Vegetable and potato growers soon will have an effective new fungicide to add to their disease management arsenal. The U.S. Environmental Protection Agency (EPA) has accepted Reason brand fungicide for review as a reduced-risk fungicide. The product also is undergoing concurrent review with the California Department of Pesticide Registration (CDPR).

Bayer CropScience expects registration of the product in 2003 for lettuce, tomatoes, cucurbits, onions and potatoes.

Reason is a locally systemic, fast-acting foliar fungicide that stops disease development at more sites of action within the disease life cycle, providing more complete crop protection than key competitive brands.

It also acts against both the direct and indirect germination cycles of many key diseases for more effective and reliable control.

The active ingredient, fenamidone, acts by disrupting electron transport in the pathogen's mitochondria, thereby stopping diseases before they develop in the leaf tissue. This preventive activity, combined with a strong antisporulent effect, stops disease before it can spread to healthy leaf tissue.

“In field trials, Reason has provided a fast, consistently high level of control against oomycete diseases, such as mildews and blights,” said Rob Schwehr, Reason product manager. “The product moves through the leaf to protect new growth as it develops, making the material especially effective during periods of rapid plant growth and during times when rain disrupts a normal spray program.”

After application, Reason penetrates leaf tissue with translaminar movement to protect both the treated and untreated sides of the leaf. The product also protects new growth because it has very quick uptake within the plant and is locally systemic within the leaf tissue, which helps prevent both the development and progression of diseases in the field.

“Because it acts against more stages of disease development, we believe Reason will be an outstanding disease control option for growers throughout the season,” Schwehr said.

Reason will be registered to control lettuce downy mildew; cucurbit downy mildew and Alternaria leaf spot; and onion downy mildew and purple blotch; as well as early and late blights of tomatoes and potatoes.

Reason is not yet registered and not yet available for sale.