique, very tiny droplets of the
bacteria or virus are sprayed onto blocks held at -300. The droplets freeze as soon as
they strike the surface. The blocks are then put into a vacuum chamber which dries
away the ice surrounding the specimen and prepares it for study under the electron
microscope. This technique should lead to more precise studies of related organisms,
as shown by the tobacco mosaic virus previously thought to be rod-shaped, but now
shown to have a hexagonal shape in cross-section.
CONTROL OF DESTRUCTIVE INSECTS
Protecting Growing Grain
Armyworm control saves one-fourth of grain crop
Missouri station research on insects has been directed largely toward service to
Missouri farmers in pest control. During one year armyworms invaded the entire State,
but they were most severe in the southerntwo-thirds. In this area it was safely estimated
that armyworms reduced grain yields (wheat, barley, oats)by 25 percent where the fields
were not treated. Some 7-1/2 million acres of grain crops and pastures were sprayed at
a cost of $2 per acre. With a conservative estimate of 30 bushels per acre yield of grain
and a $2-per-bushel value for the grain protected by destroying the insect, the recommended
practice of spraying for armyworm control produced an estimated saving to the
farmers of the State of $97,500,000 in a single year. Also, the new methods of chemical
control are easy to apply and save money in labor required for application.
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United States. Office of Experiment Stations. Report on the Agricultural Experiment Stations, 1954, book, April 1955; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc5988/m1/55/: accessed April 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.