The 2016 Compendium of Herbicide Adjuvants is available from Purdue Extension through Purdue's The Education Store.

Now in its 13th edition, the publication lists 779 products from 38 companies. Each listing contains the product name, principal functioning agents, use rates, special comments and name of the manufacturer or distributor. The first edition, published in 1992, contained 76 listings from 22 companies.

An adjuvant is any substance added to an herbicide to increase its effectiveness or make it easier to apply. A combination of factors account for the popularity of herbicide adjuvants over the past several decades, said Bryan Young, professor of weed science and editor of the publication.

"Foliar herbicide applications continue to be a critical part of weed management and growers must optimize herbicide efficacy to minimize the risk of herbicide failure that favors the selection of herbicide-resistant weeds," he said. "In addition, significant advancements and innovations in herbicide adjuvant chemistry have evolved that allow for the combination of multiple adjuvant chemistries into a single multi-functional product.”

The purpose of the Compendium is to provide a format that allows for a comparison of adjuvant products that fall within or across the different adjuvant categories, Young said.

"Ultimately, greater knowledge of herbicide adjuvants will lead to more confidence in product selection and the value these adjuvants provide to facilitate effective herbicide applications," he said.

Young's co-authors are Joseph Matthews, assistant scientist in plant soil and agricultural systems at Southern Illinois University Carbondale, and Fred Whitford, head of the Purdue Pesticide Programs.

Print versions of the compendium are available for $5.50 per copy. Free downloads are also available from The Education Store. For more information or to order, go to https://edustore.purdue.edu/item.asp?Item_Number=PPP-115