A3o—Lancaster Fanning, Saturday, April 17,1902
Del. entomologist studies chemical warfare waged by plants
NEWARK, Del. If it weren’t
for their own defense stiategies,
the plants we know today probably
would have been gobbled up by
hungry insects long before they
reached their present state of
evolution. Yet people usually think
of plants that are preferred insect
hosts as susceptible or poorly
protected.
John C. Reese, entomologist at
the University of Delware
Agricultural Experiment Station,
disagrees with this assumption.
Actually, he says, even the most
susceptible plants are remarkably
well protected against insect at
tack. Finding out how they wage
war on insect enemies could help
geneticists develop varieties of
food crops which are more
productive and cost less to grow.
One way plants protect them
selves is by producing substances
called allelochemicals. These are
nonnutritive compounds, such as
alkaloids, which are synthesized
by one organism and have some
effect on another in this case, a
negative effect on plant-chomping
insects. Reese says he hopes to
isolate and identify some of these
compounds. If this can be done, it
might be possible to chemically
screen plant varieties for
resistance to major crop pests a
much more efficient method than
the time-consuming held trials
now used.
With the help of a $7OOO
University of Delaware Research
Foundation grant, the en
tomologist has been testing his
theory on the natural resistance of
plants to insects, using black
cutworm larvae, tissue from in
bred field corn lines, and an ar
tifical diet which favors larval
growth. He reported on this work
at the recent national meeting of
the American Chemical Society in
Las Vegas.
Results of his research show that
even fairly susceptible corn lines
are quite well defended against
cutworm attack. In fact, larvae
raised on the artifical diet grew
more than six tunes as well as
those reared on com leaf tissue.
He has been able to extract some
of the growth-inhibiting properties
of com seedlings. Incorporated m
an artifical diet, these substances
inhibit larval growth, proving that
at least some of the plant’s
protective strategy is due to
chemistry.
Reese found that cutworm
larvae are most affected by this
chemical defense during the first
48 hours after they hatch. He is
using this knowledge to increase
the sensitivity of his screening
method.
He also found that the larvae are
very susceptible to handling a
fact rarely taken into account
when such experiments are
designed. Because of this, he and
his assistants now place eggs,
rather than larvae, on the diet or
plants when screening is done.
Using this method of testing for
plant resistance to insect attack,
the entomologist says he may
eventually be able to chemically
screen as many as 1,000 to 2,000
UNIVERSITY PARK - With
Penn State’s annual Dairy Expo
just three weeks away, several
students and faculty members are
busy preparing for the day-long
show and subsequent banquet, on
Mayl.
The overall exposition chairman
is Logan Bower, senior in dairy
production from Blain, assisted by
Hooversville dairy production
major David Naugle. Show
manager is Brian Detwiler, semor
in dairy production from New
Enterprise, and his assistant is
Don Snyder of Pitman, junior in
agricultural economics and rural
sociology.
Special events for the day are
being planned by Martha Gregory,
junior in nutrition from Lititz. The
assistant chairman is David Lash,
sophomore in dairy production
Newton. Faculty advisors are
Lawrence D. Muller, and Thomas
F. Sweeney.
Judges for fitting and showing
competition will be Guernsey
breeders Peter Witmer of Willow
Street, and Benuta Snider Gable of
New Enterprise.
Also planned for “Show Day’’
are special events which include a
celebrity milking contest, various
milk “chugging” contests, and a
calf dressing contest. The com-
inbred corn lines during a single
winter season. Those which show
the greatest-promise can then be
studied more closely the following
growing season for their in
teraction with cutworm larvae or
other insects. This would greatly
simplify the search for resistant
plants.
The black cutworm is a major
pest of field com, as well as a
number of vegetable crops. It has
been know to destroy up to 95
percent of the com seedlings in
some fields and, according to
University of Delaware Extension
pest management specialist Mark
Graustem, it causes at least 2.5
percent of this crop to be replanted
PSU announces ‘Expo’ aides
plete exposition includes the an
nual Dairy Princess Contest April
12.
Holstein breed manager for the
Exposition is Sylvia Cooper, senior
in dairy production from Slippery
Rock. She is assisted by David
Stahl, senior iq dairy production
from Somerset; Robert McCarthy,
senior in dairy production from
Aaronsburg; and William Devore,
senior in dairy production from
Washington.
Show manager from Brown
U. of Del.
NEWARK, DEI. - Students at
the University of Delaware’s
College of Agricultural Sciences
are getting ready for their annual
Ag Day festivities. This popular
event takes place Saturday, May 1,
starting at 10 a.m.
Students and professors will be
on hand to answer gardening
questions, conduct tours of the
grounds and facilities, and let
visitors pet the animals. They’re
preparing a fine country dinner
a mouth-watering chicken bar
becue. From 1 to 4 p.m. visitors
can buy half a chicken, potato
each year.
More than 71 million acres of
field com are grown annually in
the U.S. at a value of ap
proximately $14.4 billion. Even if
only one percent of the crop is lost
to cutworms, this still represents a
loss of about $144 million.
Toxaphene is one of the most
frequently used insecticides for
controlling black cutworm larvae,
but it may be withdrawn from
commercial use because of the
recent discovery of its mutagenic
properties. Also, black cutworms
are more prevalent m no-till than
in conventionally grown com. *
As no-tillage practices continue
to increase, cutworm problems
may also increase substantially.
Swiss, Guernsey, Ayrshire, ana
Jersey breeds is Ken Kehr, junior
ip dairy production from Lit
tlestown. The assistant show
manager is Linda Kramer, junior
in dairy production from Fenelton,
along with Penny Smith,
sophomore in dairy production and
agricultural education, from
Mansfield.
Editor of the Penn State
“Dairyman,” the official catalog
and yearbook for the Dairy Science
Club, is Cindy Barto, senior in
Ag Day set for May 1
salad, roll and butter, homemade
dessert and beverage all for a
modest pnce.
The day’s events will include a
sheep shearing and wool weaving
contest; a petting zoo that features
a variety of clean, well-groomed
farm animals gentle enough for There will be crafts for children,
even young children to pet; a an egg toss, a hay bale toss and a
student beef show with halter- tug-of-war. There will be
broken heifers and steers trained educational displays on everything
by the contestants; horse from farm safety and solar energy
grooming and riding demon- to career opportunities in
strations; pony rides; and haynde agriculture.
This puts more pressure on plant
breeders to develop insect
resistant varieties.
The use of crop plants resistant
to insect attack is basic to the
integrated pest management
programs now being advocated in
agriculture. Such programs call
for the use of resistant varieties,
cultural and other biological
methods, as well as chemicals in
suppressing crop pests.
Resistant varieties don’t cost
more to grow, have few en
vironmental side effects, and are
very compatible with other control
techniques. Thus, they’re an ex
tremely important part of this pest
management package, concludes
Reese.
advertising from Pennsylvania
Furnace. Laura England, junior in
general agriculture of William
sburg, is the assistant editor of the
“Dairymen.” Publicity chairman
is Lisa Shirey, junior in
agricultural education from
Beavertown. Assistant publicity
coordinator is Marcia Minor,
freshman in agricultural business
from Washington.
Presentation of awards will take
place at the annual banquet May 1
at 7:00 p.m. in the Sheraton Inn,
State College.
tours of the University farm’s
animal, plant and research areas.
There will also be a plant sale, a
sick plant clinic, and flower
arranging contest, plus guided
tours of the college's ornamental
gardens, and demonstrations on
how to preserve flowers.