Aventis stumbles anew on Brazil soy market (UPDATE: recasts lede; adds context, background throughout) By Reese Ewing SAO PAULO, Nov 20 (Reuters) - The French-German biotech firm Aventis (NYSE:AVE - news) may lose its dominant position in the Brazilian soybean market after Brazilian farmers reported a bad batch of fungicide, only months after its bioengineered StarLink corn rattled world grain markets. Brazilian farmers said that last month's soy plantings failed because of a bad batch of Aventis fungicide that killed the germinating seeds, said grain analysts Safras e Mercado on Monday. Brazil's multi-billion-dollar soybean sector now faces another potential setback after enduring losses from a prolonged drought that parched farms the last two seasons. A bad batch of Rhodiauram fungicide may now undo the season's favorable planting. Key soybean farms in Parana, Santa Catarina, Sao Paulo and Mato Grosso do Sul states reported that seeds were not sprouting from their recent 2000/2001 crop plantings. ``The reason seems to be a toxic effect on seeds treated with some lots of the fungicide Rhodiauram, from the chemical company Aventis,'' said Safras in its weekly soybean report. Safras said the extent of the problem was not yet known, but the area treated with Aventis's fungicide should be substantially large. Aventis company officials in the United States and in Brazil could not be reached for comment. The chemical that stops fungus from forming on seeds in the ground has been widely used in Brazil in the past, over as much as 2.5 million hectares (6.25 million acres) of beans, or 20 percent of Brazil's total area planted to soybean. This latest problem comes on the heels of the company's commercially devastating debacle with its biotech StarLink corn, which found its way into U.S. human grain supplies. Some consumers reported the corn caused rashes, diarrhea and other allergic reactions. The U.S. Department of Agriculture had approved the Aventis' gene-altered corn only for animal consumption, but it turned up in taco shells and corn chips in late September. The subsequent consumer backlash is hurting U.S. corn exports to big buyers such as Japan and South Korea. Grain analysts said it would take years to remove the corn from U.S. silos earmarked for human food stuffs. Despite its problems, Aventis traded at all-time highs last week on the Paris CAC-40 exchange and closed Monday down slightly at 90.80 euros. Aventis shares were down nearly 4 percent, or $2-15/16, at $75-1/2, in trading on the New York Stock Exchange. Brazil is the world's second largest soybean grower after the United States and accounts for 20 percent of the world supply. Safras has forecast Brazil's soybean crop to reach 34.485 million tonnes in 2000/2001, an 8 percent jump over last year. Although the company guarantees the products it sells, wasted planting will still hurt the farmer. Safras said while they can still replant, higher operational costs and lower productivity will drain farmers' pockets.