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
Frost and freeze damage affect countless fruit and vegetable growers leading to yield losses and occasionally the loss of the entire crop. Frost damage occurs when the temperature briefly dips below freezing (32°F).With a frost, the water within plant tissue may or may not actually freeze, depending on other conditions. A frost becomes a freeze event when ice forms within and between the cell walls of plant tissue. When this occurs, water expands and can burst cell walls. Symptoms of frost damage on vegetables include brown or blackening of plant tissues, dropping of leaves and flowers, translucent limp leaves, and cracking of the fruit. Symptoms are usually vegetable specific and vary depending on the hardiness of the crop and lowest temperature reached. A lot of times frost injury is followed by secondary infection by bacteria or opportunist fungi confusing with plant disease.
Most susceptible to frost and freezing injury: Asparagus, snap beans, Cucumbers, eggplant, lemons, lettuce, limes, okra, peppers, sweet potato
Moderately susceptible to frost and freezing injury: Broccoli, Carrots, Cauliflower, Celery, Grapefruit, Grapes, Oranges, Parsley, Radish, Spinach, Squash
Least susceptible to frost and freezing injury: Brussels sprouts, Cabbage, Dates, Kale, Kohlrabi, Parsnips, Turnips, Beets
More information:
References
Jay-Russell, M.T. (2013). What is the risk from wild animalsin food-borne pathogen contamination of plants?. CABI Reviews 4(8),1-16.https://doi: 10.1079/PAVSNNR20138040
Fig. 1. Bird fecal matter on romaine lettuce.
Fig. 2. Gull flying over romaine lettuce being harvested.
Fig. 3. Gulls flying over irrigation canal near lettuce field
being harvested.
Fig. 4. Bird fecal matter on lettuce harvesting equipment.
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.
Results of pheromone and sticky trap catches can be viewed here.
Corn earworm: CEW moth counts remain at low levels in all areas, well below average for this time of year.
Beet armyworm: Trap increased areawide; above average compared to previous years.
Cabbage looper: Cabbage looper counts decreased in all areas; below average for this time of season.
Diamondback moth: DBM moth counts decreased in most areas. About average for this time of the year.
Whitefly: Adult movement beginning at low levels, average for early spring.
Thrips: Thrips adult counts reached their peak for the season. Above average compared with previous years.
Aphids: Aphid movement decreased in all areas; below average for late-March.
Leafminers: Adults remain low in most locations, below average for March.
