In a recent update, we anticipated that PCAs would soon begin finding aphids infesting local lettuce and cole crop fields. Thus far, we have not found any colonizing aphids and have spotted only an occasional alate (winged adult). Timing of aphid colonization in leafy vegetables varies by species, and depends largely on temperature, rainfall and planting dates. However, my experience over the years, as well as observations from numerous field trials, suggests that aphid species that infest leafy vegetables are historically most severe on crops planted from mid-November through December. Of course, there are exceptions to the rule and aphids can occur when least expected. Consequently, you should begin planning now for spring aphid management. Growers and PCAs have effective options for aphid management on spring leafy vegetable crops. First, there is the responsive approach that relies on foliar insecticide sprays to reduce aphid numbers when they are found on crops. A number of insecticides are available that have cost-effective activity against aphids when applied as foliar sprays targeted at aphid populations as they begin colonizing plants. There is also the preventative approach where growers can apply neonicotinoid insecticides at-planting, 1.5 to 2 inches below the seedline. The insecticide is taken up by the plant roots, systemically translocated throughout young plants for several weeks following emergence, and ultimately prevents aphid colonization early in plant development. Both approaches can be very effective, and both can be used on the same field. Among the neonicotinoids, imidacloprid has been the standard soil insecticide applied on spring lettuce for aphid control for 20 years and continues to provide long residual control when used properly. More recently, Movento, with its excellent systemic activity against aphids via foliar application, has been incorporated into lettuce IPM programs along with other novel insecticides with aphid activity. However, the question has recently been posed: Which approach to aphid management is better? Our research suggests a combination of both; imidacloprid applied at planting, followed by a foliar insecticide(s) if needed under heavy late season pressure. For more information on this topic please visit the research report - Aphid Management on Head Lettuce Using Imidacloprid and Foliar insecticides

The continuous development, testing, and incorporation of technology in agriculture is amazing.  I recently attended a western agricultural conference and when visiting the industry displays and booths, I was impressed with the new technologies that are coming into the agricultural arena.
 
Technological devices are tools and like all other tools, they are put to their best use in the hands of skilled craftsmen.
 
We have many excellent examples of technological tools in the crop production systems of the desert Southwest.  A basic example comes from the equipment used to till the fields, prepare a good seedbed, and then to plant a new crop by seed or transplant.  Excellent articles are provided in this newsletter on this topic regularly.  We tend to take this kind of equipment for granted until you must do the job by hand or with older technology.
 
Any new technology needs to be fully tested and demonstrated before anyone can expect it to be appropriately implemented.  That involves communicating the background, purpose, and utility of any new technology.  The cost/benefit ratios need to be worked out and presented.  A critical step in implementation is demonstration and establishing prima facie evidence to support the value of the new technology.  Testimonials are nice but there needs to be solid evidence to support claims of merit.  In science ideas demand testing and the presentation of proof.
 
A lot of emphasis recently has been placed on the technology and new tools available for soil-plant-water management and irrigation management.  There is a tendency for some people to think that our problems can all be solved with crop water management if we would just use the right technology.  In my view, some of the new irrigation technology is great and it can potentially be very useful in managing crop irrigation in the field.  But technology itself is not a panacea.
 
Despite the technological advancements that we do use and benefit from, the best potential improvements are dependent upon the skill and expertise of the farmers or field managers involved.  The skill set required to plant a crop, get a good stand, manage it to the proper level of maturity, harvest the crop, and then get it to market is indispensable and the responsibility comes down to individual farmers and farmer managers.  
 
The successful management of irrigation technology is totally dependent on the skill of the operator to make a personal assessment of a broad array of factors.  These factors include a review and assessment of the field in terms of crop condition and stage of growth, the soil moisture levels in relation to field capacity of the soil, the crop-specific irrigation requirements, allocating the appropriate amount of irrigation water needed, and the optimum time of application.
 
The ability of the farmer and/or farm manager to evaluate soils in the field regarding texture, water holding capacity, and current soil-water levels is essential.  Simple methods such as using a soil probe and estimating soil-water levels by feel with their hands remains and will continue to be a critical skill for farmers and field managers.  
 
I believe this is particularly true if one is trying to employ new technologies for irrigation management.  A good farmer can tell if the tools and technologies being employed are working properly.  They are the ones that usually take new tools to levels of use above and beyond what the developers were able to envision.
 
We all need a baseline in relation to crop-water management and the fundamentals will continue to be an important part of a farm manager’s skill set.  The new technologies may serve as good tools, but they will not replace the capacity of a farm manager to go into the field and figure out what is going on, put the tools or technologies to work appropriately, and not only apply them but do it well.  
 
Fundamentals are important, and they always will be.  This illustrates the fact that skilled professionals are essential in crop production. 

https://www.aglaw.us/agtech

This study was conducted at the Yuma Valley Agricultural Center. The soil was a silty clay loam (7-56-37 sand-silt-clay, pH 7.2, O.M. 0.7%). Spinach ‘Revere’ was seeded, then sprinkler-irrigated to germinate seed Jan 18, 2024 on beds with 84 in. between bed centers and containing 30 lines of seed per bed.  All irrigation water was supplied by sprinkler irrigation.  Treatments were replicated four times in a randomized complete block design.  Replicate plots consisted of 15 ft lengths of bed separated by 3 ft lengths of nontreated bed.  Treatments were applied with a CO₂backpack sprayer that delivered 50 gal/acre at 40 psi to flat-fan nozzles. 
 

Month	Max	Min	Average	Rainfall
January	68	42	54	1.14 in
February	73	47	59	0.50 in
March	77	50	63	0.31 in

 
Downy mildew (caused by Peronospora farinosa f. sp. spinaciae) was first observed in plots on Feb 19  and final reading was taken on February 26, 2024. Spray date for each treatments are listed in excel file with the results.   Disease severity was recorded by determining the percentage of infected leaves present within three 1-ft² areas within each of the four replicate plots per treatment.  The number of spinach leaves in a 1-ft² area of bed was approximately 144. 

The data (found in the accompanying Excel file) illustrate the degree of disease reduction obtained by applications of the various tested fungicides. Products that  provided effective control against the disease include Orondis ultra, Thrive 4 M, Fungout, Cevya, Eject and Zampro. No phytotoxicity was observed in any of the treatments in this trial.

Interested in the latest developments in automated weeding machines? There are a couple of opportunities at the upcoming 2024 Southwest Ag Summit to stay up to date. One is the “Ag Tech: Innovations in Weed Control Technologies” breakout session where university experts and cutting-edge innovators will provide updates on the latest advances in AI, laser weeding, high precision smart spot sprayers, robotic/automated weeders and band steam (agenda below). The session will be held Thursday, February 22^nd  from 1:30-3:30 pm at Arizona Western College (AWC) in Yuma, AZ.
The other is the Southwest Ag Summit Field Demo on February 21^st, where several of these technologies and other state-of-the-art automated weeders will be demonstrated operating in the field. The Field Demos will also be held at AWC. Breakfast will be served at 7:00 am and demonstrations begin at 8:00 am.
For more information about the Southwest Ag Summit, visit https://yumafreshveg.com/southwest-ag-summit/.

Fig. 1. Agenda for the “Ag Tech: Innovations in Weed Control Technologies”
educational session at the 2024 Southwest Ag Summit. The session will be held
Thursday, February 22nd at Arizona Western College, Yuma, AZ.


Fig. 2. 2024 Southwest Ag Summit Field Demo agenda. The event will be held at
Arizona Western College in Yuma, AZ.

In our last newsletter we talked about the importance of proper weed identification before making decisions on control measures. We mentioned some of the literature that the Vegetable IPM Team uses at the Yuma Agricultural Center.
An increasing number of PCAs and growers are using several phone applications for weed ID.
In this update I would like to share some data that was collected from a group of students of the 2024 PLS 300 Applied Weed Science class.
Professor Barry Tickes asked his students to download two phone applications and test the accuracy of the weed species ID. The recommended applications used were PlantNet and PictureThis Plant Identifier, which according to some  Pest Control Advisors are reasonably accurate.
We provided a display of 9 weeds to the students to take images and upload to the phone apps for ID and here are the results obtained:
 
Weed                                         PictureThis                  PlantNet
 
Annual bluegrass                            6                                        0
 
Creeping woodsorrel                      8                                        6
 
Nettleleaf goosefoot                       4                                        3
 
Prickly lettuce                                 8                                        0
 
Spiny sowthistle                              6                                        1
 
Spinach                                            8                                        6
 
Malva                                              6                                         1 
 
Silversheath knotweed                    5                                         0  
 
Littleseed canarygrass                     0                                         0        
 
       PictureThis Plant Identifier performed better than PlantNet in this evaluation. Interestingly in 2022 the weed science class evaluated PlantNet with results showing that 84.6 % of the time the application was correct. If you have another application that you recommend, please send it in your comments and we will share it with others in this newsletter.   

Get your free copy of the Weed Seedling Identification Pocket Guide at the Yuma Agricultural Center.

Area wide Insect Trapping Network   VegIPM Update, Vol. 15, No. 21, Oct 16, 2024

Results of pheromone and sticky trap catches can be viewed here.

Corn earworm: CEW moth counts increased in most traps; about average for early October.

Beet armyworm: Trap counts increased in most areas last week, and about average for early October.

Cabbage looper: Cabbage looper trap counts still most locations, below average for this time of the season.

Diamondback moth: Adult activity increasing, particularly in the Yuma and Dome Valleys.  Above average for this time of season.

Whitefly: Adult movement increasing Tacna, Dome Valley and Yuma Valley; overall about average for early October.

Thrips: Thrips adult movement picking up in all areas, overall activity above average.

Aphids: Winged aphids beginning to show up the north Yuma and Gila Valleys; about average for early October.

Leaf miners: Adult activity light in all areas, about average for this time of season