|
|
|
 |
Science Update
|
| New Species of
Leafhoppers Found in South America
A new insect species belonging to the leafhopper tribe Megophthalmini has been
discovered in the Andes Mountains of Tachira, Venezuela. It's the first record
of this subfamily being found in the New World south of Mexico. Of the 20,000
known species of leafhoppers, more than 170 transmit crop diseases. Many attack
U.S. crops such as corn, rice, citrus, peaches, tomatoes, potatoes, and sugar
beets. Farmers' efforts to control leafhoppers have been hampered by the
insects' seasonal migration—often from noncrop plants that harbor crop
diseases. The extent of this disease reservoir is not well known, because too
little is known about the leafhoppers' plant preferences.
These Megophthalmini leafhoppers—previously known only in North America,
Africa, and Europe—have novel traits that point to relationships to other
leafhopper subfamilies. Although the new species is not a crop pest, some of
its relatives are. Better understanding of its familial relationships can lead
to more accurate predictions of any leafhoppers' pest potential, but this task
has been hampered by major gaps in knowledge of various leafhopper groups
including the Megophthalmini.
Knowing an insect's identity is the first step in controlling it. And it helps
USDA's Animal and Plant Health Inspection Service intercept invasive
species—those not indigenous to the United States—at U.S. ports of
entry.
Stuart H. McKamey, USDA-ARS
Systematic Entomology Laboratory,
Washington, D.C.; phone (202) 382-1779.
Biofungicide Treats Apples and Oranges Alike
Apples and oranges are all the same to biofungicides. First introduced in the
United States 4 years ago via ARS patents, these nontoxic biological coatings
are replacing synthetic chemicals for controlling rot-causing fungi on apples,
pears, and citrus after harvest. Now, ARS has signed an agreement with the
Micro-Flo Company of Memphis, Tennessee, to finish developing next-generation
biofungicides for fruit packinghouses. Micro-Flo expects to have a product on
the market within 2 years.
Unlike earlier biofungicides, the new coating has a kickback effect that stops
fungi already having a toehold on the fruit. It combines two bioactive
substances with Candida saitoana yeast, which is innocuous to people but
a formidable competitor against fruit-attacking fungi.
The coating's bioactive substances are chitosan—a naturally occurring
fiber found in some weight-loss products—and a synthetic sugar used as a
glucose substitute. Chitosan acts as a natural fungicide and turns on defensive
enzymes in the fruit itself. It also forms a film on the fruit that holds in
carbon dioxide, thus increasing shelf life. The synthetic sugar tricks the
fungi into perceiving it as food—but they can't use it. Under the new
agreement, Micro-Flo and ARS scientists will optimize the coating's formulation
and fine-tune its application.
Charles L. Wilson, USDA-ARS
Appalachian Fruit Research Station,
Kearneysville, West Virginia; phone (304) 725-3451, ext. 330.
|
|
Toward Safer Fresh-Cut Tomatoes,
Melons
Most of the fresh-cut produce market's 20-percent annual growth is in
vegetables. While retailers have long sought a way to offer consumers fresh-cut
tomatoes and melons, they haven't pursued that market beyond local or regional
fresh-cut processing because of product quality problems and food safety
concerns caused by inadequate cold temperatures during distribution.
In the past, melons and tomatoes have been associated with Salmonella,
which heads the list of common causes of foodborne illnesses. About 40,000
cases of salmonellosis are reported annually, according to the federal Centers
for Disease Control and Prevention in Atlanta, Georgia.
Now ARS scientists have entered into a 2-year cooperative research and
development agreement with EPL Technologies, Inc., of Philadelphia,
Pennsylvania, to develop novel methods for killing or removing disease-causing
bacteria from fresh-cut fruits. Under the agreement, the scientists will seek
alternatives to common sanitizing agents, such as chlorine, that are used to
wash fresh-cut foods. This research should allow fresh-cut manufacturers to
expand their markets and make healthy fresh-cut products available to a larger
group. Successful introduction of these products will be a major boon to
growers and shippers.
Gerald M. Sapers, USDA-ARS
Plant Science and Technology Research
Unit, Wyndmoor, Pennsylvania; phone (215) 233-6417. |
|
"Science Update" was published in the
May 2000
issue of Agricultural Research magazine.
|
|
|
[Top]
|
|
|
|
Share/Bookmark
Printable Version
E-mail this page
