Watergrass

We are having more and more difficulties controlling watergrass over the past 20 or so years. We know that as of the early 2000s, we had found multiple-herbicide resistant late watergrass (also known as mimic), as well as multiple-herbicide resistant barnyardgrass. For early watergrass, we now have resistant biotypes (to thiobencarb), with none recorded as being multiple-herbicide resistant.

In 2017, two rice fields were identified with an unknown watergrass biotype (or species) that looked very different than the three main known species that infest California rice fields (late watergrass, early watergrass, and barnyardgrass). Both fields had...

Richard Smith is the UC Cooperative Extension Vegetable Crop Production and Weed Science Farm Advisor in Monterey, Santa Cruz and San Benito counties.

Automated weeders remove weeds inside the three- to five-inch-wide uncultivated band left around the seedline by standard cultivation. Automated weeder technology has improved significantly over the past decade. All automated weeders use 1) cameras to detect plants, 2) a computer to process the image and make decisions about which plants to keep and which to remove and 3) a kill mechanism. Kill mechanism that operates in the seedline used by currently available machines are either a split blade that opens around keeper...

From the Western Farm Press • March 17, 2021

By Lee Allen

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Recurring, multiple-resistance species are among the biggest challenges.

Brad Hanson gets down...