Some major events and developments have taken place recently in the Colorado river water shortage arena.  As a result, we are entering into a series of substantial and complicated legal aspects associated with the Colorado River situation.  
As part of the SW Ag Summit that is taking place in Yuma this week, we are conducting a breakout session on Thursday, 23 February 2023 titled “Colorado River Water Shortage: Agricultural Perspectives”.
This session will provide a brief review of the background and current situation on the Colorado River and very importantly it will include perspectives from members of the lower Colorado River agricultural community including the Palo Verde Valley, the Imperial Valley, and the Yuma area irrigation districts.   
The program outline is as follows:
 
 
2023 Southwest Ag Summit
Educational Program
Thursday – February 23, 2023
 
Morning Breakout Session
9:30 am – 11:30 am
 
 

1. Colorado River Water Shortage: Agricultural Perspectives       

(Requesting 2 CCA)
 
9:30 – 10:00    Colorado River Water Shortage: Introductory Overview      
                                    Jeff Silvertooth, University of Arizona, Tucson, AZ
 
10:00 – 10:30 Colorado River Water Shortage: Palo Verde Valley Perspective
Bart Fisher, Fisher Ranch, Blythe, CA           
 
10:30 – 11:00  Colorado River Water Shortage: Imperial Valley Perspective
                        Larry Cox, Lawrence Cox Ranches, Brawley, CA
 
11:00 – 11:30  Colorado River Water Shortage: Yuma Perspective
Elston Grubaugh, Wellton Mohawk Irrigation & Drainage District, Wellton, AZ 
 
            Moderator:      Jeff Silvertooth

Bacterial leaf spot is caused by the bacterium, Pseudomonas syringae pv. Aptata. Hosts of the pathogen include Table beet, Sugar beet, Spinach, Swiss chard, Snap bean, Dry bean, Cantaloupe, Pumpkin, Squash, Lettuce, and Pepper.
 
Significance
Bacterial leaf spot is most commonly found affecting table beet at early stages of growth. This may be because younger plants are more susceptible. It may also be related to the prevalence of cool, wet conditions at the beginning of the cropping season. These conditions are most conducive to infection and disease development. The disease may affect green leaf area in developing seedlings and in severe cases can lead to plant death. Diseased leaves will lead to weakened seedlings which may affect transplant success. Bacterial leaf spot does not directly affect root quality.

Figure 1. Bacterial leaf spot caused by Pseudomonas syringae pv. aptata of
table beet: (left) Small focus of the disease, and (right) 2-6 true leaf stage of
plants affected by the epidemic.

Symptoms
Bacterial leaf spot symptoms are irregular in shape and black to brown in color. The spots may occur across the leaf surface but have a tendency to occur on the leaf edges. Lesions are water-soaked not often accompanied by chlorosis (yellowing). Lesions may initially be small (up to ¼ inch in diameter) but if conditions are conducive may rapidly expand and coalesce but do not cross major veins. The leaf is usually puckered and deformed around the lesions, especially if they occur on the margins (Fig. 2). When the disease is severe, the affected the tissue may also tear giving the appearance of abiotic damage such as hail.

Figure 2. Symptoms of bacterial leaf spot on table beet (cv. Merlin). Note the
black color of the lesions and puckering and deformation of the leaves around
the symptoms.

Bacterial leaf spot symptoms may be confused with other fungal foliar diseases (e.g. Cercospora and Phoma leaf spots; see complementary fact sheets for these diseases) and insect damage (e.g. thrips). Bacterial leaf spot lesions do not have black pin-head, fungal structures across the lesions as found in Cercospora leaf spot. Phoma leaf spot lesions also have small, black structures within the lesions but found in rings and usually accompanied by an ooze of spores.
Disease Cycle
Figure 3. Schematic diagram of the potential sources of Pseudomonas syringae pv. aptata inoculum which may contribute to Bacterial leaf spot epidemics in table beet.
P. syringae pv. aptata may be introduced to the table beet crop through several ways (Fig. 3). P. syringae pv. aptata is seedborne and infested seed is a common means of pathogen introduction into table beet fields. The pathogen can also be present in the infested crop residues from the previous season as well as the alternative hosts. Alternative crop hosts include typical Chenopods (e.g. spinach, sugar beet, and Swiss chard) but also other non-related species including beans, cucurbits, and lettuce. Cool temperatures between 45-60°F and wet conditions typical of those that occur in early spring in upstate New York are conducive for pathogen infection and disease development. These conditions are similar to those that predispose table beet also to Phoma leaf spot. The pathogen can spread within the field through infested seed and irrigation water.
Disease Management
One of the most critical factors to achieve management of bacterial leaf spot is the use of certified seeds (Fig. 4). Other factors that will also contribute to reducing the initial inoculum and hence risk of disease include: (i) tillage to bury plant residues to promote breakdown, (ii) rotation between host crop species of at least three years; and (iii) drip or furrow irrigation to avoid dispersal of the pathogen through water splash. Currently, little is known of differences in cultivar susceptibility to bacterial leaf spot. Anectodal reports have described severe epidemics in cvs. Merlin, Boro, and Pablo.

Figure 4. Complementary practices towards the management of Bacterial leaf spot of table beet.
In-season control. If bacterial leaf spot is severe, applications of copper-based products should be considered to prevent disease spread. There are a range of conventional and OMRI-listed copper-based products available, including: Cueva (copper octanoate; FRAC M1), Badge X2 (copper oxychloride + copper hydroxide; FRAC M1), and Kocide 3000-O (copper hydroxide; FRAC M1). Remember to check the label for rates, re-entry intervals, and pre-harvest intervals applicable to your state and crop. Avoid applying copper-based products on transplants before hardening off, and in high temperatures due to the risk of phytotoxicity.
 
Source: 
https://www.vegetables.cornell.edu/pest-management/disease-factsheets/bacterial-leaf-spot-of-table-beet/

Keeping up to date with the latest developments in automated weeding machines is challenging. It’s a very fast-moving space with significant private and public investment. At the 2023 Southwest Ag Summit “Innovations in Weed Control Technologies” breakout session, university experts and cutting-edge innovators will provide updates on the latest advances in high precision smart spot sprayers, towed automated weeders and autonomous weed pulling robots (agenda below). The session will be held TOMMOROW Thursday, February 23^rd from 9:30-11:30 pm at Arizona Western College in Yuma, AZ.
As I mentioned in the last newsletter, we’ll also be demoing our band-steam applicator for controlling soilborne diseases and weeds at the Southwest Ag Summit Field Demo Day (Fig. 2). It is simpler in design and has a higher capacity steam generator as compared to our first prototype. This will increase travel speed and thereby work rate. The event is scheduled for TODAY, Wednesday, February 22^nd from 10:00 am – 4:30 pm.
For more information about the Southwest Ag Summit, visit https://yumafreshveg.com/southwest-ag-summit/.
Hope to see you there!

Fig. 1. “Innovations in Weed Control Technologies” breakout session agenda at
the 2023 Southwest Ag Summit. Session will be held Thursday, February 23^rd at
Arizona Western College, Yuma, AZ.


Fig. 2. Band-steaming demo plots prior to planting in preparation for the 2023
Southwest Ag Summit Field Demo Day, February
22^nd (https://yumafreshveg.com/southwest-ag-summit/).

On Thursday February 23, 2023, the afternoon the SWAS breakout sessions dedicated to Integrated Weed Management and Impact to Desert Agriculture (Located at AS 113) will have participation from Jesse Richardson from Corteva Agriscience.  He will give us the historic perspective of Kerb Chemigation research.  Samuel Discua Duarte from the U of A has conducted a weed survey for INSV virus hosts for a couple of years and will inform the results in his lecture.
Jose L. Carvalho de Souza from the University of Arizona Maricopa Agricultural Center will give us a lecture on the management of Palmer amaranth, the King of weeds. And I will inform some of the results from our Prefar trials at the Yuma Agricultural Center.
You are cordially invited to the session as well as the other breakout Southwest Ag Summit sessions organized by our Arizona Vegetable IPM Team…hope to see you there!.
 
 

INTEGRATED WEED MANAGEMENT AND IMPACT TO DESERT AGRICULTURE
(Requesting 2 CEU and 2 CCA)
Location: AS 113
Sponsor: Green Valley Farm Supply, Inc.

1:30-2:00p Insights from Early Kerb Chemigation Research
Jesse Richardson, Corteva Agriscience, Mesa, AZ

2:00-2:30p Survey of Weeds as Hosts of INSV in Yuma County – Results From Two Year Survey
Samuel Discua Duarte, University of Arizona, Yuma,AZ

2:30-3:00p Integrated Weed Management – Palmer Amaranth
Jose L. Carvalho de Souza, University of Arizona, Maricopa, AZ

3:00-3:30p Herbicide Evaluations at Yuma Agricultural Center
Marco Pena, University of Arizona, Yuma, AZ

Moderated by Marco Pena

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