With more carbon dioxide, lima bean plants grew faster and were eaten faster by cabbage loopers. In fact, the extra growth was about offset by the extra looper feeding.
ILLUSTRATION: MOTHER EARTH NEWS STAFF
The Seasons of the Garden column shares seasonal gardening information and tips with MOTHER EARTH NEWS readers.
Seasonal Gardening Research Briefs
Foam away frost? According to East
German experiments, an eight-inch layer of nontoxic,
biodegradable foam protects strawberry, tomato, bean and
potato plants from several hours of subfreezing temperatures
(even down into the teens). The product is not yet
Stretchy tree paint.Tree-Max, a paint
specially formulated to protect the trunks and lower
branches of fruit trees from sun scald, contains an elastic
material that allows it to stretch and grow with the tree.
The permeable paint is available from Associated Technical
Consultants, Toledo, OH.
Freeze herb pests. Dr. A.D. Tucker of the
Delaware State College Herbarium says that freezing
harvested herbs for 48 hours at 0°F should kill all
insect pests and egg clusters. Dried-on-the-vine raisins
are now feasible, at least in fairly arid regions. For
details, write to H.E. Studer (Dept. of Agricultural
Engineering, University of California, Davis, CA) for
a copy of his paper, "Raisin Production by Natural On
Death to multiflora rose. If you've ever
struggled against that invasive briar, multiflora rose,
you'll be glad to hear about rose rosette. This disease
causes deformed stems, altered leaflet development and
bright red spring shoots one year—and kills the
entire plant the next!
Cool compost, please. According to
research at the Ohio Agricultural Research and Development
Center, soil mixes containing materials composted at
moderate temperatures can help suppress damping off of
seedlings. However, compost cooked at high temperatures
(above 140 degrees Fahrenheit) can actually pro mote such fungus
diseases. Apparently, the beneficial microorganisms that
attack damping off are killed by the higher temperatures.
Thank you, tropics. Most bean varieties
are rather poor nitrogen fixers. But horticulturist
Frederick Bliss at the University of Wisconsin has
developed new kidney, pinto and white northern cultivars
that can fix up to 50 pounds of nitrogen per acre (the
equivalent of over 100 pounds of applied N per acre). Bliss
crossed commercial cultivars with native beans obtained
from the International Center for Tropical Agriculture in
Sprouts need calcium, too. Canadian
researchers have found that adding just about 1/4 teaspoon
of calcium chloride (available at drugstores) to every
gallon of water used to rinse mung bean sprouts can delay
stem collapse and decay for up to a week after germination.
Urban garbage goodies. Seattle is
promoting composting as the least expensive way to recycle
household organic wastes. The program includes literature,
demonstration sites, a master composter's
program—even a composting hotline. For more
information about community compost education programs,
contact the Seattle Solid Waste Utility, Seattle, WA.
Limas and Loopers
They grow faster and they get eaten faster. That sums up
the findings of entomologists at the University of
California, Riverside, who grew lima beans under conditions
of elevated levels of atmospheric carbon dioxide and then
introduced cabbage loopers. The motivation for this
research is the continuing increase (about 0.3% per
year) in the concentration of global atmospheric capon,
dioxide, mainly due to the combustion of fossil fuels.
Agricultural and horticultural researchers expect the
increased carbon dioxide concentration to affect plant
productivity, but they aren't sure to what extent.
Theoretically, more carbon dioxide should result in faster
plant growth. It should also reduce the ratio of nitrogen
to carbon in plant leaves, so that animal and insect
herbivores will have to eat more of the leaves to get the
same nutritional value.
The California research results agree with the theoretical
predictions: With more carbon dioxide, lima bean plants
grew faster and were eaten faster by cabbage loopers. In
fact, the extra growth was about offset by the extra looper
feeding. It looks like we might be headed for a frenzy of
accelerated crop production and consumption.
EDITOR'S NOTE: Greg and Pat Williams raise most of their own food on a small farm and publish HortIdeas, a fine newsletter on gardening research and products (available for $10 a year from G. & P. Williams, Gravel Switch, KY).