Deer could bring ticks to their doom in a new ARS- led experiment to fight Lyme disease, which is transmitted to people by the ticks. ARS and collaborating scientists began the 5-year Northeast Area- Wide Tick Control Project this fall at test sites in Connecticut, Rhode Island, New York and New Jersey. Tests in Maryland are also planned. Each site includes a residential area and has an abundance of white-tailed deer. The deer carry blacklegged ticks. The ticks' bite can infect people with the bacterium that causes Lyme disease. In the experiment, scientists will use more than 100 feeding stations, called 4-posters, to treat deer with amitraz, a chemical that kills ticks but doesn't harm the animals. Each station has a bin of corn and four, upright rollers--one at each corner. To reach the corn, deer must brush their head, neck and ears against one of the amitraz-application rollers. By August 2000, the scientists hope the tactic will reduce populations of immature ticks--called nymphs--at each test site by up to 90 percent. Nymphs are the tick growth stage that most frequently transmits Lyme to people. In 1996, more than 16,000 cases of Lyme were reported nationwide, most of those from the northeast and mid-Atlantic states.
Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX
John E. George, (830) 279-0339, jegeorge@ktc.com
Parasite Biology and Epidemiology Laboratory, Beltsville, MD
John Carroll, (301)504-8300, jcarrol@ggpl.arsusda.gov

Some Indianmeal moth strains have a built-in chemical protection against the insecticide Bacillus thuringiensis (Bt). That's because the moths lack a key enzyme that Bt needs to kill insects. ARS studies showed that moths without this enzyme survived while eating a Bt diet. Earlier studies showed that some of these insects adapt to the toxin by altering a receptor in the gut. Now, they've found yet another way for the moths to resist Bt. While no immediate solution is at hand, this new information allows scientists to re-think current management strategies that are based on a single mechanism of resistance. Bt is a natural soil bacterium that has been used for 35 years as an alternative to chemical insecticides. Indianmeal moths are among the worst pests in stored products, primarily attacking corn and peanuts.
Grain Marketing and Production Research Center, Manhattan, KS
Brenda K. Oppert, (785) 776-2780, bso@ksu.edu

A tiny parasitic fly could mean big trouble for corn earworms that ravage corn, cotton and other crops. Results from a 3-year pilot study indicate releasing the flies into a crop field can put a sizable dent in corn earworm numbers. ARS researchers conducted the study to explore the biocontrol potential of the half-inch- long fly, Archytas marmoratus. Corn earworms and fall armyworm caterpillars, its natural prey, are the most destructive insect crop pests in the Southeast. They cost farmers more than $1 billion annually in losses and chemical controls. A. marmoratus flies don't kill the pests directly, but use them as room and board for their maggot offspring. The fly deposits the speck-sized maggots on or near the caterpillar pests. The fly maggots burrow inside a caterpillar and feed on it as they develop. They pupate and emerge a couple of weeks later as adult flies that mate and repeat the cycle. In the pilot study, scientists released about 600 lab-reared adult flies per acre in corn fields in southern Georgia and North Carolina. They found fly maggots or pupae in up to 90 percent of the corn earworms they sampled later. Future studies will explore using standard and novel sprayer equipment to apply the fly maggots directly to plants.
Insect Biology and Population Management Research Laboratory, Tifton, GA
James E. Carpenter, (912) 387-2348, jcarpent@tifton.cpes.peachnet.edu

A new handbook written by ARS scientists makes it easier to distinguish crop-eating flea beetles from the helpful species that eat weeds. "The Handbook of Palearctic Flea Beetles" describes 57 genera and 30 species of flea beetles native to the Palearctic region-- Europe, northwest Africa and Asia north of the Himalayas. The information should prove useful to scientists who want to increase their use of flea beetles to attack weed pests. Some flea beetles are excellent natural controls for leafy spurge, a major problem in 29 Western States. Other flea beetles feed on important crop plants, such as tomatoes and potatoes, corn and mustard. ARS scientists--world experts on flea beetles --have spent over a decade researching and organizing more than 200 pages of information on this subfamily of insects. To better identify flea beetles and predict their behavior, the handbook provides information on morphology, taxonomy, geographic distribution, host plants and other data for each genus. The user-friendly manual has full-body drawings for each genus and nearly 400 other illustrations. It also has a new identification key for 30 species of Aphthona, the spurge-eating flea beetle genus. Handbook users might include pest management specialists, port inspectors, biocontrol researchers and entomology students with special interest in this economically important group of insects. The handbook is published by Associated Publishers of Gainesville, FL.
Systematic Entomology Laboratory, Natural History Museum, Washington, DC
Alexander Konstantinov/Natalia Vandenberg, (202) 382-1794/1792, akonstan@sel.barc.usda.gov

A quarter-inch-long weevil now chomping on weedy melaleuca trees in Florida's Everglades may be joined in the future by other helpful insects. About 1,600 of the Oxyops vitiosa weevils, native to Australia, were turned loose in 1997 at 11 melaleuca-infested sites in Florida. Recruitment of the weevil for the biological control battle resulted from more than a decade of scrutiny by ARS scientists who proved that this beneficial insect will voraciously eat melaleuca--and only melaleuca. Potential new recruits now undergoing testing include four additional insect species from the tree's native Australia--a leaf-damaging moth and fly, a sap- sucking psyllid, and a gall-forming fly. Tests from a Brisbane, Australia, laboratory run by ARS and the Australian government led to permission from U.S. authorities to import some of these candidate species into Florida for indoors-only tests. Melaleuca, a relative of the familiar bottle-brush plant, invades an average of 14 to 15 acres per day in central and southern Florida.
Aquatic Weed Control Research Unit, Gainesville, FL
Gary R. Buckingham, (352) 372-3505, grbuck@nervm.nerdc.ufl.edu

A genetically engineered insect virus could put the kibosh on the corn earworm's destructive appetite for crops. Ultimately, the altered virus could be developed as a biopesticide spray to protect corn, soybean and other crops. Corn earworms cost U.S. farmers more than $1.5 billion annually in crop losses and chemical control expenses. ARS researchers altered a natural baculovirus to make it more lethal to the pests. In its normal form, the virus infects the worm's gut cells to replicate and spread. But it generally doesn't kill the earworms fast enough to stop them from damaging plants. Scientists engineered the new strain using some of the insect's own hormone- making genes. The hormones normally help regulate the insect's development from caterpillar to moth. But infecting the insect with the altered virus leads to a hormonal imbalance. The imbalance makes the pest stop eating. Plus, the insect excretes much of its water. In temperature-controlled laboratory experiments, newly hatched insects infected with the virus generally stopped eating after 48 hours. By 20 days, only 3 percent had survived and pupated, compared with 100 percent of uninfected insects. ARS has filed for a patent on the appetite-stopping gene. The scientists plan greenhouse experiments and seek commercial collaborators for field studies.
Insect Biocontrol Laboratory, Beltsville, MD
Ashok Raina,(301) 504-9396, araina@asrr.arsusda.gov

A shiny black wasp from Asia called Lysiphlebia japonica might help cotton plants battle the cotton aphid, one of their worst insect enemies. As a biological control or natural enemy, the wasps could reduce growers' reliance on insecticides. ARS researchers in California, working with state and university colleagues, are evaluating the pinhead-sized wasp's prowess in attacking the aphid. The egg that a female wasp deposits inside an unlucky aphid will hatch; the wasp larva that emerges will feed on and eventually kill the aphid. The scientists are monitoring the wasps' progress in small outdoor research plots at Shafter, CA. If these tests succeed, the researchers could make larger test releases in other central California cotton fields next year. ARS entomologists in Orlando, FL, were first to import the helpful wasps to control citrus pests. They sent wasp colonies to California for the cotton aphid tests.
Horticultural Crops Research Laboratory, Fresno, CA
Raymond K. Yokomi, (209) 453-3021, ryokomi@.lightspeed.net

Cotton and other crop plants could be a step closer to better drought resistance, thanks to "borrowed" genes and bioengineering. Most conventional plants can't take up water once they dry out. But genes from a South African grass and the native star moss, Tortula ruralis, have been identified that may help these two plants do just that. Test plants transformed with two of these genes are being studied for their ability to recover from water stress. If the experiments succeed, the next step will be transforming cotton. Earlier research at the same lab produced the first workable system for inserting genes from foreign organisms into cotton.
Cropping Systems Research, Lubbock, TX
Melvin J. Oliver, (806) 746-5353, moliver@mail.csrl.ars.usda.gov

Applying pesticides to cotton after sunrise reduces beet armyworm populations by 96 percent. This finding from ARS field tests is significant because the beet armyworm costs U.S. cotton growers tens of millions of dollars in crop losses and pesticide expenses each year. Beet armyworm larvae generally prefer cotton leaves. And as larval numbers rise, older ones tend to enter the flowers. But traditional predawn pesticide applications kill only about 12 percent of the larvae in flowers. That's because the flowers are still closed, shielding the pests. Once the sun rises and the flowers open, the pests are more vulnerable. On the other hand, growers have two good reasons for applying chemicals before sunrise. First, winds are lighter, so there's less risk that pesticide spray will drift. Second, bees critical for pollination are still safely inside their hives. The scientists advise growers to coordinate after-sunrise pesticide applications with nearby beekeepers to ensure that hives are temporarily moved to safer locations.
Western Cotton Research Laboratory, Phoenix, AZ
David H. Akey, (602) 379-3524, dhakey@worldnet.att.net

A new ARS-developed synthetic diet for the Colorado potato beetle--the first of its kind--will allow researchers to rear the bug in a laboratory. This key research tool will enable scientists to identify better ways to control the pest. The new diet doesn't include foliage or potato extract. ARS scientists made the gelatin-like diet based on a chemical analysis of potato leaf nutrients. The gelatin is cut into tiny cubes and served to the bugs; the cube size increases as the bugs grow from larvae to adults. The uniform diet allows researchers to mix in and evaluate potential control agents. In lab tests, scientists found that adding high levels of tomatine--a glycoalkaloid found in tomato leaves--hinders the beetle's growth. The beetle, which feeds on potato plant leaves, is the most destructive potato crop pest. Until now, evaluating and developing alternative types of control were difficult for researchers because the pest is available only for a short period each year--most abundant in May, June and July.
Insect Biocontrol Laboratory, Beltsville, MD
John M. Domek, (301) 504-5689

Squelching summertime weeds near the crop field could give winter wheat farmers better control over the Russian wheat aphid in parts of the Great Plains, ARS scientists found. This aphid is a major pest of U.S. winter wheat and barley. It spends the winter primarily on these crops throughout its North American range--16 states and two Canadian provinces. From 1994 to 1997, ARS researchers monitored the pest in and near cultivated cereal fields in Oklahoma, Kansas, Colorado, Nebraska, Wyoming and Montana. After crops matured, they tracked the aphid's movement to nearby noncultivated host plants during summer--and its return to newly planted cereal crops in the fall. The scientists found that 10 grass species could sustain the pest during summer. Its favorite summer hosts: several noncultivated grasses, as well as volunteer wheat and barley plants growing within 27 yards of an infested cereal field. Volunteers can sprout from grain that escaped the harvester in the previous year. The most important of the noncultivated grasses are Canada wildrye, crested wheatgrass and squirreltail. All have large seedheads and long awns--bristle-like appendages on the seedhead. These structures provide protective niches for the aphid. Besides helping farmers improve their control over the aphid, the findings could aid in forecasting the next season's aphid populations.
Plant Science and Water Conservation Research Laboratory, Stillwater, OK
John Burd/Kevin Shufran, (405) 624-4231/4361, jdburd@ag.gov, shurfan@ag.gov

A new computer model could lead to significant savings for warehouse owners who store agricultural commodities such as peanuts, dried citrus pulp, corn and cocoa beans. The model helps warehouse owners pinpoint the right time to fumigate against almond moth infestations. To control these pests, warehouses are now routinely fumigated three to four times a year with phosphine at a cost of $20,000 per fumigation. The ARS-developed computer model warns owners when a warehouse's inside temperature and moisture conditions are conducive to moth development. If temperatures are too high, managers can use fans to cool the warehouse from 75 to 65o F--sufficient to thwart moth reproduction. The model has successfully completed trial runs with almond moth infestations in peanuts, corn and dried citrus pulp.
Grain Marketing and Production Research Center, Manhattan, KS
James E. Throne, (785) 776-2796, throne@usgmrl.ksu.edu

Last Updated: February 18, 1998
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