MYCOGEN RECEIVES U.S. PATENTS COVERING INSECT-RESISTANT SEED PRODUCTS, SUES MONSANTO, DEKALB, DELTA & PINE LAND FOR INFRINGEMENT

October 23, 1996

SAN DIEGO, Calif.-- Mycogen Corporation (Nasdaq: MYCO) received two broad U.S. patents covering Bacillus thuringiensis (Bt)-based pest resistance technology in plants yesterday (Oct. 22), and filed a patent infringement suit in Federal District Court in Wilmington, Delaware, naming three companies that are marketing seed products developed with that technology.

Mycogen's patents (U.S. Patent Nos. 5,567,862 and 5,567,600) contain broad process and composition of matter claims relating to modification of Bt genes for improved expression of pesticidal proteins in plants, introduction of those genes into plant cells, and to plants and seeds produced from cells transformed with modified Bt genes. Mycogen holds similar patents in Europe, Australia, New Zealand and South Africa.

Mycogen's suit claims that its patents are infringed by Bollgard ^TM cotton, marketed by Monsanto Company and Delta & Pine Land Co., Monsanto's New Leaf^TM potato and YieldGard^TM hybrid seed corn marketed by Monsanto and DeKalb Genetics. Jerry Caulder, Mycogen's chairman and chief executive officer, said Mycogen filed suit to secure its legal position but prefers a negotiated settlement to litigation.

"These are not new issues," Caulder said. "Almost two years ago, Mycogen received a U.S. patent for our method of making Bt genes more "plant like" to increase protein expression. These newly issued patents make it clear, as we have said in the past, that any seed product using that technology is covered by Mycogen's patents, regardless of when it was developed."

Caulder said that the companies named in the suit were notified today, and that Mycogen is prepared to discuss possible approaches for out-of-court settlements.

Mycogen introduced NatureGard^TM hybrid seed corn with Bt-based resistance to European corn borer earlier this year. Ciba Seeds, which holds a license from Mycogen, introduced a similar product under the trade name, Maximizer^TM.

Mycogen is a diversified agricultural biotechnology company that develops and markets technology-based products and provides crop protection services to control agricultural pests and improve food and fiber production. Mycogen Seeds develops and markets planting seeds for improved crop varieties with genetically enhanced insect-resistance and other value-added characteristics. Mycogen Crop Protection develops and markets environmentally compatible biopesticides and provides crop protection services to growers of high value crops in California and Arizona.

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