As part of the Southwest Ag Summit (SWAS) that took place in Yuma in late February, we conducted a breakout session on Thursday, 22 February 2024 titled “Colorado River Water Shortage: Agricultural Perspectives”.
This session provided a brief review of the background, the current situation on the Colorado River, and very importantly it included an outlook on the current discussions among the basin states to negotiate a new compromise for the guidelines of use under conditions of water shortage. These new guidelines will go into place at the end of 2026. Both the upper and lower basin states have now submitted draft proposals to the Bureau of Reclamation (BoR) on 6 March 2024.
This breakout session at the Southwest Ag Summit provided up to date information and first-hand insight into the process. The participants were each uniquely qualified to offer valuable perspectives on these issues.
The participants included Elston Grubaugh, Wellton-Mohawk Irrigation and Drainage District, who introduced the discussion and served as program moderator. Bart Fisher, Palo Verder Irrigation District and State of California Colorado River Water Board member, Fisher Ranch, Blythe CA, provided a California perspective with a background of extensive experience in Colorado River management over several decades. Hank Auza, Yuma County Water User’s Association President and Yuma Ag Water Coalition representative, Barkley Co. of Arizona, Yuma AZ, provided an Arizona perspective.
Elston has extensive experience working in irrigation districts on both the California and Arizona sides of the Colorado River. He has a valuable perspective, and he plays an important role in the management of Colorado River water in the Yuma area. We are fortunate to have Elston provide his direction for this program and offer his point of view.
Both Bart and Hank are directly involved in the ongoing reconsultation negotiations directed at developing the new Colorado River management guidelines that will go into place in 2026. Both are part of their state's delegation in the current negotiations and represent the lower basin. Bart and Hank are not only responsible for representing California and Arizona, but they are both active farmers in the Palo Verde Valley and Yuma area valleys, and they bring valuable perspectives to the discussions.
The goal of negotiations among the seven U.S. Colorado River basin states has been to submit a single document proposing guidelines to the BoR. However, as was discussed at this program at the SWAS, the upper and lower basin state groups have been dealing with significant differences and were not able to come to a consensus agreement. As a result, the upper and lower basin delegations each submitted separate proposals to the BoR in early March.
There is still a chance that both the upper and lower basin state groups can reach a common agreement for a unified proposal. In the meantime, both proposals are under review by the BoR. Officials with the BoR have indicated that they will be working with the basin states in the next six months to develop a consensus draft proposal for post-2026 river management by the end of 2024.
Further details on the two proposals submitted on 6 March 2024 by the upper and lower basin groups and contrasting the two will be forthcoming in a future article.
For the excellent program that was provided at the 2024 SWAS, I want to thank Elston, Bart, and Hank for their outstanding presentations. Each of the participants in this program brought a wealth of knowledge and experience to the discussion.
Specifically for Bart and Hank, we are all indebted to them for their contributions and hard work while serving on the lower basin state delegations during these critical and challenging negotiations. Their firsthand perspectives and contributions to this program are very much appreciated.
It’s unfortunately a very great season to be a plant pathologist…
We have confirmed the first sample of Fusarium wilt on lettuce submitted to the Yuma Plant Health Clinic from Yuma County. The stunted seedlings looked like any other typical case of damping-off at the seedling stage. When plated on culture media, subsequently confirmed Fusarium colonies grew abundantly from the declining plant tissues. If you’re not already on guard and scouting, this is a warning that Fusarium is active in Yuma County.
Adding on to this early alert, we’ve received a surge of submissions of young brassicas to the clinic. Several severely wilted and declining plants from around Yuma County have cultured positive for Pythium, likely as an opportunistic invader coming in on the back of all the early-season rain that brought stress to seeds and young transplants. Growers may want to consider oomycides, but only if the seedling disease is first confirmed to be Pythium. Remember, many seedling diseases caused by true fungi are indistinguishable from those caused by Pythium.
If you have any concerns regarding the health of your plants/crops please consider submitting samples to the Yuma Plant Health Clinic for diagnostic service or booking a field visit with me:
Chris Detranaltes
Cooperative Extension – Yuma County
Email: cdetranaltes@arizona.edu
Cell: 602-689-7328
6425 W 8th St Yuma, Arizona 85364 – Room 109
Presentation given at 2021 ASABE Annual International Meeting on the development and evaluation of a novel, band steam applicator for controlling soilborne pathogens and weeds in lettuce. Band-steam is where steam is used to heat narrow strips of soil to levels sufficient to kill soilborne pathogens and weeds (140 °F for 20 minutes). Development of a band-steam applicator that applies steam in 4" wide by 2" deep band centered on the seedline is presented. Two trials investigating the use of band-steam for controlling Sclerotinia lettuce drop and weeds in lettuce were conducted. Trial results were promising. Highlights included finding that treatment with steam provided better than 85% weed control, and the unexpected result that crop yields were improved by more than 24%. Energy requirements were high and treatment costs were more than $650/acre. Band-steam may be a viable technique for controlling soilborne pests in high value vegetable crops such as lettuce if the significant yield increases found in this study can be realized.
To watch presentation click: A Novel Band-Steam Applicator
Devrinol (napropamide), herbicide has been used in cole crop production at preemergence for control of many annual grasses and some broadleaf weeds. With the revision of Dacthal (DCPA) some of our PCAs are turning their attention to this tool for weed control. Like many other preemergence herbicides, it works by inhibiting root growth after weed seeds have germinated. It has sometimes injured lettuce when too much was concentrated near the lettuce seed.
Napropamide is a selective systemic herbicide that according to the label limits the growth of grasses in our area such as Barnyard grass, Junglerice, Wild barley, Annual bluegrass, Canarygrass, Foxtail, Goosegrass, Johnsongrass, Wildoats, Sandbur and Sprangletop.
Broadleaves that we have included in the label are: Lambaquarter, Prickly lettuce, Little Mallow, Redroot pigweed, Common and Horse purslane and Sowthistle.
The PCA study guide for Arizona states that minimum re-cropping intervals of 12 months for cotton, melons and alfalfa, 6 months wheat, 2 for lettuce and 0 for cole crops. We have seen in our trials that head lettuce showed sensitivity to Devrinol when planting too soon.
The following chart from a broccoli trial conducted in 2015 (Tickes/Peña) show the efficacy of napropamide for control of London Rocket and Lambsquarter.
This time of year, John would often highlight Lepidopteran pests in the field and remind us of the importance of rotating insecticide modes of action. With worm pressure present in local crops, it’s a good time to revisit resistance management practices and ensure we’re protecting the effectiveness of these tools for seasons to come. For detailed guidelines, see Insecticide Resistance Management for Beet Armyworm, Cabbage Looper, and Diamondback Moth in Desert Produce Crops .
VegIPM Update Vol. 16, Num. 20
Oct. 1, 2025
Results of pheromone and sticky trap catches below!!
Corn earworm: CEW moth counts declined across all traps from last collection; average for this time of year.
Beet armyworm: BAW moth increased over the last two weeks; below average for this early produce season.
Cabbage looper: Cabbage looper counts increased in the last two collections; below average for mid-late September.
Diamondback moth: a few DBM moths were caught in the traps; consistent with previous years.
Whitefly: Adult movement decreased in most locations over the last two weeks, about average for this time of year.
Thrips: Thrips adult activity increased over the last two collections, typical for late September.
Aphids: Aphid movement absent so far; anticipate activity to pick up when winds begin blowing from N-NW.
Leafminers: Adult activity increased over the last two weeks, about average for this time of year.
