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hybrid material resistant to diseases, insects, drought,
and cold, and having improved sugar content and maturity
characteristics. Promising strains of cane developed
in the U.S. are being sent to India and crossed
with wild types. True seed of superior crosses of special
interest to U.S. sugarcane breeders are being sent back
to USDA for use in domestic breeding programs.
Parasites, Predators, and Pathogens of the European Corn
Borer.-A variety of parasites of this pest of corn have
been received in the United States from India and subjected
to preliminary study. A few have been released
for field trials. A species of wasp appears to have promise
and is being intensively studied.
Induced Sterility of Males of the Mediterranean Fruitfly.-
New methods of combating the Mediterranean friitfly
by induced sterility are being studied in Egypt. This
pest of fruit has invaded the United States on several
occasions and large suns of money have been spent to
eradicate it. Field trials of sterile male releases are under
way to determine the effect of this procedure in suppressing
populations of Medflies. Researchers are making
significant progress toward a biological means of combating
this pest.
A Study of the Hostplant-Vector and lostplant-Virus
Relationships of the Rough Dwarf Virus Diseaseof Corn.-The
maize rough dwarf virus and its insect carriers have been
found, by research workers in Israel, to have a much
Foodsfrom thefarms of
America provided funds to
support this floating hospital
in EastPakistan, specializing
in research into the prevention
and eradicationof cholera.
wider distribution than was previously suspected. In
addition to the Mediterranean zone, they have been
found in Central France, Czechoslovakia, Romania, and
Bulgaria. The disease represents a potential hazard to
North American corn production.
American hybrid maize varieties have been found to
be more susceptible than Old World types to this virus.
There has been some indication that barley, in addition
to maize, may be susceptible to the same virus. If this is
correct, then maize rough dwarf virus research will
eventually prove to be of even greater significance.
Growth of Trees in Swamps Related to Spacing of Drainage
Ditches.-Finnish scientists have found that drainage
ditches greatly increase the growth of trees in swampy
regions. Optimum depth and spacing is under further
study. There are millions of acres of swamp forests in
the United States in the northeast, the lake states, and
Alaska. The results of this Fin-ish study v.ill help
American forest managers to incr.,e yield at a minimum
cost.
Resin Production.-The factors which control the production
of resin in pines are not understood. Findings
by Spanish scientists provide a lead for investigating the
basis for resin production, thus enabling American
scientists attempting to stimulate resin production to
make further research gains.
Bark Beetle Attractant Identified.-Bark beetles of
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