The public's increasing demand for safe “green” products has resulted in many new environmentally-friendly products becoming available for controlling weeds in the garden and landscape. Even though information for home gardeners on the efficacy of these new products is limited, their use is still heavily promoted by environmental awareness groups and public agencies in an effort to reduce the use of other herbicides that have a greater potential to contaminate surface waters. Retailers are beginning to dedicate shelf space to pesticides that are considered least-toxic alternatives; most of them containing essential oils or other natural plant extracts targeting weeds.

The majority of these “green”...

One of my major areas of research the past few years has been related to alternatives to methyl bromide fumigation in perennial crop nurseries.  A list of recent posts on soil fumigation research and issues is available.  Some specific research areas have included reducing atmospheric emissions of methyl bromide alternatives and on alternative fumigants such as methyl iodide. 



Today, I thought I'd share some basic information on the nursery cropping system as well as two recent...

      As we start the winter season today, many locals and tourist to our area look forward to the end of winter when the Napa Valley comes alive with the beauty of yellow mustard flower that has been celebrated for many years in the ‘Napa Valley Mustard Festival.’ No one can argue the aesthetic beauty of a hillside vineyard covered in the yellow flower of mustard. Working as the Farm Advisor who oversees vineyard floor management in the Napa Valley, I am at times troubled by the sight. Is there an invasive weed that has ‘taken over’ the vineyards? If it is a covercrop, is it good cover crop? And the question I get most often from grower and city folk alike, ‘What kind of mustard is that?’ Consulting the ‘Weeds of...

Herbicide resistance is the inability of an herbicide to control a weed species that it was previously effective against. Weed scientists will often tell growers that a means for managing resistance is to rotate herbicide chemistries such that you are rotating among mechanisms of action. Sometimes (and I am guilty of this, too) we neglect to describe what a mechanism of action actually is…and why it is so darn important to us. So, back to the basics.

What is an herbicide? An herbicide is defined as a chemical substance that is used to eliminate unwanted plants. This is a very general description and it is important to remember that herbicides differ with respect to their use (for example, pre-emergence or...