Extension Ag Update
January/February 2002
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Research Results

Bt Corn Poses "No Significant Risk" to Monarchs

Kim Kaplan, ARS News Service, USDA, (301) 504-1637, Kaplan@ars.usda.gov


A consortium of federal, university and industry scientists led by the Agricultural Research Service has completed two years of research to answer the question: Does Bt corn pose a threat to monarch butterflies? The answer, supported by science, is that there is no significant risk. Bt corn is corn to which genes from the bacterium Bacillus thuringiensis have been added so the plant naturally produces proteins that protect it from insect pests such as the European corn borer. The research found that Bt corn pollen levels usually had to be more than 1,000 grains per square centimeter to have any negative impact on monarch caterpillars, let alone mortality. Scientists have concluded that less than one percent of the time are monarch caterpillars in the environment exposed to levels that even come close to that magnitude.

ARS entomologist Richard Hellmich is already planning the next round of investigations. He hopes to extend the consortium's work this summer with new collaborative studies, especially field studies, to look at whether there are any effects on monarch caterpillars from long-term or chronic exposure to Bt corn pollen. While the data already accumulated show Bt corn pollen does not pose a threat to monarch populations, these new studies should indicate if any minor effects are possible and the nature of those effects if they occur. ARS entomologist Leslie C. Lewis is planning to extend the work to look at whether Bt corn has any impact on non-target ground insects such as beetles. Hellmich and Lewis are both with the ARS Corn Insects and Crop Genetics Laboratory in Ames, Iowa.

Profits Possible from Pastured Poultry

Researcher: Steve Stevenson, Center for Integrated Agricultural Systems, 1450 Linden Drive, University of Wisconsin, Madison, WI 53706, (608) 262-5202; gwsteven@facstaff.wisc.edu

Wisconsin's pasturelands - long the land of black-and-white dairy cows -can also support grazing poultry. Properly managed and marketed, pastured poultry can turn a profit for farm owners, a University of Wisconsin-Madison study has shown. The benefits of a pastured poultry operation include low capital investment and the potential to start small and expand over time, according to Steve Stevenson, a researcher with the Center for Integrated Agricultural Systems at the UW-Madison. One person can run a small operation, and kids can help. In addition to building soil fertility and providing sustainably produced meat, the poultry operation can attract customers for other farm products.

CIAS researchers studied pastured poultry operations on five. The farmers had three to 10 years of pastured poultry experience, and most produced fewer than 1,000 birds per year. Farmers charged an average of $1.90 per pound for their chickens, selling them from the farm, at farmers markets, and to restaurants. The average net return per bird for all farms was $2.43, ranging from $7.05 to a $2.82 loss. Varying levels of managerial experience, wide differences in feed costs, and one case of chick loss in a brooder fire accounted for much of this variation. The goal of the operation - profits from the chickens, or attracting customers or building soil fertility — also influenced the returns, Stevenson says.

On these farms, a typical pastured poultry pen housed 75 to 100 meat chickens, placed in the pen at 3 to 4 weeks of age and butchered at 8 to 14 weeks. The floorless pens, roofed with plywood and measuring 10 feet by 12 feet by 2 feet, were slid to fresh pasture daily. The birds also received water and a grain ration. Using data from the farms they studied, the researchers developed models for a 1,000-bird supplementary enterprise and a 5,000 bird primary enterprise.

The 1,000 bird operation showed an annual net return to labor and management of just over $5,000 after five years of operation and building management skills. The four-month production period required 20 to 22 hours of labor per week, and the researchers estimated that an efficient farmer could earn $10 to $15 per hour. The 5,000-bird model showed annual net returns to labor and management of more than $18,000 in its tenth year. The six-month production period required 35 to 42 hours of labor per week, and the researchers estimated that an efficient farmer could earn $12 to $18 per hour.

There's a learning curve for the pastured poultry operators. One experienced farmer spent just 10 minutes per chicken from chick to processed bird; a less experienced operator worked for more than an hour per chicken. Feeding and watering birds and moving pens accounted for most of the work. Most farmers reported using some family help or hired labor. Processing poses the biggest obstacle to pastured poultry, farmers in the study reported. They were concerned about both the availability of licensed processors and the quality of processing. In Wisconsin, farmers are allowed to slaughter and sell up to 1,000 chickens per year on the farm. To sell more than 1,000 birds per year, or to sell to restaurants, producers must have the birds butchered at a Type 29 state-inspected plant; there are only two such plants in Wisconsin. Farmers in this study paid $2.75 per bird for processing at Type 29 plants, and costs are expected to increase. Stevenson notes that Illinois recently raised its on-farm processing limit to 5,000 birds; a similar increase in Wisconsin would improve the processing economics for farmers. (Source: Agricultural and Consumer Press Service, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 440 Henry Mall, Madison, WI, (608) 262-1461)

Samples harvested at 14 percent were not dried further. Stress cracks in the samples were measured as an index of the effect of drying severity. The dried samples were scanned with an Infratec 1229, that uses near infrared transmittance. Extractable starch yields were predicted using an equation with an R2 of 0.81, and SECV of 1.33. The starch was studied for the effects of high drying temperature on elatinization using a differential scanning calorimeter (DSC 2920), an electron microscope, and with water activity measurements.

The results indicated that the two harvest moistures were significantly different, with the 25 percent harvest moisture having higher starch yields, than the 30 percent corn. Corn dried at temperatures of 50 and 70°C had significantly higher starch yields than those dried at 85 and 100°C.

Sprays, Trap Promise to Slash Insecticide Use in America's Corn Belt

Don Comis, (301) 504-1625, comis@ars.usda.gov, Source: ARS News Service, USDA

While Agricultural Research Service scientists are not about to satisfy a plant pest's craving for pumpkin by serving pie, they are only too happy to serve a family recipe to die for. The ingredients of that recipe, including cucurbitacins and other chemicals from the pumpkin and gourd or cucurbit family, attract corn rootworm beetles. One of these ingredients is in three new, low-insecticide bait sprays and a monitoring trap for the beetles.

These commercial products have emerged from a 6-year joint ARS- university research and demonstration program in the Corn Belt. The bait sprays are CideTrak, made by Trece, Inc. Salinas, Calif.; Invite, made by FFP Agriscience, Inc., of Eustis, Fla.; and SLAM, made by MicroFlo, of Memphis, Tenn. The trap is the Pherocon Corn Rootworm Trap, made by Trece.

The trap lures beetles with volatile plant chemicals. It enables farmers or consultants to make sample counts of the beetles to decide when the numbers are high enough to warrant spraying with CideTrak, Invite, or SLAM. The baits are sprayed aerially on corn leaves where the beetles eat. The sprays form drops containing cucurbitacins and insecticide. The cucurbitacins cause the beetles to feed almost exclusively on the drops, so they ingest a lethal dose of insecticide. CideTrak and SLAM get their cucurbitacins from wild buffalo gourd root powder, while Invite relies on a Hawkesbury watermelon juice ingredient.

The actual active insecticidal ingredient in the three sprays is an ounce or less per acre, which is 95 to 98 percent less than in conventional sprays. The bitter cucurbitacin doesn't appeal to other insects, so it is safe for bees and other beneficial insects. The musky smell released when a cantaloupe is sliced comes primarily from cucurbitacin.

Relay Intercropping of Soybeans and Wheat

Jim Beuerlein, Agronomist, Ohio State University, (614) 292-9080, beuerlein.1@osu.edu and Tony Vyn, Agronomist, Ohio State University, (765) 496-3757, tvyn@purdue.edu

Ohio and Indiana farmers who practice relay intercropping of soybeans and wheat can choose from an array of wheat varieties that perform well in wider-row spacing, saving on equipment and seed costs. Wheat row spacing normally is 7.5 inches wide, said Jim Beuerlein, Ohio State University agronomist. But in studies conducted by Beuerlein and Purdue University agronomist Tony Vyn, certain wheat varieties performed just as well when row spacing was widened to 15 inches.

About two dozen wheat varieties were analyzed for their performance in Ohio and Indiana. The purpose of making the rows wider than normal is for the machinery to get through, so you can get more light coming down into the canopy to help the soybeans grow," Beuerlein said. Beuerlein and Vyn grew wheat varieties in both 7.5- and 15-inch row spacings, and compared yield, test weight and a variety of agronomic characteristics such as height and heading date. Beuerlein found that varieties that perform well in wide rows tend to be either tall by nature or grow tall because of favorable weather; and exhibit a nonerect growth habit that compensates for skips in the row or low population.

The research showed that wheat normally grown in 15-inch rows produces 5 percent to 15 percent less yield than wheat grown in 7.5-inch rows, but the lower yield from wide rows is partially offset by reduced seed costs, Beuerlein said. "When growing wheat in 15-inch rows, a farmer only has to use half as much seed per acre," Beuerlein said. "So, for example, if a 7.5-inch row has a two-bushel seeding rate, the farmer has saved one bushel at $12 a bushel for seed. He may lose four bushels of grain in yield, but at a grain cost of $3 per bushel he can still make the same profit. One bushel of seed has the same value as four bushels of grain." Seeding rates are significantly lower in 15-inch rows, Vyn said. He added that plants in the wider rows appear to be somewhat shorter than wheat in narrower rows.

"We observed that it is important to keep seeding rates at 850,000 seeds per acre in 15-inch rows," Vyn said. "That's much less than the traditional seeding rate in 7.5-inch rows of 1.3 million to 1.5 million seeds an acre. "We also found that wide-row wheat is less likely to lodge even with high nitrogen fertilizer rates." Wider-row spacing saves on equipment costs, because fewer seed meter units are necessary on the drill, Beuerlein said. "Farmers are looking for anything that will reduce production costs."

The relay intercropping process usually involves planting wheat in October, then interplanting soybeans the following year in late May or early June. Even earlier soybean planting dates are possible with polymer-coated seeds that delay soybean emergence. The OSU-Purdue data indicates both crops in an intercropping system perform well. "In many ways we are not sacrificing wheat yields in order to gain the potential of 30-bushel-an-acre relay soybean yields in areas that are traditionally not suited for double-crop beans," Vyn said.

Source: Candace Pollock, Associate Editor, OARDC Research Services, Ohio Agricultural Research, and Development Center, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, (330) 202-3550, pollock.58@osu.edu