A new ARS-developed Mediterranean fruit fly lure being tested in Florida may help keep this pest at bay by catching females before they can lay eggs. The female medfly, about the size of a housefly, can produce up to 800 eggs in her 30-day life span. So far, the pest has caused trouble in isolated outbreaks, but has not become endemic to the mainland United States. Until now, the only widely available traps use a male-targeted synthetic lure. ARS' new three-component lure uses ammonium acetate, putrescine, and trimethylamine. In the tests, 50 to 90 percent of the medflies captured in traps baited with the new lure were egg-laying females. The new lure has also proved less appealing to sterile male medflies than existing traps. That's an advantage in programs—such as one this past summer in the Tampa, FL, area where the new lure is undergoing field tests—that release sterile male flies as a part of a medfly eradication program.
Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL
Robert Heath/Nancy Epsky, (352) 374-5735/5877, bheath@gainesville.usda.ufl.edu, nepsky@gainesville.usda.ufl.edu

Overhead water sprinklers in orchards can cut fruit injury from codling moths by 60 to 90 percent—a bonus just discovered by an ARS scientist. Apple growers in Washington use the sprinklers to cool fruit during hot spells. That improves fruit quality and color and reduces sunburn. Uncontrolled, codling moths can wipe out entire orchards. The ARS scientist noted that the water disrupted moth flight, egg laying, and egg and larvae survival from July to September. The down side: The water might leave unsightly mineral deposits on the apples and a slight reduction in fruit size if growers don't watch water quality. Using canal water or treating well ater to lower acidity can minimize this damage.
Fruit and Vegetable Insect Research, Wapato, WA
Alan L. Knight, (509) 454-6550, aknight@yarl.gov

A harmless fungus and a touch of commercial fungicide knock out fungal pathogens that kill cotton seedlings. By using the beneficial fungus Trichoderma virens, ARS scientists say, growers can reduce reliance on chemical fungicides and still dramatically cut seedling losses. In a 3-year field study in California and across the southern Cotton Belt, the scientists coated cotton seeds with the harmless fungus and with the fungicide metalaxyl. The result: 85 percent of the seeds germinated into seedlings that survived even though the fields were infested with a variety of fungal disease pathogens that normally attack the seedlings. Without treatment, only 25 percent germinated. In 1995, cotton producers in six major cotton-producing states applied 719,000 pounds of fungicides to control seedling diseases. Seedling diseases that year caused $1.9 million in losses in the U.S. cotton crop. Seedling disease pathogens include Rhizoctonia solani, Pythium ultimum, Thielaviopsis basicola, and Fusarium solani.
Southern Crops Research Lab, College Station, TX
Charles R. Howell, (409) 260-9232, howell@acs.tamu.edu

A new, portable insect sampler dubbed the "KISS" —for "keep-it-simple sampler "—helps farmers and crop consultants measure insect populations in cotton, soybeans, corn, and other row crops. Knowing how many pests are in the field can let growers know whether pesticide or other controls are needed. ARS researchers designed the KISS from an engine-driven leaf blower. It generates 150-mph winds that dislodge pests from crops and blow them into a net attached to the nozzle. Preliminary field tests indicate "KISSing" is 10 times more efficient than hand-collecting boll weevils in early-season cotton. Boll weevils cause $330 million in cotton losses each year.
Areawide Pest Management Research, College Station, TX
Kenneth R. Beerwinkle, (409) 260-9519, k-beerwinkle@tamu.edu

Mite feces are a dead give-away that honey bee hives are infested with a parasite that's causing devastating damage in some areas of the United States. Now, with a simple new field test developed by ARS, beekeepers can quickly determine if their hives are infested with varroa mites. Then they can act quickly to control them. Current tests for varroa mites are time-consuming and expensive, and may require pesticides. But ARS researchers found that even very low infestations of this pest can readily be detected by the brilliant white specks of its feces. Known as Varroa jacobsoni, varroa mites originated in Asia and were first found in the United States in 1987. They suck blood from immature bees, mainly those in the last pre-adult stage. During a 10- to 12-day feeding period, female adult mites and offspring defecate on the horizontal brood cell wall just above each developing bee. The white feces can easily be seen if a brood comb is removed and inverted under bright sunlight. Varroa and other mite species have destroyed 80 percent of commercial beehives in some areas of the United States in recent years.
Carl Hayden Bee Research Lab, Tucson, AZ
Eric H. Erickson, (520) 670-6481, ehejr@ccit.arizona.edu

A natural fungus can control sicklepod, a major weed in soybeans, cotton, and peanuts in the southern United States. ARS researchers formulated spores of the fungus, Colletotrichum gloeosporioides, into a spray mixture with corn oil and water. Two sprays killed 95 percent of newly emerged sicklepod weeds in soybean plots. More than 3 years of field tests showed an overall sicklepod reduction of 90 percent. ARS has patented use of the fungus and stored samples of strain NRRL 21046 at the ARS Culture Collection in Peoria, IL. ARS is seeking industry cooperators to develop the fungus commercially as a biological alternative to chemical herbicides. (PATENT 5,529,773)
Southern Weed Science Research, Stoneville, MS
C. Douglas Boyette, (601) 686-5217, dboyette@ag.gov

Images of fungicide crystals scattered like snowflakes across a plant leaf can now be made using new technology developed by ARS scientists. The technology—dubbed Electron Beam Analysis (EBA)—combines scanning electron microscopy, X-ray micro-analysis, and digital imaging to produce 100,000-times-larger-than-normal images of pesticides. Each chemical has its own unique shape and chemistry, so scientists can check plant leaves to see which product was used, where it landed on the leaf, and how much of the leaf surface was covered. Digital images are scanned into and stored in a computer for future reference. This information can help scientists pinpoint the most effective control agents and improve recommendations for reducing pesticide usage in food and field crops.
Application Technology Research Lab, Wooster, OH
Charles R. Krause, (330) 263-3672, krause.2@osu.edu

A new lab diet is in the works for producing parasitic wasps that can help U.S. growers biologically control the Colorado potato beetle and reduce the use of chemical insecticide. Each year, this beetle costs U.S. eggplant, tomato, and potato growers an estimated $150 million in losses and insecticide-related expenses. A promising natural weapon against the beetles: Female Edovum puttleri wasps that lay their eggs inside the beetle's eggs, preventing the pest from hatching and becoming a wormlike larva that feeds on plants. But the wasps, native to South America, need a helping hand from science if they are to become widely available biocontrols in the United States. Using real beetle eggs to lab-rear millions of wasps would be prohibitively expensive. ARS researchers have devised an artificial diet that mimics the beetle egg's yolk-like contents. The chief ingredients are chicken egg yolk, powdered milk, and insect blood called "hemolymph." The researchers also developed artificial "beetle eggshells," a parafilm plastic membrane that contains enough diet to nourish a wasp larva until it's ready to emerge as an adult. Releasing adult wasps to attack real beetle eggs in crop fields wouldn't completely eliminate the need for insecticide. But growers could cut the number of sprayings. The scientists' goal is to make the commercial cost of lab-rearing Edovum affordable to insectaries that would sell the wasps to farmers.
Insect Biocontrol Lab, Beltsville, MD
Dale Gelman/Jing Hu, (301) 504-8909, gelman@asrr.arsusda.gov

A Brazilian fly that attacks fire ants could be part of a new, environmentally friendly strategy to control the pests. Fire ants infest millions of acres in the southern United States. ARS scientists made the first outdoor releases of the predatory flies, called phorid flies, in Florida in July. The flies zero in on a fire ant and—in a split second—dive-bomb it, pierce its outer cuticle; and deposit an egg inside the pest. The egg develops into a larva that migrates into the ant's head. Although the ant's head soon falls off, the young fly continues to mature inside it. Phorid flies attacks only fire ants and pose no threat to other insects, wildlife, or humans. The Florida releases of phorid flies followed quarantine studies dating to 1994. ARS scientists also are examining other potential biological controls for fire ants. Among the candidates: Thelohania solenopsae, a microbe that infects fire ants with a slow-acting disease that eventually destroys the ant colony, and Solenopsis daguerrei, a parasitic ant that invades the ant colony, attaches itself to the queen and eventually starves her.
Imported Fire Ant and Household Insects Research, Gainesville, FL
Sanford D. Porter/David F. Williams, (352) 374-5914/5982, sdp@nervm.nerdc.ufl.edu, dfw@nervm.nerdc.ufl.edu

Last Updated: October 28, 1997
Return to: Quarterly Report Table of Contents