|
|
|
 |
Science Update
|
| A Push-Pull Answer to Asian
Lady Beetles
Homeowners aren't too happy when large numbers of multicolored Asian lady
beetles come inside in autumn. Even though Harmonia azyridis has
served well as an effective biological control against aphids and scale
insects since its introduction in 1916, its indoor congregation creates
a nuisance. So researchers have been looking at compounds that might repel
the beetles. Two compounds—camphor and menthol—that seem to
irritate the insects' chemosensory organs have shown the best results
so far.
Scientists think that using such repellent vapors could push these beneficial
beetles from their overwintering sites. Then the insects might be pulled
by pheromone lures into traps and released where they'd perform their
biocontrol function.
Eric W. Riddick,
USDA-ARS Biological
Control and Mass Rearing Research Unit, Mississippi State, Mississippi;
phone (662) 320-7382. |
Annie the cow: bioengineered to
have a gene for mastitis resistance.
(K9314-1) |
Transgenic Cow To Resist Mastitis
"Annie" is the first cow to be cloned with a gene for an agricultural
application. She was born in March 2000, a copy of a pure-bred Jersey
cow. Now that she's over a year old, scientists are starting to test her
milk for resistance to mastitis, a bacterial disease that costs U.S. producers
about $1.7 billion annually. It is often caused by Staphylococcus aureus
bacteria that destroy milk-secreting cells in cows' mammary glands.
|
| Researchers hope that Annie's
mammary glands will secrete a protein called lysostaphin that may help
her resist attacks from S. aureus. That's because they inserted
a gene for lysostaphin production obtained from a benign species of Staphylococcus—S.
simulans—that competes with its disease-causing relatives.
Antibiotics cure only about 15 percent of cows infected with S.
aureus. It is among the most virulent of mastitis-causing pathogens,
causing nearly one-third of all infections in cows. If the lysostaphin
works, Annie will have an alternative defense bioengineered right inside
her cells. The scientists are also looking for naturally occurring mastitis-resistance
genes.
Kevin Wells and Robert
Wall, USDA-ARS Gene
Evaluation and Mapping Laboratory, Beltsville, Maryland; phone (301)
504-8342.
Kit for Detecting Flesh-Eating Maggots
Screwworms consume the living flesh of their victims. They cause great
suffering in afflicted livestock and wildlife and cost producers millions
annually. They can also plague pets and people. Eradication programs have
eliminated this parasite from the United States, Mexico, and most of Central
America. But trade with and travel to and from screwworm-infested regions
make reinfestations a concern.
Scientists have developed a diagnostic field kit to quickly spot any screwworm
flies trying to sneak back in. Its use reduces from several days to a
few hours the time it takes to differentiate screwworm fly maggots from
those of similar fly species and to take action to contain them.
Screwworm's presence can be confirmed in 6 hours with the kit, which has
been found 99.9 percent accurate. That's thanks to a monoclonal antibody
that binds with a protein antigen in screwworm tissue samples. Speed and
accuracy of detection will make possible an appropriate response to a
suspected new outbreak. A commercial test kit could be available within
2 years.
Steven R. Skoda, USDA-ARS
Midwest
Livestock Insects Research Unit, Lincoln, Nebraska; phone (402) 437-5267.
Heat Your Home or Feed Your Livestock?
Burnable pellets made from cotton gin trash are in a testing phase. The
new, low-cost, patent-pending system that makes the pellets can also turn
gin trash into livestock feed, fertilizer, or mulch—in either pellet
or loose form. The pellet mill presses the trash and other ingredients
into cylinders 1/4- to 5/8-inch wide and 1/2- to 1-inch long.
In North America, more than 60 commercial mills already make over 610,000
tons of fuel pellets each year. They typically consist of sawdust and
ground wood chips. The new pellets would include those parts of cotton
plants—stems, branches, seeds, cotton boll parts—removed during
ginning. Adding a hot, gelatinized starch solution makes the mixture more
digestible as feed and acts as a glue and lubricant to ease the material's
flow through the equipment.
Early tests show these pellets to be more digestible than those already
made from cotton seed hulls. The research and development are funded in
part by Cotton Incorporated, Raleigh, North Carolina.
Gregory A. Holt, USDA-ARS
Cotton Production and Processing
Research Unit, Lubbock, Texas; phone (806) 746-5353.
"Science Update" was published in the August
2001 issue of Agricultural Research magazine.
|
[Top]
|
|
|
|
|
Last Modified: 02/18/2005
|
|
Printable Version
E-mail this page
