University of Arizona Extension is offering two in-person CEU events at the Yuma Ag Center to help PCAs lock in their hours before the season hits full swing:

Fall IPM Update
Date: Tuesday, August 12
Time: 7:00–10:00 AM
Location: Yuma Agricultural Center
Credits: 2 AZDA | 2 CA DPR | 2 CCA (approved)
This session will cover current IPM issues in desert vegetable crops. Breakfast will be provided. Please RSVP to help us plan for food by emailing Robert Masson: masson@arizona.edu

2025 Laws & Regulations Update
Date: Wednesday, September 3
Location: Yuma Agricultural Center
Credits: 4 CA DPR Laws (requested) | AZDA hours pending
This session will focus on pesticide laws, safety, and compliance updates relevant to licensed PCAs.

Take advantage of these local opportunities to complete your CEUs before the season gets into full swing.

In arid and semi-arid regions, water is our first limiting factor in a crop production system, followed closely by bio-available nitrogen (N).  Thus, our management of water and N are critically important to produce a healthy crop with good yields and quality.
 
Water and nutrient demands coincide with the fruiting cycle and efficient management of irrigation water and plant nutrients is enhanced by tracking crop development in the field.  The use of heat units (HUs) with 86/55 ^oF upper and lower thresholds can be applied to warm season crops in the desert Southwest in relation to the thermal environmental impacts on the development of all crop systems (Brown, 1989), including chiles, (Figures 1 and 2).
 
Crop Phenology Relationship to Water and Nitrogen Demand
 
Phenological guidelines have been developed for many crops, including New Mexico type chiles (Soto-Ortiz and Silvertooth, 2007 and Silvertooth, et al, 2010; Figure 1).  This phenological guideline can be used to identify or predict important stages of crop development that impact physiological requirements.  For example, a phenological guideline can help identify stages of growth in relation to crop water use (consumptive use) and nutrient uptake patterns (Figure 3).
 
This information allows growers to improve the timing of water and N inputs to improve production efficiency.  For some crops or production situations HU based phenological guidelines can be used to project critical dates such as harvest or crop termination.  Many other applications related to crop management (e.g., pest management) can be derived from a better understanding of crop growth and development patterns.

Figure 1.  Typical relationship between the rate of plant growth and development
and temperature.  Growth and development ceases when temperatures decline
below the lower temperature threshold (A) or increase above the upper
temperature threshold (C).  Growth and development increases rapidly when
temperatures fall between the lower and upper temperature thresholds (B).


Figure 2.  Basic phenological guideline for irrigated New Mexico-type chiles.

References
Brown, P. W.  1989.  Heat units.  Bull. 8915, Univ. of Arizona Cooperative Extension, College of Ag., Tucson, AZ.
Silvertooth, J.C., P.W. Brown, and S. Walker.  2010. Crop Growth and Development for Irrigated Chile (Capsicum annuum).  University of Arizona Cooperative Extension Bulletin No. AZ 1529
Soto-Ortiz, R. and J.C. Silvertooth.  2007. A Crop Phenology Model for Irrigated New Mexico Chile (Capsicum annuum L.) The 2007 Vegetable Report. Jan 08:104-122. 

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

At the 2024 Southwest Ag Summit Field Demo a couple of weeks ago, many of the latest technologies were demonstrated in the field. Most were related to pest control. Several of the technologies demonstrated or on display at the event are brand new to the Yuma, AZ area. The new technologies presented included an implement designed for cultivating high density crops (Fig. 1a), a field scale drone sprayer (10.6 gal) (Fig. 1b), a high precision spot sprayer (Fig. 1c) and a self-propelled machine that disinfests soil prior to planting using steam. Updated versions of laser weeders, camera-guided cultivators and smart, automated in-row weeding machines (mechanical) were also demonstrated. Over the next several years, it will be interesting to watch the technologies in this space evolve further and become integrated into our cropping systems.

Fig. 1. New pest control technologies demonstrated/on display at the 2024
Southwest Ag Summit Field Demo included a) Oliver¹ high density cultivator b)
DJI Agrospray T40 drone sprayer c) Ecorobotix ARA high precision spot sprayer
and d) UC Davis/University of Arizona self-propelled steam applicator for
disinfesting soil prior to planting.

[1] Reference to a product or company is for specific information only and does not endorse or recommend that product or company to the exclusion of others that may be suitable.

The Yuma IPM Team has received requests for herbicide efficacy data generated locally for Onion and Broccoli. 
We are currently doing some evaluations for direct seeded broccoli. Some of the treatments suggested by PCAs and growers are Devrinol DF XT at the rate of 1.0 and 2.0 lb, also Devrinol 2-XT at the rate of 1.0 and 2.0 qt. Additional preemergence herbicides included in the trials are Prefar 6 qt, Trifluralin 1.5 pt. Other treatments included are Goal Tender and Prowl with a directed application at 3-5 leaves. In a separate broccoli test we are looking at different incorporation timings of Devrinol due to some stunting issues reported. Our trial includes 12, 24, 36 hour sprinkler irrigation incorporation times for the liquid and dry formulations. Phytotoxicity will be evaluated and reported to you in this newsletter and University of Arizona Workshops.
 
For onions we established trials including treatments suggested such as Ethotron SC at 32 fl oz to a fine soil. Also included Prefar, Dual Magnum and Treflan preemergence. We will compare with Outlook plus Prowl and Goal Tender at 3 leaf stage.
Additionally, Corteva Agriscience is also focused in providing some options for weed control in both broccoli and onions. Some of their products been evaluated at the Agricultural Center are Rinskor (Hulk) and Enversa at post and preemergence. 
We thank you for your treatment suggestions, which are incredibly helpful for designing the experiments we are conducting. We are looking forward to sharing the results with you.

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.