In the past several years public interest in RA has increased along with other similar designations such as sustainable agriculture, organic agriculture, etc. (Figure 1). These and similar interests tend to go in cycles, and these systems are commonly treated as new, novel, and revolutionary. There is a consistent theme and set of practices among each of these systems and they are not all new. I describe them briefly in the following sections.
Regenerative agriculture (RA) is a systems approach to crop production that emphasizes rebuilding soil health, enhancing biodiversity, and increasing the resilience of farming systems by supporting natural ecological processes. Many RA practices are grounded in old agronomic principles that predate modern conventional/chemical agriculture (CA) and remain relevant in contemporary agroecosystems (Giller, et al., 2021).
Figure 1. The frequency of key terms in books (3-year rolling averages). Source:
Google NGram Viewer, Corpus ‘English 2019’ which includes books
predominantly in the English language published in any country (Giller et al.,
2021).
Crop rotations and diversification
Crop rotation has long been recognized as a beneficial agronomic practice, and it is central to RA systems. Rotations disrupt pest and pathogen life cycles, improve nutrient cycling, and stabilize crop yields. The inclusion of legumes contributes to biologically fixed nitrogen and diverse root systems, which can reduce fertilizer requirements and benefit subsequent crops (Solberg, 1958; Troeh, et al., 1999; Tilman et al., 2002).
Organic residues and manures returned to soil
The incorporation of crop residues, green manures, compost, and animal manures replenishes soil organic matter (SOM) and soil organic carbon (SOC). As they decompose, they provide slow-release nutrients, and support soil biota. Returning organic materials enhances microbial activity, improves soil structure, and benefits soil waterholding capacity. Farmers have been utilizing these practices to sustain soil productivity for centuries (Lal, 2004).
Minimal or reduced tillage
Reduced tillage and no-till practices protect soil structure, reduce erosion, and support soil biological communities. Limiting physical disturbance promotes soil aggregation, porosity, and water infiltration, contributing to improved soil stability. Reduced tillage has long been a component of soil conservation and soil-building strategies for many years, particularly in the past 90 years since the Dust Bowl (Solberg, 1958; Troeh, et al., 1999).
Cover crops
Cover crops planted between cash crops protect soil from erosion, scavenge nutrients, add biomass, and can suppress weeds. Living roots and added organic inputs stimulate microbial activity and promote a more diverse soil microbiome. In irrigated crop production systems this practice is more challenging and expensive due to the extra water demand and special practices for a crop with no cash value. Thus, it is impractical in most cases.
Mulching and residue management
Surface residues and organic mulches help conserve soil moisture, moderate soil temperatures, and in some cases reduce weed pressure. Mulching creates a favorable microclimate for beneficial soil organisms and contributes to soil protection (Solberg, 1958; Troeh, et al., 1999). This is also a centuries-old practice (Lal, 2004) but difficult to implement in many irrigated crop systems.
Agroforestry, hedgerows, and diversified landscapes
Some regenerative systems integrate trees, shrubs, or hedgerows with crops and livestock to enhance biodiversity and nutrient cycling and potentially diversify farm income. However, these practices are not feasible in all agricultural production systems, including irrigated crop production systems in the desert Southwest (Solberg, 1958). They have been found to be more feasible in tropical and subtropical regions.
Integrated pest management (IPM) and soil biology
Regenerative agriculture emphasizes the use of natural enemies, habitat for beneficial organisms, and reduced reliance on synthetic inputs. Most of these principles align with established IPM practices that have been successfully used for decades, including in Arizona crop production systems (Stern et al., 1959; Naranjo and Ellsworth, 2009).
Nutrient cycling and long-term soil organic matter (SOM)
Building or maintaining SOM is a primary objective of RA systems. Stable SOM improves soil structure, aeration, infiltration, and water-holding capacity. Maintaining SOM has long been recognized as a critical goal in CA systems as well (Tilman et al., 2002; Lal, 2004).
Agroecosystem management
Effective management is essential to the success of any crop production system and this is true in both RA and CA systems. Successful implementation requires integrating cropping system (agroecosystem) knowledge with careful planning, monitoring of soilplant relationships, and nutrient management to maintain yield stability and long-term sustainability. Efforts to do this practically and effectively are central to the management of crop production systems in the desert Southwest. We have realized good progress over many decades, yet it is always good to review and consider where we can continue to improve.
References
Giller, R.E., H. Renske, J.A. Andersson, and J. Sumberg. 2021. Regenerative agriculture: an agronomic perspective. Outlook on Agriculture, Vol. 50(1) 13–25.
Lal, R. 2004. Soil carbon sequestration to mitigate climate change. Science. 304: 1623-1627.
Naranjo, S.E. and P.C. Ellsworth. 2009. Fifty years of the integrated control concept: moving the model and implementation forward in Arizona. Pest Manag Sci 2009; 65: 1267–1286
Solberg, E.D. 1958. Planning for stability in a great area. In: Yearbook of Agriculture, 1958. p 532-536. United States Department of Agriculture, Washington, D.C.
Stern, V.M., R.F. Smith, R. van den Bosch, and K.S. Hagen. 1959. The integrated control concept. Hilgardia 29:81-101.
Tilman, D.; Cassman, K.G.; Matson, P.A.; Naylor, R.; Polasky, S. 2002. Agricultural sustainability and intensive production practices. Nature. 418: 671-677.
Troeh, F.R., J.A. Hobbs, and R.L. Donohue. 1999. Soil and Water Conservation: Productivity and Environmental Protection. Prentice Hall.
Fall melon season is approaching, and one recurring question I've been hearing is: Will viruses be as bad this fall as they were in the spring?
The incidence and severity of melon viruses this past spring were unprecedented across Yuma County, Imperial County, and northern Mexico. This is supported by the volume of feedback we received from growers, PCAs, and industry representatives who attended the June 2nd melon virus incident response meeting. As a result, predicting what we can expect is going to happen this fall is difficult. We have no recent, if any, experience with virus pressure at this scale in spring melon to guide our expectations for the upcoming fall season. At this point, predictions are more of an educated guess without the guidance of past observations.
To quickly recap, the three main viruses that affected cucurbits this spring were cucurbit yellow stunting disorder virus (CYSDV), cucurbit chlorotic yellows virus (CCYV), and watermelon chlorotic stunt virus (WmCSV). All three are transmitted by the Biotype B whitefly (Bemisia tabaci), whose populations overwintered at unusually high levels between 2025 and 2026. Between melon seasons, these viruses persist in a wide range of crop and weed hosts, many of which show few or no visible symptoms of infection. Unfortunately, these asymptomatic plants can still serve as reservoirs, allowing both the viruses and their whitefly vectors to bridge the melon-free gap between cropping seasons and provide a source of inoculum for newly planted fields. It is an unfortunate reality that neither the whitefly vectors nor many of the alternate host plants (weeds) show symptoms or suffer ill effects while carrying these viruses. As a result, they can stealthily maintain virus populations between melon seasons and serve as a source of infection for newly planted fields.
Below is a compilation of reported host plants for CYSDV, CCYV, and WmCSV. This list reflects the viruses’ confirmed hosts identified to date but is unlikely to be exhaustive. Additional weed and crop species may also be capable of serving as reservoirs for these viruses but have yet to be discovered or reported. Note that many of these plants may grow throughout the region as weeds, native vegetation, commercial crops, or in backyard gardens:
Table 1: Primary and alternate hosts of CYSDV, CCYV, and WmCSV reported to date.
I can see this upcoming melon season unfolding in one of two ways. On one hand, the most intuitive prediction is that the high virus inoculum and abundant whitefly populations present during the spring melon season will carry over into the fall, resulting in early and significant virus pressure. On the other hand, the intensive whitefly management programs implemented throughout the spring may have suppressed vector populations to provide knockdown to pre-winter 2025 levels, resulting in lower virus incidence early in the season than at the start of spring.
Regardless of which scenario plays out, proactive and preventative management of both whiteflies and weed reservoirs remains the most effective strategy for minimizing virus pressure in fall melons. This approach targets two critical stages of the disease cycle by reducing the initial sources of virus inoculum and limiting the whitefly vectors responsible for further virus spread.
Dr. Palumbo developed a management guide for whiteflies and CYSDV in fall melons in 2024. The recommendations are based on research findings from two key publications and provide practical guidance for reducing virus risk throughout the season, from planting through netted fruit (Castle 2017a and 2017b).
Table 2: Insecticide Use Guidelines for Whitefly /CYSDV Management in Fall Melons
The earlier melons become infected with one or more of these viruses, the greater the impact on plant growth, fruit development, and ultimately yield. Even when infection cannot be completely prevented, delaying virus establishment can substantially reduce losses in both yield and fruit quality. Protecting young plants from early whitefly feeding, and virus infection, is therefore one of the most important management objectives to reducing losses.
In field trials comparing at-plant soil applications of flupyradifurone (trade name Sivanto), dinotefuran (Venom), imidacloprid (Admire Pro), and cyantraniliprole (Verimark), Dr. Palumbo and colleagues found that flupyradifurone and dinotefuran provided the greatest protection against both whiteflies and lowest final incidence of CYSDV (Castle et al. 2017b). All products were applied as a single soil shank injection at planting, allowing systemic uptake and protection during crop establishment.
Across both spring and fall trials, flupyradifurone consistently produced the lowest whitefly densities and the lowest incidence of CYSDV. Dinotefuran was the second most effective treatment, significantly reducing both whitefly populations and CYSDV incidence, although its performance was somewhat less consistent than flupyradifurone. In contrast, at-planting treatment with imidacloprid and cyantraniliprole did not consistently reduce CYSDV incidence.
Further reading:
Castle, S., Palumbo, J., Merten, P., Cowden, C. and Prabhaker, N. (2017a), Effects of foliar and systemic insecticides on whitefly transmission and incidence of cucurbit yellow stunting disorder virus. Pest. Manag. Sci., 73: 1462-1472. https://doi.org/10.1002/ps.4478
Castle, S.J., Palumbo, J.P., Merten, P. (2017b), Field evaluation of cucurbit yellow stunting disorder virus transmission by Bemisia tabaci. Virus Res., 241:220-227. doi: https://doi.org/10.1016/j.virusres.2017.03.017
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:
Christopher Detranaltes, Ph.D.
Cooperative Extension – Yuma County
Email: cdetranaltes@arizona.edu
Cell: 602-689-7328
6425 W 8th St Yuma, Arizona 85364 – Room 109
For those interested in in-row weed control, checkout the quality video below (Fig. 1) on how finger weeders (Fig. 2) are being used on a 3,600 acre organic cotton farm in Texas. The grower states that finger weeders help him achieve 95-97% weed control and are a highly cost-effective tool for lowering hand weeding costs.
Fig. 1. Carl Pepper discusses how finger weeders are used to control in-row weeds on
his 3,600 acre organic cotton farm. Click here or on image to view. (Photo credit: Tilmor
LLC, Dalton, OH)
Fig. 2. Finger weeders, an in-row weeding tool, operating in seedling cotton. Finger
weeder pairs are centered on the seed row and overlapped slightly to loosen soil in the
row and uproot small weeds.
The 2026 Yuma Southwest Ag Summit is just around the corner, and we’re excited to invite you to join us for a special session dedicated to cutting-edge weed management innovations and technology.
Field Demo: Wednesday, February 18
See the latest in precision weed control in action during our field demonstration day at the Arizona Western College, 2020 S Avenue 8E, Yuma, AZ 85365.
You will have the opportunity to watch intelligent robotic and mechanical weeding machines operate in real-world field conditions. This interactive demo is a great way to evaluate technology performance and talk directly with manufacturers and researchers about next-generation tools for vegetable production.
Session: Innovations in Weed Control and Vegetable Crop Production
Thursday, February 19 | 1:30–3:30 PM | Arizona Western College, Room AS 113 (2 AZ/CA and 2 CCA CEUs Approved)
Join us for a fast-paced lineup of talks highlighting the latest research and technologies shaping modern weed control systems:
Moderator: Dr. Mazin Saber, University of Arizona, Yuma County Cooperative Extension.
This session will offer practical insights, real data from field trials, and forward-looking discussions about robotic solutions for weed control. Whether you’re evaluating new equipment investments or looking for updates on research progress, this is a session you won’t want to miss.
We look forward to seeing you at the Southwest Ag Summit to explore how innovation continues to reshape weed management in desert vegetable systems.
The link below will take you to the complete agenda for the event.
https://acrobat.adobe.com/id/urn:aaid:sc:US:8e8d2658-6f01-41f0-9423-5f216ca6a64d
Diamondback moth (DBM), Plutella xylostella, is one of the most important insect pests of Brassica crops, including cabbage, broccoli, cauliflower, and some leafy greens. Heavy infestations can cause significant feeding damage, reduce crop quality, and increase production costs. Because DBM has a long history of developing resistance to insecticides, regular monitoring of insecticide susceptibility is essential to ensure effective management in the field. In the western United States, resistance to several key insecticide classes has been documented in field populations. For example, populations in California have shown high levels of resistance to several insecticide classes, including diamides, spinosyns, avermectins, pyrethroids, and Bacillus thuringiensis (Bt) products. More recently, outbreaks in Arizona have been associated with confirmed resistance to diamide insecticides and reports of reduced field efficacy. This highlights the importance of regular insecticide susceptibility monitoring and the implementation of resistance management strategies to maintain effective control of the pest. While field resistance and reduced efficacy reflect outcomes under production conditions, laboratory susceptibility monitoring provides a standardized approach to detect shifts in population response before or alongside observable field control issues.
To evaluate current insecticide susceptibility levels in DBM populations across Arizona's major Brassica-growing regions and some California populations, DBM larvae were collected from multiple locations in Arizona and California. DBM populations were reared in the laboratory and their progenies were tested under controlled laboratory conditions. Only one Arizona population was included in this initial assessment. Additional populations from Arizona have since been collected and are currently being tested to provide a more comprehensive understanding of insecticide susceptibility across the region.
In the laboratory, larvae were exposed to insecticides at the highest labeled field rate using a leaf-dip bioassay. The insecticides evaluated included Exirel®, Coragen®, Radiant®, Baythroid® XL, Proclaim®, IncipioTM, DiPel®, and XenTari®, representing commonly used conventional and organic management options, as well as IncipioTM, which was recently registered. These laboratory bioassays measure relative susceptibility under controlled conditions using field-collected populations reared in the laboratory. Results represent mortality at the maximum labeled rate under leaf-dip assay conditions and may not directly reflect field performance, where environmental conditions, application timing, coverage, larval stage, and population dynamics influence control. These data are intended to monitor susceptibility trends and help inform resistance management decisions. Accordingly, extrapolation to field performance should be made cautiously, recognizing both the constraints of laboratory bioassays and the mosaic of susceptibility that may exist within and among field populations.
Several Insecticides Showed High Laboratory Mortality Across Field-Collected Populations
Several of the insecticides evaluated caused high mortality of DBM larvae in laboratory assays across field populations. Proclaim, Incipio, Radiant, DiPel, and XenTari caused high mortality, indicating laboratory susceptibility across the tested populations. These products remain promising options for managing DBM in Brassica crops based on current laboratory susceptibility data.
In contrast, Coragen, Exirel, and Baythroid XL resulted in lower mortality in laboratory assays than the other insecticides (Figure 1).
Figure 1. Mean mortality (%) of DBM larvae exposed to the maximum label rate of
insecticides, combined across all six field populations from California and
Arizona.
Consistent Laboratory Mortality Across Regions, with Some Population-Level Variability
The levels of larval mortality caused by each evaluated insecticide were generally consistent across populations collected from major Brassica-growing regions, including Salinas Valley, CA; multiple sites in Coachella Valley, CA; and Gila Valley, AZ (Figure 2). Proclaim, Incipio, Radiant, DiPel, and XenTari resulted in high larval mortality under laboratory assay conditions for most DBM populations tested. However, slight reductions in larval mortality were observed in specific populations. For example, DiPel resulted in approximately 70% larval mortality in the Coachella Valley, CA population # 4, and Radiant caused approximately 55% larval mortality in the Coachella Valley, CA population #2. Despite this variability, these insecticides generally resulted in high mortality of DBM larvae across geographic locations under laboratory assay conditions (see Figure 1). In contrast, Coragen, Exirel, and Baythroid XL resulted in high larval mortality for the laboratory strain but consistently resulted in low DBM larvae mortality in the field-collected populations from Salinas Valley, CA; Coachella Valley, CA; and Gila Valley, AZ (Figure 2).
The reduced and variable levels of larval mortality observed in laboratory assays across multiple field populations for some tested insecticides highlight the importance of routine susceptibility monitoring to better understand resistance dynamics and to support informed field-level decisions regarding product selection and rotation.
Figure 2. Mortality (%) of DBM larvae from laboratory and field populations
exposed to maximum label rates of insecticides.
Key Laboratory Findings
Implications for Resistance Monitoring and Field Decision-Making
Laboratory monitoring informs our understanding of resistance trends, but field scouting remains essential to evaluate how populations respond under production conditions. As always, when in doubt, scout!
Additional Reading Materials
1. Calvin W., M. N. Keith, and B. McGrew. 2025. Guidelines for Effective Management of Diamondback Moth in Brassica Crops. University of Arizona Extension Publication. az2143. https://extension.arizona.edu/publication/guidelines-effective-management-diamondback-moth-brassica-crops
2. Calvin, W. and J. C. Palumbo. 2024. Chlorantraniliprole Resistance Associated with Diamondback Moth (Lepidoptera: Plutellidae) Outbreaks in Arizona Brassica Crops. Journal of Economic Entomology. toae212, https://doi.org/10.1093/jee/toae212.
Daytime and nighttime temperatures have risen well above the recent norm, with important implications for crop development, irrigation demand, and pest management.
Yuma Valley has experienced an unusually warm spring pattern since late February 2026. Based on AZMET Yuma Valley station data, daily maximum and minimum air temperatures from January through March 29, 2026, diverged markedly from the 2020–2025 pattern, with the greatest separation occurring during March. In the most recent period, daytime temperatures repeatedly rose into the mid-90s and above 100°F (Figure 1), while nighttime temperatures frequently remained near or above 60°F (Figure 2). Relative to the recent historical pattern, both daytime and nighttime conditions have remained consistently warmer than expected for this point in the production season.
This warming trend is agronomically important because crops respond not only to extreme temperatures but to cumulative thermal exposure over time. When both maximum and minimum temperatures remain elevated for prolonged periods, crop development accelerates, the growing season becomes compressed, and management schedules can shift quickly. In several vegetable production systems, this season’s heat pattern appears to be advancing crop maturity and harvest readiness by as much as three weeks. While earlier harvests may appear favorable at first, such rapid progression often reduces the amount of time the crop has to accumulate biomass and achieve full yield potential.
In desert vegetable systems, crop growth and maturity are strongly linked to heat-unit accumulation. Under warmer-than-normal conditions, crops move more quickly through vegetative development, canopy expansion, and market maturity. However, earlier maturity is not necessarily equivalent to better productivity. Yield depends not only on developmental timing, but also on the duration of active growth. Crops need adequate time to intercept sunlight, expand leaf area, produce carbohydrates, and partition assimilates into the harvestable portion of the plant. When the season is shortened by sustained heat, plants may reach harvest stage before fully developing the biomass needed for optimum size, weight, or quality. The result can be smaller plants, lighter fresh weight, reduced head development, and lower total marketable yield.
Warm nighttime temperatures may be especially important in explaining this response. Plants photosynthesize during the day, but they respire continuously, including throughout the night. When nights remain warm, respiration rates increase, and a larger proportion of the carbohydrates produced during the day is consumed for maintenance rather than retained for growth and yield formation. This reduces carbon-use efficiency and limits dry matter accumulation. In practical terms, the crop may mature earlier while simultaneously losing some of its ability to build harvestable biomass. Warm nights also reduce the recovery period plants normally experience after hot daytime conditions, creating sustained thermal stress across the full 24-hour cycle.
The recent heat pattern is also likely increasing crop water demand. High daytime temperatures elevate evapotranspiration, and warm nights can prolong plant metabolic activity and maintain greater atmospheric demand. As a result, irrigation requirements may now be higher than expected for late March. Fields managed under fixed irrigation intervals may begin to experience short-term moisture deficits if irrigation is not adjusted to current weather conditions and crop demand. Even brief periods of water stress during rapid growth can reduce cell expansion, canopy development, and final yield. At the same time, excessive irrigation in response to heat can create additional problems, including nutrient leaching, fluctuating root-zone aeration, and reduced fertilizer-use efficiency. Under these conditions, irrigation decisions should be based on crop stage, soil moisture status, and weather-based demand rather than on calendar assumptions alone.
From an IPM perspective, abnormal warming may also alter pest pressure and the timing of management decisions. Higher temperatures can accelerate insect development, shorten generation times, and increase the rate of population growth. At the same time, crop phenology is also advancing more quickly, which narrows the window for scouting, threshold-based treatment decisions, and timely intervention. In effect, both the crop and the pest may be moving ahead of schedule. Heat-stressed plants may also be less tolerant of pest injury because they are already operating under shortened growth duration and higher respiratory demand. Under these conditions, pest damage that might otherwise have been manageable under normal spring temperatures could become more economically significant.
Other agronomic practices may also need adjustment. Nutrient demand can shift when crop development accelerates, and fertilizer programs designed around the normal seasonal calendar may no longer align well with actual crop uptake. Harvest logistics may also be affected if multiple planting blocks mature earlier than expected. Labor scheduling, harvest sequencing, cooling, and market timing can all become more difficult when crop development is compressed. Thus, the current warming pattern should be viewed not only as a temperature anomaly but as a whole-system production issue affecting physiology, water management, pest pressure, and field operations.
Bottom line
The abnormal warming pattern that developed in Yuma Valley from late February through March 2026 may be substantially shortening the vegetable production window. Although earlier maturity may move harvest ahead of schedule, the physiological and agronomic costs can be considerable. A compressed season reduces the time available for biomass accumulation, while elevated nighttime temperatures increase respiration and reduce carbon retention. Together, these conditions may lower yield potential, increase irrigation demand, intensify pest management pressure, and complicate agronomic decision-making across the production system.
Figure 1. Daily maximum air temperature recorded at the AZMET Yuma Valley
station from January 1 through March 29, 2026, compared with the 2020–2025
temperature pattern.
Figure 2. Daily minimum air temperature recorded at the AZMET Yuma Valley
station from January 1 through March 29, 2026, compared with the 2020–2025
temperature pattern.
VegIPM Update Vol. 17, Num. 14
July 8, 2026
Results of trap catches below!!
Whitefly: Adult activity remains steady across locations; above average for this time of the year. Historically, whitefly numbers peak in July.
Thrips: Adult thrips activity decreased over the last two weeks. About average for this time of the year. Historically, thrips numbers remain low until Sept-Oct.
Diamondback Moth: No diamondback moths have been collected in the traps since May 19th. Based on the past six years summer collection data, no DBM is collected in the traps in the summer months (Jun-Aug) until September.
