A six-year evaluation of the cumulative impacts of glyphosate impacts on orchard crops

By O. Adewale Osipitan

Reposted from the UC Weed Science Blog

Glyphosate is one of the most commonly used herbicides in orchard crops in California both in terms of treated acres and amount of active ingredient applied. Weed managers are generally familiar with the attributes of glyphosate as a postemergence herbicide. Duke and Powles (2008) published an article in Pest Management Science entitled “Glyphosate: a once-in-a-century-herbicide”. Suffice to say, it's a pretty useful herbicide, if that's your thing. It has also been the subject of several controversies in the past couple of decades.

One of those controversies was a source of frequent extension questions from California farmers and Pest Control Advisors about 10 years ago. In the late 2000's there were several researcher articles from work done in glyphosate-tolerant soybeans that suggested there might be some nontarget impacts of glyphosate on crop nutrient status, plant disease interaction, and microbial community effects. In California tree crops concern generally focused around whether glyphosate in the soil could chelate micronutrients and lead to nutrient deficiencies and/or if repeated use could cause enough glyphosate to accumulate in soil and have direct impacts on the trees.

Read the rest at the UC Weed Science Blog.