Contents

Science Update

Bees Take a Stroll for Biocontrol

Some honey bees powder their feet as they leave the hive to gather nectar from flowers. That's because ARS scientists have recruited these bees as couriers in a nonchemical war on insect pests. The scientists recently patented a device that forces bees exiting a hive to walk through a pan in which their feet and legs get coated with a mix of talc and a naturally occurring insect virus. This nuclear polyhedrosis virus doesn't harm the bees. But as they buzz from flower to flower, some virus particles get rubbed onto blossoms. Susceptible insect pests that visit those blossoms may get infected—and die. In tests in fields of crimson clover, the bee-dispensed virus killed 74 to 87 percent of corn earworm larvae.

USDA-ARS Insect Biology and Population Management Research Laboratory, Tifton, Georgia; phone (912) 387-2330.

Mysterious Pine Toxin Is Identified

ARS scientists have unmasked a toxin from ponderosa pine needles that can cause cows to abort. Tests pinpointed the culprit as isocupressic acid, a yellow, oily substance in the tree's needles. The discovery may be the first step to developing an antidote and other ways to protect pregnant cows and their calves. Ranchers and scientists have known for about 30 years that pregnant cows can suffer abortions, premature delivery, or post-pregnancy complications within days after grazing on ponderosa pine. The toxin problem costs western beef ranchers an estimated $20 million a year. The scientists are conducting follow-up studies lo see if other labdane diterpenes—the family of compounds that includes isocupressic acid—are toxic to cows.

Lynn F. James, USDA-ARS Poisonous Plant Research Laboratory, Logan, Utah; phone (801) 752-2941.

Computers Help Reap Bigger Soybean Yields

Mississippi Delta soybean grower Kenneth B. Hood is growing electronic soybeans again this winter. He can harvest a simulated crop every 3 minutes with an experimental computer model from ARS. By following the model's advice during the real soybean growing season, Hood and four other Delta growers have reported real-world soybean increases up to 29 percent since 1991. Scientists at ARS and Mississippi Slate University began developing the model, called GLYCIM, in 1978. The American Soybean Association recently funded an expansion of the testing to include farmers in Alabama, Arkansas, Louisiana, Missouri, and Tennessee.

USDA-ARS Crop Systems And Global Change Lab, Beltsville, Maryland; phone (301) 504-5806.

Citrus Acid Could Find Textile Role

Orange trees and other citrus furnish a natural alternative to formaldehyde-based chemicals used to finish dyed cotton fabric. Finishing is essential to produce shirts and other consumer products that will be smooth and wrinkle-resistant after washing and drying. ARS scientists have now shown that citric acid, long an ingredient in foods and cosmetics, produces satisfactory durable-press properties in dyed cotton fabric. When finished with the scientists' technique using a citric acid solution, dyed poplin cloth held its color and wrinkle resistance. ARS collaborated on the research with The Bombay Textile Research Association, Bombay, India.

Robert M. Reinhardt, USDA-ARS Textile Finishing Chemistry Research Unit, Southern Regional Research Center, New Orleans, Louisiana; phone (504) 286-4528.

Corn Grows Digital Ears

An electronic bumper crop of corn is always ready to harvest from a prototype computerized catalog developed by ARS and Iowa State University researchers. The catalog, Corn-Base, will help researchers and breeders select corn accessions with desired traits from ARS' North Central Regional Plant Introduction Station. The researchers adapted commercial software and wrote some of their own to store color video images of corn ears, plus text, on CD-ROM and other data storage devices. Currently, the text can be accessed through USDA's Germplasm Resources Information Network. Eventually, the video imagery will be accessible via modem.

USDA-ARS Plant Introduction Research Station, Ames, Iowa; phone (515) 294-3255

New Casaba Fights Off Mildew

Breeders can now obtain a line of mildew-resistant casaba melons. Scientists at ARS and the Georgia Agricultural Experiment Station developed the new germplasm, called C931. It is the only mildew-resistant casaba for the Georgia and South Carolina growing regions. In field tests, 80 to 90 percent of the new plants survived powdery and downy mildews without chemical fungicide. Susceptible melons were wiped out. A plant of C931 typically yields one to four melons, each weighing 4 to 6 pounds.

USDA-ARS U.S. Vegetable Laboratory, Charleston, South Carolina; phone (843) 402-5300.

"Science Update" was published in the January 1995 issue of Agricultural Research magazine.