American Vanguard Enters into Exclusive Long-Term Licensing Agreement for New Post-Harvest Potato Sprout Inhibitor.

NEWPORT BEACH, Calif. -- American Vanguard Corporation (AMEX: AVD), today announced that its subsidiary, AMVAC Chemical Corporation, entered into an exclusive, long-term licensing agreement with Washington State University Research Foundation (WSURF) that will enable the Company to develop, register and commercialize a highly effective potato sprout inhibitor for post-harvest use in the US and Canada. Terms of the agreement were not disclosed.

Traditional post-harvest potato sprout inhibitors such as chlorpropham (CIPC) are being used on over 5 million tons of all US fresh market and processing potatoes ensuring the availability of potatoes to consumers year-round. Under the terms of the agreement, AMVAC will obtain license rights for the life of patents covering a wide range of compounds that have been shown to provide excellent sprout inhibition. The new class of inhibitors will be developed as more environmentally-friendly alternatives to existing products for the purpose of producing higher quality potatoes of all types and longer shelf life. Additionally, since these inhibitors are based on naturally-occurring plant compounds, they may be approved for use on organic potatoes.

The key patent for the potato sprout inhibitors was issued in the US in February 2005, and a similar patent is pending in Canada. AMVAC plans to immediately begin the registration process for the primary compound as well as generate efficacy data, and expects to submit a complete registration dossier in the next 15-18 months in both the US and Canada. AMVAC would hope to launch products during the later part of the 2008 season.

Eric Wintemute, President and CEO of American Vanguard, stated, "We are extremely pleased to license this breakthrough technology. Testing at Washington State University has indicated that for sprout inhibition, this technology will be both efficacious and provide a new, softer alternative to growers and processors. This agreement represents our second license of newly patented technology. The sprout inhibitor complements our three pre-harvest potato products; Vapam(R), K-Pam(TM), and Blocker(TM), and should provide a unique and flexible product to the potato grower for post-harvest use. We are pleased to partner with WSURF on this exciting opportunity, which we believe will expand post-harvest management options for sprout inhibition in both processing and fresh-market potatoes."

Dr. Keith Jones, Executive Director at Washington State University Research Foundation, added, "We believe our research has the potential to have major impact on the way potato growers of Washington and beyond control potato sprouting in storage. We chose to work with AMVAC because of the company's record of success with niche product lines. We look forward to a long, mutually rewarding relationship."

About American Vanguard

American Vanguard Corporation is a diversified specialty and agricultural products company that develops and markets products for crop protection and management, turf and ornamentals management, and public and animal health. The Company's basic strategy is to acquire brand name, niche product lines from larger companies that divest mature products to focus on newly discovered molecules. During 2005, American Vanguard was recognized as one of BusinessWeek's Hot Growth Companies (#72), FORTUNE Small Business' America's 100 Fastest Growing Small Companies (#40) and Forbes' 200 Best Small Companies (#59). 2005 marks the third consecutive year American Vanguard has been included on these three lists - the only company to hold this honor. American Vanguard is included on the Russell 2000(R) and Russell(R) 3000 Indexes. To learn more about American Vanguard, please reference the Company's web site at www.american-vanguard.com.

The Company, from time to time, may discuss forward-looking information. Except for the historical information contained in this release, all forward-looking statements are estimates by the Company's management and are subject to various risks and uncertainties that may cause results to differ from management's current expectations. Such factors include weather conditions, changes in regulatory policy and other risks as detailed from time-to-time in the Company's SEC reports and filings. All forward-looking statements, if any, in this release represent the Company's judgment as of the date of this release.