There are at least 10 ways adjuvants can make your post-emergence herbicide work harder — and literally hundreds of adjuvant products to choose from. Here’s a look at what’s causing this proliferation and how you can be sure you’re treating your crops right.

1. Why are there 
so many adjuvants?

Post-emergence herbicide effectiveness depends on help from adjuvants to assure spray droplet retention and herbicide absorption by weed foliage. The fast-growing adjuvant stable is the result of increased market focus on post-emergence herbicides, competitive pressure to offer more user-friendly adjuvants and, in a few cases, the research and development of novel new products, says Bryan Young, a weed specialist at Southern Illinois University (SIU).

There’s no question the adjuvant market is crowded and confusing. Young’s 8th edition of the Compendium of Herbicide Adjuvants, released in January 2006, contains 523 products from 39 companies. In 1992, the first compendium contained only 72 adjuvants from 22 companies. Proof of performance is not legally required to bring an adjuvant to market because the products are not regulated by the EPA.

Combining Functions. Many of the newer adjuvants are combinations of proven ingredients. “Realistically, if you take away the sizzle and the sell, there is little new chemistry in the adjuvant market,” says Kent Woodall, marketing manger for Rosens, a multi-state ag chem distributor with several proprietary adjuvant products, including Array.

“It’s a lot like the herbicide market. Lumax herbicide, for example, is a popular new formulation,” Woodall notes. “But if you look at…