The Colorado River Basin is managed in a complex and multi-level legal structure that involves many stakeholders. The Colorado River watershed is divided into the Upper and Lower Basins. The Upper Basin includes the states of Wyoming, Colorado, Utah and New Mexico. The Lower Basin includes Arizona, California and Nevada. A binational treaty governs the releases to Mexico from the Colorado River.
Within the overall structure of the Law of the River, the basin states and the Boulder Canyon Project Act water contractors must work collectively to address their water supply issues. In the Lower Basin, water supplies are administered by a federal water master, designated by the Secretary of the Interior working through the Bureau of Reclamation. In the Upper Basin, the Upper Colorado River Commission serves in the role of administering compliance with the 1922 Colorado River Compact. In addition, every basin also has its own unique set of law governing rights that apply within those states.
The 2007 Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for both Lake Powell and Lake Mead are set to expire in 2026. The seven Colorado River Basin states and stakeholders must work together to develop the new criteria that will replace those guidelines. At present, there is a gridlock in those negotiations between the Upper and Lower Basin states and it must be resolved in 2025 to replace those guidelines expiring in 2026.
As part of the 2025 SW Ag Summit program on Thursday, 20 February on the campus of Arizona Western College, two sessions will be held addressing the future of the Colorado River and management plans for water allocations that will be very important for agriculture in the lower Colorado River Valley in the next decade. This will include a keynote session in the morning and a breakout session will follow. The schedule for these two sessions is listed below.
Keynote Program, 7:30 a.m., 20 February 2025, College Community Center (3C)
The Future of the Colorado River
Breakout Session – Colorado River Update, 9:30 a.m. MAC 106
Outlook on Basin wide Negotiations for the 2026 Operational Guidelines
I hope you are frolicking in the fields of wildflowers picking the prettiest bugs.
I was scheduled to interview for plant pathologist position at Yuma on October 18, 2019. Few weeks before that date, I emailed Dr. Palumbo asking about the agriculture system in Yuma and what will be expected of me. He sent me every information that one can think of, which at the time I thought oh how nice!
When I started the position here and saw how much he does and how much busy he stays, I was eternally grateful of the time he took to provide me all the information, especially to someone he did not know at all.
Fast forward to first month at my job someone told me that the community wants me to be the Palumbo of Plant Pathology and I remember thinking what a big thing to ask..
He was my next-door mentor, and I would stop by with questions all the time especially after passing of my predecessor Dr. Matheron. Dr. Palumbo was always there to answer any question, gave me that little boost I needed, a little courage to write that email I needed to write, a rigid answer to stand my ground if needed. And not to mention the plant diagnosis. When the submitted samples did not look like a pathogen, taking samples to his office where he would look for insects with his little handheld lenses was one of my favorite times.
I also got to work with him in couple of projects, and he would tell me “call me John”. Uhh no, that was never going to happen.. until my last interaction with him, I would fluster when I talked to him, I would get nervous to have one of my idols listening to ME? Most times, I would forget what I was going to ask but at the same time be incredibly flabbergasted by the fact that I get to work next to this legend of a man, and get his opinions about pest management. Though I really did not like giving talks after him, as honestly, I would have nothing to offer after he has talked. Every time he waved at me in a meeting, I would blush and keep smiling for minutes, and I always knew I will forever be a fangirl..
Until we meet again.
Last week, we initiated our first on-farm demonstration of soil steaming of the season with our self-propelled steam applicator. The machine is designed to inject steam into the soil and raise soil temperatures to levels sufficient to kill weed seed and soilborne pathogens (140°F for > 20 minutes). After the soil cools (< ½ day), the crop is planted into the disinfested soil.
In this trial, we are examining the viability of soil steaming for controlling weeds in organic carrot at the field scale level (plot size > ½ ac). The machine performed well in that it was able to reach target soil temperatures at reasonable travel speeds (> 0.4 mph), provide uniform temperature distribution across the bed and form nicely shaped beds suitable for subsequent planting. Stay tuned for reports of weed control efficacy, crop yield and overall profitability as compared to the grower standard.
We are seeking collaborators to conduct similar field-scale trials/demos in Yuma, AZ. The primary objectives are to assess the viability of soil steaming at the field-scale level and obtain grower feedback on the device’s commercial potential. The machine can be adjusted to work with most bed configurations including narrow (40”, 42”) and wide (80”, 84”) beds, and is suitable for use in conventional or organic crops (soil steaming is organically compliant). To date, the device has been successfully trialed in iceberg lettuce, romaine lettuce, baby leaf spinach and carrot crops.
If you are interested in an on-farm demo of soil steaming, please let me know. I’d be happy to work with you.
Fig. 1. On-farm demonstration of a self-propelled steam applicator for weed and
disease control
Acknowledgements
This project is sponsored and funded in part by the Arizona Specialty Crop Block Grant Program and the Propane Education and Research Council (PERC). We greatly appreciate their support.
In a letter from the EPA to AMVAC dated May 2, 2024 that you can find by clicking here: https://www.regulations.gov/document/EPA-HQ-OPP-2011-0374-0116 EPA "thanks AMVAC for voluntarily proposing to discontinue DCPA use on onions".
If DCPA is not available next season our options for onion weed control are reduced. Please read the work from Carl Bell https://escholarship.org/content/qt91w4d06x/qt91w4d06x.pdf?t=lnryxp&v=lg regarding combining bensulide and pendimethalin for weeds control in onions. He did this research due to a similar situation with Dacthal in 1996.
We tested last season 2 qts of Prefar and 0.5 pt of Prowl and the weed control looked promising. There appears to be a synergystic effect between these products. Some phytotoxicity was observed and stand was affected. Bell reported (2001) that "a reduced crop stand does not always equal a reduced yield, since onions compensate to some extent by producing larger bulbs".
Some PCAs are planning IPM strategies and are suggesting for green onions: "Apply Goal early post emergence with clethodim if you have grasses then Prowl at layby".
What do you think? keep sending your comments to the Veg IPM Team and let us know what you think.
Included below is a list of organic insecticides that you can consider for your organic IPM programs. Although there are few alternative organic insecticide options, it is important to rotate when possible. Like conventional insecticides, continuous exposure to the same biopesticides may pose some risk of further reducing their efficacy and leading to the development of resistance.
A good organic insecticide rotation practice is to alternate selective organic insecticides with broad-spectrum organic insecticides. The use of selective organic insecticides favors the increase of beneficial arthropod populations which may help to keep the pest population in check and delay repeated application of insecticides. When the population of lepidopteran pests is low, spraying Bt-based insecticides first and pyrethrin or Spinosad-based products thereafter is a good strategy. Proper insecticide rotation is important because it can help reduce insecticide application frequency, resulting in reduced crop production costs.
Tank-mixing can help improve the efficacy of some organic insecticides against some target pests. Tank-mixing a Bt insecticide with pyrethrin, such as Xentari + Pyganic or Dipel + Pyganic, can be an effective combination for controlling lepidopteran larvae. Additionally, combining Pyganic and a neem-based insecticide like Aza-Direct can be a favorable combination for small lepidopteran larvae. Tank-mixing Entrust (spinosad) and M-Pede can help suppress flea beetles and bagrada bugs.
Lake Mead, the nation’s largest reservoir, continues to decline to historic lows, posing a critical hydrological challenge in the Southwest with significant implications for Arizona agriculture. Prolonged and severe drought across the Colorado River Basin has led to cascading water-use reductions, including a Tier 1 shortage that has cut central Arizona’s agricultural water allocations by 65%.
The drought situation in Arizona has intensified significantly since late 2024 (see Figures 1 & 2 to determine the differences in extreme drought expansion), with extreme drought (D3) conditions spreading across much of the state. Yuma, La Paz, Maricopa, Gila, and now Greenlee counties are fully engulfed in D3 drought, while the expansion has also reached parts of Pima, Mohave, Yavapai, Navajo, Apache, Santa Cruz, Graham, and Cochise counties. This alarming trend signals a severe water deficit, raising serious concerns about its impact on agriculture, water resources, ecosystems, and communities statewide. This crisis underscores the urgent need for innovative strategies to sustain agriculture and secure water resources in the region.
One approach to addressing this crisis is implementing conservative water management, which includes adopting advanced soil moisture monitoring technologies. This raises an important question: How do you select the right soil moisture sensors for irrigation management decisions?
A wide range of soil moisture sensors are commercially available for agricultural use. However, selecting the most suitable sensor for Yuma’s arid environment, where soils are characterized by a pH greater than 8 requires careful consideration of key criteria. The selection process should focus on two critical aspects:
(a) Operational Feasibility:
(b) Performance Accuracy:
Calibration: Consideration of factory calibrations versus site-specific calibrations for improved measurement precision.
