ngin - Norfolk Genetic Information Network
Date:  1 December 2000


Not just bad for exports but makes little difference to pesticide use and almost certainly harms non-target insects (taking together USDA's research with minnesota's, Iowa's and Cornell's). Effects on human health unknown. Apart from that a ground breaking technology!

Remember how they dismissed Losey's Cornell research on larvae and said they were never found inside the corn fields where the density would be greatest? Now  Minnesota's research shows milkweed in cornfields contain two to five times as many larvae or eggs as weeds elsewhere.

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Altered Pollen May Harm Monarchs - by Philip Brasher, AP Farm Writer
Associated Press. - Friday 1 December

WASHINGTON ) - Scientists concerned that pollen from gene-altered corn may be killing monarch butterflies wanted to know how much of the insect's favorite food, milkweed, grows on farms. They found more of the weed than they expected.

Half of Iowa's corn and soybean fields, and three-quarters of the roadside and pasture land in the state contain milkweed, the Agriculture Department said Thursday. Research by the University of Minnesota turned up similar findings in that state.

The concern is that pollen from the gene-altered corn is landing on milkweeds and killing monarchs.

"We didn't have a good idea whether there is a significant amount (of milkweed) in corn fields or near corn fields,'' said Douglas Buhler, who conducted the USDA research. "It provides the information that people can use to assess the potential impact'' of the genetically engineered

The corn, known as Bt, contains a bacterium gene that makes the plant toxic to moth larvae that are a major pest to farmers. An estimated 19 percent of the 80 million acres of corn planted this year was Bt.

Laboratory research at Cornell University showed that the pollen was toxic to monarchs, but it is still unclear whether the pollen is dense or toxic enough in cornfields when the butterfly larvae are feeding to be a threat to them.

An Iowa State University study published this summer suggested it was. One in five monarch larvae died after being exposed to the toxic corn pollen for two days, the study found, but even that research was partially conducted under lab conditions.

Farmers say the pesticides they use on conventionally bred corn are more of a danger to butterflies and other insects than the Bt crops.

In Iowa, milkweeds cover about 0.03 percent of the state's corn and soybean fields and 2 percent of other rural land, including roadside ditches and pastures, according to the USDA study. Corn and soybean fields account for 78 percent of Iowa's land mass.

The Minnesota researchers, who have yet to publish their study, counted butterfly larvae at five sites in the state this summer and found the caterpillars were more common inside than outside cornfields. Weeds in cornfields contained two to five times as many larvae or eggs as weeds
elsewhere, said Karen Oberhauser, who led the research.

It isn't clear why, although it could be because weeds grown in the fertile soil of the fields are healthier or because the butterflies have fewer predators when they are living among corn stalks, said Oberhauser.

"What this research says is that if pollen falls in densities that are high enough to harm monarchs that the monarchs are there,'' she said.

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