To detect insects hidden in soil and the interior of plants, ARS scientists and colleagues have adapted acoustic techniques commonly used by engineers to predict mechanical failures. Traditional field searches for insects are often destructive, time-consuming, and labor-intensive. So researchers have been trying to find a more cost-effective and less destructive way to detect infestations. The acoustic technique uses sensitive instruments like accelerometers, soil-probe, microphones, and piezoelectric disks to pinpoint insect locations. These sensors convert vibrations into electrical signals. The portable sensors were found to detect insects within 180 seconds across distances of 10 to 30 centimeters, depending on the soil's composition and peak frequencies of the sound pulses. Those sound pulses were then averaged to create profiles for each insect. Under laboratory or ideal field conditions—with low levels of low-frequency background noise—insects within 30 cm were detected 100 percent of the time. Under adverse field conditions, the technique was 75 percent reliable.

Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL
Richard W. Mankin, (352) 374-5774, rmankin@gainesville.usda.ufl.edu

ARS scientists will test the effectiveness of combining remotely sensed images with pest-scouting data to develop variable insecticide prescriptions that may do a better job of controlling the tarnished plant bug. Cotton producers spend $75 million annually to control this pest. The new system uses multispectral imagery to draw a correlation between plant vigor and pest density. It relies on a digital camera, sensitive to different wavelengths of light. Mounted in an aircraft that flies over cotton fields at various altitudes, the camera records images that can be processed to display variations in plant vigor. ARS researchers have found that plant bugs are more common in areas with more vigorous plants. This combination system is not only better at locating a variety of pests, but also gives growers a more cost-effective method of controlling the pests by improving the placement and timing of pesticide applications. Rather than spray an entire field at one rate, this system allows growers to vary their coverage. Unsprayed areas can act as safe havens for a variety of beneficial insects, which can then repopulate the field after spraying. This all translates into less chemical usage.

Crop Science Research Laboratory, Mississippi State, MS
Jeffrey L. Willers (662) 320-7383, jwillers@ra.msstate.edu

Raspberry plants that naturally resist bushy dwarf virus may soon be available. ARS scientists in Corvallis, OR, and Agritope, Inc., of Portland, OR, are genetically modifying the most popular raspberry variety grown in the Pacific Northwest to give the plants this resistance. The virus causes small, crumbly fruit unsuitable for use as whole berries. Infection spreads rapidly through a field, and growers often must remove the plants, fumigate the soil, and start over every 5-year cycle. That means fewer domestic raspberries and higher costs for consumers. The scientists are using genetic material from the virus to induce resistance in the raspberry plants. They're trying three strategies to find the best approach. One interferes with the virus' ability to replicate itself. Another alters and inserts a gene from the virus that prevents its spread from cell to cell. The third would have the plant make a small piece of viral RNA that doesn't make any protein and so becomes targeted by the plant for degradation. Researchers hope to refine the best strategy and provide breeding lines to growers within 3 years. They should also be able to use the results to incorporate virus resistance into other cultivars of raspberry, blackberry, or black raspberry.

Horticultural Crops Research Laboratory, Corvallis, OR
Robert R. Martin, (541) 750-8794, martinrr@bcc.orst.edu

Distinguishing the good bug from the bad bug just became more precise. A newly revised catalogue of known stilt bugs worldwide has eliminated previous errors and adds two overlooked species. True bugs are a common and diverse group of insects that are both pests of crops and beneficial predators. The family Berytidae is a small but diverse group of true bugs that get their common name, "stilt bugs," from the long, slender legs and antennae of many species. Many stilt bug species have been implicated as pests of crops such as cacao, tobacco, and tomato. But several others are important predators, feeding on aphids, hornworm eggs and larvae, leaf-hoppers, thrips, and other pests. In February 1998, the ARS true bug experts published a world catalogue of stilt bugs that treated 36 genera and 169 species and contained nearly 200 host-plant records. Since then, feedback from several colleagues has helped to discover and correct several errors, like minor misspellings and the omission of species, for the forthcoming catalogue of stilt bugs of the Palearctic Region—the geographic region that includes the northwest coast of Africa, Europe, and Asia north of the Himalaya Mountains. These corrections supplement the world catalogue and include the two overlooked species. This information is of great importance to other researchers, including biocontrol workers who need an accurate, comprehensive summary of the literature treating stilt bugs and their distribution.

Systematic Entomology Laboratory, Washington, DC
Thomas J. Henry, (202) 3382-1780, thenry@sel.barc.usda.gov