chemistry professor Richard R. Schrock and coworkers at Massachusetts Institute of Technology. The MIT initiators are superior to the Caltech initiator for olefin metathesis reactions other than polymerization. One investigator who has used the new Caltech initiator is polymer chemistry professor Kenneth B. Wagener of the University of Florida, Gainesville. "It's easy to make, easy to use, and fast in the chemistry it induces," Wagener says. "Grubbs has assembled and refined the best features of earlier systems to produce what we call in our group the SuperGrubbs." Steve Stinson
Bt Threat To Monarch Caterpillars Affirmed A study by Iowa State University scientists concludes that corn genetically engineered to kill the European corn borer can spread enough of its pollen onto nearby weeds to harm monarch caterpillars that feed on them. Researchers John J. Obrycki and Laura C. Hansen Jesse collected pollendusted leaves from potted milkweed plants placed inside and outside fields of conventional corn and fields of two varieties of corn engineered to contain a gene from the microorganism Bacillus thuringiensis (Bt). The gene produces a toxin expressed throughout the corn plant that kills the European corn borer. Monarch caterpillars were placed on the collected leaves in the lab. About 20% of the caterpillars exposed to pollen from the Bt corn died within 48 hours, and two-thirds had died by the fifth day of the experiment. No caterpillars died in the group exposed to pollen from conventional corn. The research was published in the online version of Oecologia, an ecology science journal (http://link.springer.de/ link/service/journals/00442/index. htm). "We conclude that the ecological effects of transgenic insecticidal crops need to be evaluated more fully before they are planted over extensive areas," Obrycki and Jesse write. Last year, researchers at Cornell University led by entomologist John E. Losey found in a lab study that some monarch caterpillars died when fed on milkweed dusted with high levels of pollen from Bt corn (C&EN, May 24,1999, page 7).This study engendered a storm of protests
against biotech crops, especially in Europe. But that study was highly criticized because the caterpillars were exposed to more corn pollen than would be expected underfieldconditions. By collecting milkweed leaves in and near cornfields,Obrycki and Jesse tried to duplicate field conditions more closely. The Biotechnology Industry Organization (BIO), a Washington, D.C.-based trade association, claims that the conclusions put forward by Obrycki and Jesse are not consistent with those of the broader scientific community. "Dr. Obrycki's research stands in the shadow of more than 20 independent studies by widely recognized scientific experts who have found that... Bt corn does not pose a significant risk to the monarch butterfly," says Val Giddings, BIO's vice president for food and agriculture. At this time, only one of the 20 studies has been published, however. Monarch caterpillars can be protected if six rows of conventional corn are planted on the perimeters of Bt corn
fields, Obrycki says. Currently, the Environmental Protection Agency suggests, but does not require, that a buffer zone be planted around Bt corn fields. "Planting buffer zones of Bt-free corn is an effective and practical way of protecting monarchs and other butterflies from toxic Bt pollen," says Rebecca Goldburg, senior scientist at the environmental activist organization Environmental Defense. EPA already requires farmers to plant 20% of their corn acreage in nonBt corn to slow the evolution of pests resistant to Bt toxins. Planting the 20% acreage "as buffer zones would be only a small additional step," she says. In part because of the furor over monarch butterflies, and in part because the European corn borer presented less of a threat this year, U.S. acreage planted in Bt corn dropped from 28 million acres in 1999 to 20 million acres in 2000. Two weeks ago, EPA extended the registrations of Bt crops through the 2001 growing season. Bette Hileman
Chemical Trade Surplus Slips In First Half Both exports and imports of chemicals crease in the chemical trade surplus, rose in thefirsthalf of this year over the which jumped more than fivefold from same period in 1999, according to the May's meager $182 million surplus. Commerce Department's Bureau of the This turn of events is reminiscent of July Census. But imports continued to in- 1999, when the trade balance fell into a crease faster than exports as U.S. manu- deficit for the first time in anyone's facturers contended with a strong dollar memory. Industry observers believe compared with other currencies, espe- these anomalies are most likely due to cially the euro. delayed or incomplete reporting to or by The latest data show exports of the government. Dyeing chemicals contributed the chemicals and allied products rising a very respectable 14.5% to a value of al- largest percentage increase in the trade most $38.8 billion through the first six months of 2000. But imports rose 18.7% to $35.2 billion, driving the chemical trade surplus down from 1999 by 15.5% to $3.55 billion. Trade ended the half on an up note with exports in June rising 21.7% from the same month in 1999 to a value of $7.11 billion. Imports in June rose 18.5% to $6.10 billion, giving a trade surplus of $1.01 billion, up 44.5%fromJune 1999. On a month-to-month basis, June exports were up 8.6% from May, while imports fell 4.2%. This Source: Bureau of the Census caused a huge monthly inAUGUST 28, 2000 C&EN
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