Fungicides Taking Final Steps

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When Asian soybean rust first surfaced in the U.S. in November 2004, one of the most pressing concerns was having enough fungicide material available for soybean producers. Going into the 2005 growing season, EPA had approved full registration (Section 3) for soybean rust for chlorothalonil (Syngenta‘s Bravo and Sipcam Agro‘s Echo), pyraclostrobin (BASF‘s Headline), and azoxystrobin (Syngenta’s Quadris).

EPA also approved quarantine emergency exemptions (Section 18s) for several other products on the condition that the manufacturers submit those fungicides for Section 3 approval.

Martin Draper — national program leader, plant pathology for USDA’s Cooperative State Research, Education, and Extension Service — discussed the progress of the Section 18 fungicides at the recent 2006 National Soybean Rust Symposium, combining EPA and industry projections for registration dates (see chart).

According to Draper, EPA anticipates taking action on all Section 3 submissions by this year’s growing season.

However, there’s a new concern about these fungicides as they transition from Section 18 to Section 3 status, says Draper. Many retailers and growers have these products — with Section 18 labels — in storage, and the Section 3 label may not match.

There are some resulting issues, he says, that will need to be addressed, including: Will there be supplemental labels to bridge the difference and what are the regulatory/enforcement implications?

For more information on the progress of the Section 18 soybean rust fungicides, visit www.epa.gov/oppfead1/cb/csb_page/updates/soybean_rust.htm.

Leaf Damage A Factor, Too

Damage the soybean leaf, damage the plant’s yield. This is a vital piece of information that Saratha Kumudini and her international research team didn’t have in hand when they first set out to develop a yield loss prediction model for Asian soybean rust.

Kumudini, a University of Kentucky crop physiologist, and her team already knew that defoliation and growth stage were factors in yield loss. What they’ve now determined is that damaged leaves can greatly impact the soybean plant’s ability to absorb radiant energy, causing reduced yields.

More research will be conducted this year. The team hopes to have a yield-loss prediction model ready for use within two to three years. For details, visit www.rustready.com.

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