63^rd Annual Conference
California Weed Science Society
Weed Control: Balancing Biology, Reality & Sustainability

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...

Last week (December 1, 2010), the California Department of Pesticide Regulation (CDPR) registered the soil fumigant Midas for use in the state following months (years) of controversy and protests. I’ve been meaning to talk a bit about soil fumigation in this blog and I’ll try to address the general issues in a future post. For today, I’ll focus on methyl iodide since it is a "hot topic".

Midas, marketed in the US by Arysta LifeScience, is a combination of methyl iodide...

Early winter is is a good time of year to talk about another landscape weed problem - catchweed bedstraw (Galium aperine) also known as cleavers in much of the rest of the world (among many other names). 



In California, bedstraw is summer or winter annual and we are starting to see the beginning of the winter germination flush in the Davis area.  We usually see a lot of bedstraw germiantion in the early winter after the rain starts and the soils start to cool; however, there is often a secondary flush of germination in the late winter and earlys spring (Feb-March).  Bedstraw will grow into the summer but really doesn't do very well in the hottest times of the year.  It tends to complete its lifecycle by...