We commonly select for specific weeds in agricultural systems because of the neccessary managment practices.  Cultivation, fertilization, irrigation, weed management, etc all can affect the weeds in a given field.  Some weeds prosper under high fertility, high disturbance, and regular irrigation and tend to be very common in ag fields.  Other species do not do as well in those conditions and are found in roadsides, field margins, or non crop areas.

Similar issues can occur with our selection of ornamental plants.  Some plants are values as ornamental plants becasue they are very adaptable and easy to grow, can escape cultivation and become weedy in various ecosystems.  Here is a link to an article in a magazine called High...

I only have a moment to post today but wanted to put up two links concerning the research and publications of a retired Purdue University researcher.  Dr. Don Huber has made a number of claims about the effects of glyphosate-resistant cropping systems on soil pathogen populations and micronutrient uptake.  I have received several calls about this (particularly the micronutrient aspect) in recent months.

The first link is to a Washington Post article entitled "Researcher's warning about genetically modified crops spreads, but scientists question...

Today I wanted to follow up on my post from a few weeks ago about volatile organic compounds (VOC) from herbicides and other non-fumigant pesticides. In case you missed it, the discussion on February 27 was about an online VOC calculator developed by California Department of Pesticide Regulation (CDPR). This tool allows users to compare calculated VOC emissions of individual pesticides or season-long pesticide programs.

Earlier this month, I attended the 2011 Plant and Soil Conference which was held in Fresno this year.  This annual meeting put on by the California Chapter of the American Society of Agronomy (http://calasa.ucdavis.edu/ ) usually has several sessions during the two-day program designed to update Certified Crop Advisors, Pest Control Advisors, and other professional agronomists on current research and regulatory issues.  One of the speakers in the Environmental Quality Session, Pam Wofford from CDPR, spoke about reducing emissions of Volatile Organic Compounds (VOC) from pesticides by switching formulations.  I thought I’d touch on that issue today.

There are a number of definitions of...

This week I received an email request for information on the soil concentration of herbicide necessary to have a phytotoxic effect.  This is a simple-sounding question and I was able to confidently say “Well, that depends….”. 

Of course this isn’t a simple question at all because of the great differences among herbicides, soil types, environments, and in plant susceptibility not to mention complicated interactions among the factors.  As an example, in the herbicide treatment table IPM guidelines for Pear (http://www.ipm.ucdavis.edu/PMG/r603700311.html) it is obvious that herbicides can be active at quite different concentrations.  In this table, there is up to a...