Western agricultural concerns about weed cost increases center on the growing problem of herbicide resistance.

At the recent California Weed Science Society annual meeting in Santa Barbara, Calif., in the traditional* realm of weed control, Brad Hanson, UCCE weed science specialist, addressed the issue of off-site movement of herbicides, a growing concern because of heightened regulations to prevent ground and surface water contamination.

 “Any herbicide that misses the target or moves from a plant treatment zone is off-target,” said Hanson.

Herbicides tend to be more persistent once leached below root zone, noted Hanson. To avoid off target movement, Hanson encouraged proper applicator training and equipment...

Abstract: Agricultural weed management has become entrenched in a single tactic—herbicide—resistant crops—and needs greater emphasis on integrated practices that are sustainable over the long term. In response to the outbreak of glyphosate-resistant weeds, the seed and agrichemical industries are developing crops that are genetically modified to have combined resistance to glyphosate and synthetic auxin herbicides. This technology will allow these herbicides to be used over vastly expanded areas and will likely create three interrelated challenges for sustainable weed management. First, crops with stacked herbicide resistance are likely to increase the severity of resistant weeds. Second, these crops will facilitate a...

Abstract: Solar tents, which are safe, inexpensive, and easy to construct, can be used to inactivate unwanted weed plant propagative materials, onsite. During two field trials in the San Joaquin Valley of California, from Sept 2 to 7, 2010, solar tents produced diurnal temperature maxima within closed sample bags of 63.5–76.7°C. The mean maximum temperatures within the sample bags were 32.9–42.1°C higher than those of ambient air, and temperatures greater-than or equal to 60°C were maintained for 3.2–6.0 h each afternoon during the field trials. Rhizome segments, excavated and excised from a local infestation of the important weed pest Sorghum halepense (johnsongrass), were used to evaluate effects of...

I’ve noticed a slow and increasing trend lately, the level of communication about weeds has been on the decline. Now I have very little data outside of Southern California to back up my assertion, so I look to you to provide a sense of optimism. Your comments to counter my observations are greatly appreciated.

Several state and federal agencies along with local governments and organizations have been, one by one, missing weed management meetings or local workshops and symposia. Now this is not something entirely new or unpredicted, attending an invasive plant management group is certainly not as fun as being in the field for the day. It is important work: organizing regional projects, deciding which grants to write,...