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United States Department of Agriculture

Agricultural Research Service

Martin Williams



Weeds cost the U.S. some $31 billion in lost crop production annually, despite $8 billion spent on herbicides. Several weed-related issues exist, including weed biotypes resistant to nearly every herbicide mode of action, over-reliance on a dwindling number of herbicides, and lack of herbicide R&D, particularly concerning new modes of action. Special issues in vegetable and minor crops include high susceptibility to losses in yield and quality, limited weed control options, labor scarcity, and high expense of handweeding.


Climate change is expected to exacerbate many weed problems. Plasticity and genetic diversity in weed populations allow them to rapidly adapt to changing conditions. Latest research predicts reduced control, increased weed fitness, and range expansion in future climate scenarios. As weeds shift in response to current management practices and climate change, so must weed management track this moving target. Research and development of weed management systems prepared for greater environmental variability are thus essential to food security and natural resource preservation.


Research Interests

The goal of my lab is to develop weed management systems that are economically viable and environmentally sound. To that end, my lab studies several facets of weed/crop ecology and management. We examine the potential of a full scope of weed/crop management tactics, including chemical and non-chemical, and give particular study to the integration of cultural practices with judicious use of herbicides. I have broad interests in different crops and cropping systems, though often find issues in under-studied systems most intriguing.


Currently my efforts are focused on the following topics:


1. Interactions between crops and plant stressors including weeds, pathogens, and environmental variability.

2. Opportunities to bolster crop competitiveness with weeds, including the interactive effects of

a. crop phenotypic diversity
b. cultural practices
c. physical methods
3. Issues in commercial vegetable cropping systems, including implications of biomass feedstock production.
4. Special issues related to herbicide use in minor crops.



Last Modified: 9/29/2013