Summer is finally over. Brassica transplants are in the ground, and direct-seeded broccoli and lettuce plantings are now beginning.  In the past week, I’ve observed or received reports from PCAs of key insect pests beginning to show up (or not) on melon and early produce crops in the desert.   
 
Seedling pests:  Flea beetles (FB) are beginning to show up in transplanted crops like they always do, but pressure has been light so far. We haven’t seen much in our experimental plots at YAC either.  Remember, FB adults lay eggs in the soil of their favored local host plants (i.e., alfalfa, cotton, purslane, pigweed and nightshade) where larvae feed on the roots to later emerge as adults. So, keep in mind, the source of that FB infestations hitting your new stands may not just be freshly cut hay, defoliated cotton, or disked weeds. In some areas (Yuma Valley), crickets seem to be very abundant. Crickets like moisture and are often found under sprinkler pipes but can also be found in cracks in soils around fields or in drainage areas. 
 
Bagrada bug:    We’ve already had reports of bagrada bug adults on two transplanted cauliflower fields in Dome Valley. Not sure whether they arrived with the transplants or are moving from surrounding crops. However, it’s still early and they might surprise you as the season progresses.   Look for those fresh feeding signs on cotyledons and young leaves.  Experience suggests that they are most abundant after the humidity breaks.
 
Lepidopterous Larvae (worms):   Worm pressure seems to be below normal. Trap catches so far show that Cabbage looper moths are almost non-existent, and no reports on melons to date. They should pick-up as we approach October. No reports of Beet armyworm larvae on the earliest transplants yet, and areawide pheromone traps suggest that moth activity is below normal. But they will show up sooner or later, so get ready.  You have numerous insecticide alternatives at your disposal to control them.  Have had a couple of reports of Diamondback moth larvae on newly transplanted brassica crops. However, we’ve yet to capture moths on pheromone traps which suggests that adult immigration on high altitude winds associated with storms has not occurred. Remember, DBM disappear each summer and reestablish on desert crops via transplants or migrate in on monsoon/tropical storms. I strongly stress that you check your Cole crops closely this fall, particularly following storms or on plants originating from coastal CA. 
 
Whiteflies:       Area wide sticky trap captures have been about normal for early September, but whiteflies can migrate long distances on high winds. Adult numbers increased on my melon plants last week and remain high. Reports in area melons range from light to moderate numbers so far, but there is still a lot of cotton out there yet to be picked. The good news is there are several insecticide alternatives to control them in produce. 

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%). Variety: Deluxe (HMX2595) was seeded, then sprinkler-irrigated to germinate seed on March 20, 2024on 84 inches between bed centers. All other water was supplied by furrow irrigation or rainfall. Treatments were replicated five times in a randomized complete block design. Each replicate plot consisted of 25 ft of bed. Treatment beds were separated by single nontreated beds. Treatments were applied with a tractor-mounted boom sprayer that delivered 50 gal/acre at 100 psi to flat-fan nozzles spaced 12 in apart. 

Spray treatments were done on 05-21-2024, 05-31-2024, 06-07-2024 and 06-14-24. Powdery mildew was first seen on 06-05-24. Please see excel file for additional details.  

Disease severity of powdery mildew (caused by Sphaerotheca fuliginea and S. fusca) severity was determined 6-17-2024 by rating 10 plants within each of the four replicate plots per treatment using the following rating system: 0 = no powdery mildew present; 1 = one to two mildew colonies on leaves  ;2 = powdery mildew present on one quarter of leaves; 3 = powdery mildew present on half of the leaves; 4 = powdery mildew present on more than half of leaf surface area ; 5 = powdery mildew present on entire leaf. These ratings were transformed to percentage of leaves infected values before being statistically analyzed.

The data in the table illustrate the degree of disease control obtained by application of the various treatments in this trial. Most treatments significantly reduced the final severity of powdery mildew compared to nontreated plants. Quintec, Merivon, Tesaris, Luna Sensation, and V6M-5-14 V gave the best disease control. Phytotoxicity symptoms were not noted for any treatments in this trial.

ANR Webinar 10/17 click link for details.

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.

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

Diamondback moth:                

• Adult activity increased in all trapping locations over the past 2 weeks, except in the south Yuma Valley.
• Compared with previous seasons, DBM populations about average for this time of the year.
• DBM captures were highest in Bard, north Yuma Valley and Gila Valley in the past 2 weeks and averaged about 4 moths / trap / night.
• Average moth captures across all traps last week averaged slightly more than 3 moths / trap/ night

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

Corn earworm: CEW moth activity increased a bit in the past 2 weeks but remains well below average for late spring.

Beet armyworm: Moth counts increased slightly, but remain very low consistent with seasonal temperatures, and below average for this point in the season.

Cabbage looper: Significant increase in activity in Dome Valley, Gila Valley and Tacna, but moth counts remain unusually low for this time of year, as they have all season.

Whitefly:  No adult movement recorded across all locations and overall low numbers consistent with temperatures.

Thrips: Thrips adult movement beginning to pick up considerably, particularly in Yuma and Dome Valleys. Movement is below average for late March.

Aphids: Seasonal aphid counts down considerably compared with the Feb and Jan.  Counts highest in Bard and Gila Valley.  Below average movement for this time of year. Majority of species found on traps were green peach aphid.

Leafminers: Adult activity up slightly in some locations, but well below average for late season.