ABSTRACT
Integrated weed management (IWM) is an approach to weed control that includes a variety of agronomic practices. It has long been recommended as a means to reduce reliance on herbicides, reduce crop losses from weeds, and protect the environment (Swanton and Murphy, 1996). Liebman and Gallandt’s seminal work Many Little Hammers: Ecological Management of Crop-Weed Interactions (1997) was for many, including us, an agroecological call to arms. In it, they used a metaphor to explain that in order to control weeds effectively, we cannot rely solely on one big hammer (herbicides) but instead must use many little hammers (several different nonherbicidal methods in addition to herbicides). They, and many researchers after them, provided extensive lists of cultural, physical, and biological control methods that farmers should adopt when practicing IWM (e.g., Buhler, 2002). Nevertheless, relatively few farmers seem to have implemented IWM (Llewellyn, 2007). We believe that farmers reject IWM because they perceive it to be an overly complex approach. What is needed is an assessment of different nonherbicidal weed control methods to determine their relative effects and their potential as part of an IWM approach. To use Liebman and Gallandt’s analogy, we need to determine which hammers are big and likely to work predictably, which hammers are small and won’t always work, which hammers hit the mark when used together, and which hammers will only hit your thumb and are best left in the toolbox.
