As you plan for the season, it’s important to know how EPA’s new Endangered Species Act risk mitigations might impact pesticide planning and use.

As EPA registers new pesticides or reviews registrations of existing ones, they evaluate expected impacts on federally listed threatened and endangered species. When a pesticide is predicted to adversely affect a listed plant or animal species or their critical habit, one or both of two outcomes are possible:

1. Broad label requirements to reduce potential impacts of pesticides on listed species and other non-target organisms by reducing runoff and/or spray drift.
2. Geographic-specific use limitations communicated through

Bulletins Live! Two.

As you plan your pesticide program, be sure to review current product labels to anticipate any endangered species requirements.

 

Runoff Mitigation Points

• Does the pesticide require runoff / soil erosion mitigation points? Check the pesticide label. (Tip: Look for a header such as “Mandatory Runoff Mitigation” or search for the word “points.”)

• Exemptions. No points are needed for fields with systems that capture runoff and discharge, certain application methods such as soil injection, spot treatment < 1,000 sq. ft., or chemigation applied under non-permeable plastic mulch.

• Yuma County applications qualify for 6 mitigation relief points.

• If more points are required, consult EPA’s Mitigation Menu website and consider using their Worksheet to ensure adequate points can be attained to use the pesticide. Mitigation points are based on several factors, field characteristics, participation in conservation programs, application parameters, and more.

 

Endangered Species Bulletins

• Is an Endangered Species Protection Bulletin required? Check the label under “Directions for Use.” If required, access the Bulletins Live! Two website. Enter or navigate to the application site using the map; select month and year of application; enter the product EPA Registration Number.

• Print bulletin. If a Pesticide Use Limitation Area (PULA) appears in the map view, click the colored area of the PULA to turn the red “Printable Bulletin” button green. Click the green button to download or print the bulletin.

• If your field(s) are located inside a Pesticide Use Limitation Area (PULA), follow the bulletin guidelines for limitations on pesticide use. If your fields are outside the PULA, follow label requirements and keep a copy of the bulletin for your records.

• PULAs in Yuma are found along the Colorado and Gila Rivers in production areas for certain Dicamba products. These require both a 310-foot in-field wind-directional spray drift buffer and a 57-foot omnidirectional in-field buffer for fields found within the PULA.

• Plan ahead. You can access and print Bulletins up to 6 months prior to an application. Consider entering registration numbers for the main pesticides in your program, then generate a bulletin for each month and year you expect to apply the pesticide. Keep these with your records in case an application is needed.

 

Want a Deep Dive on This?

There will be a Laws & Regulations CEU opportunity on September 3 in Yuma, where this topic will be covered in detail.

• 4 CA DPR L&Rs CEUs and 4 AZ CEUs (pending approval)
• This is a great chance to learn how to stay compliant and ask questions directly.

 

For more info, contact Dr. Al Fournier at Fournier@cals.arizona.edu

John Wesley Powell, the Civil War veteran who lost most of his right arm at the Battle of Shiloh, led his first expedition down the Green and Colorado Rivers, including the Grand Canyon in 1869.  This provided the first exploration of the Colorado River basin by Americans of European descent and it began the process of understanding the nature of western territories of the United States, including Arizona (Figure 1).
 
The degree of aridity of this region was very strongly impressed upon Powell and he spent much of his life working to educate law and policy makers of the conditions prevalent in the western U.S.  He worked diligently with lawmakers, government experts, and citizens to communicate the fact that the development of the western territories, which the nation was rapidly embarking on after the Civil War, would be limited due to the lack of water.  His comments to the Montana Constitutional Convention in 1889 “All the great values of this territory have ultimately to be measured to you in acre feet” is a good example of his basic message and it has proven to be quite prophetic in our experiences of living and working in the desert Southwest in the 20^th and 21st centuries.
 
Powell became the second director of the U.S. Geological Survey (USGS) from 1881 to 1894.  In this and similar capacities, he constantly advocated for policies for the development of the arid West that were consistent with the prevailing arid conditions.  As the lands in the western U.S. were being developed, the need for land “reclamation” was recognized.  It was 120 years ago this week, on 17 June 1902 that Theodore Roosevelt signed the Reclamation Act and the U.S. Reclamation Service (USRS) was formed within the USGS under the Secretary of the Interior Ethan Allen Hitchcock.  The new USRS was given the responsibility of studying potential water development projects in each western state with federal lands.  Revenue from the sale of federal lands was the initial source of the USRS funding.
 
Thus began the process of the USRS in the development of about 30 western water projects between 1902 to 1907.  In 1907, the Secretary of the Interior separated the USRS from the USGS and created the Bureau of Reclamation (BoR) as a distinct entity within the Department of the Interior.  The Boulder Canyon (Hoover Dam) project was authorized in Congress in 1928 and funded by general funds appropriated by Congress to the BoR, and from that the development of Lake Mead began.  Lake Mead is the main storage reservoir for the lower basin of the Colorado River.
 
In the late 19^th and early 20^th centuries, efforts in the western U.S. to develop lands for agriculture encountered problems with lands and soils that were found to be unsuitable for irrigation, often due to salinity, sodicity, and drainage problems.  The “reclamation” of these lands became an important part of the BoR objectives and operations.  All this development was dependent on the availability of water and good land and water management capacities.
 
During the 20^th century, the BoR was responsible for some tremendously large and ambitious projects, including Boulder Dam, Grand Coulee Dam, Glen Canyon Dam, and many others.  Today, the BoR operates in 17 western states with water and electrical power projects with more than 600 dams, reservoirs, powerplants, and canals.  The BoR is the largest wholesaler of water in the U.S. and supports irrigation water storage and conveyance throughout the west on farmlands that produce more than 60% of the nation’s vegetables and 25% of the fruit and nut production in the country. The BoR is the second largest producer of hydroelectric power in the U.S. with 53 powerplants.  The western U.S. development and population is heavily dependent on the BoR water and power works.
 
In Arizona and the desert Southwest, the lands and people here today have a very close relationship to the BoR for water and electrical power.  All the lands along the mainstem of the Colorado River and the Central Arizona Project (CAP) are intimately connected to the BoR.  Our efforts to deal with the water shortages on the entire Colorado River system are some of the greatest challenges this region and the BoR have faced since the early days of development in the 19^th century.  
 
Thus, there are many participants in the process of dealing with the current water shortage on the Colorado River system, including the U.S. Department of the Interior, the BoR, and all the basin states.  An accentuating feature of the current water shortage on the Colorado River is due to the fact that for the past 22 years, the average annual flow in the Colorado River has been ~ 12.4 million acre-feet (maf) while the Colorado River water is budgeted for a total of 16.5 maf of allocations between U.S. states and Mexico. 
 
Essentially, all of us living in the desert Southwest are in this together; including agricultural, urban, and tribal entities.  All parties involved must work together to resolve this disparity between the water that the river is providing and the greater amount that is desired and allocated.  The issues and general situation that we are facing has an urgency that requires immediate attention.  I remain hopeful that we can meet the challenges of our time as our predecessors did in the past.

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 maybe 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. Anecdotal 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/

Vol. 13, Issue 05, Published 3/09/2022
A couple of weeks ago, I presented summarized results of our multi-year trials examining the use of band-steam to control sclerotinia lettuce drop, Fusarium wilt of lettuce and in-row weeds at the 2022 Southwest Ag Summit. Band-steam has been described in previous UA Veg IPM articles (Vol. 12 (5), Vol. 11 (15). Briefly, the concept behind band-steam is to disinfest narrow bands of soil centered on the seedline using high temperature steam prior to planting.
Results varied as you might expect depending on field conditions, but in general, injecting steam pre-plant was found to provide very good on weed control (85-100%), and reasonable control of sclerotinia (up to 70%) and Fusarium (>40% when initial inoculum levels were moderate). Crop yield increases of 24% to more 40% were found in trials (5) conducted in fields with varying levels of disease history. Energy requirements and fuel costs were high (~$900/acre) when initial soil temperatures were low (50°F, winter), but much more reasonable (~178/acre) when initial soil temperatures were high (110°F, winter).
We concluded that band-steam may be a viable technique for controlling soilborne pests in high value conventional and organic vegetable crops, particularly if steam is applied when initial soil temperatures are high and the significant yield increases found in our studies can be realized at the field scale level. The presentation was uploaded to YouTube where you can find more specific details and to see the band-steam applicator in action. To see the presentation, click here or on the link below.
Acknowledgements
This work is partially funded by the Arizona Iceberg Lettuce Research Council, Arizona Specialty Crop Block Grant Program and USDA-NIFA Crop Protection and Pest Management Program.

Dacthal was first registered in 1959 but like most older products that are still used, we are constantly adapting it to our changing cultural practices. Dacthal is a mitotic inhibitor and kills germinating weeds by stopping cell division. This is the same mode of action as many other preemergence herbicides such as Trifluralin, Prowl, Balan, Kerb and others but its chemistry and how it moves in the soil and plant are different. Dacthal is absorbed by both shoots and roots of germinating seedlings although most of the activity is from shoot absorption. When absorbed by the shoots, it will move upward into the plant. It is not absorbed by foliage and can be safely applied over the crop. Dacthal has a strong affinity for soil and adsorbs strongly to soil particles. If Dacthal is applied to dry soil, it sometimes will not work because the herbicide it stuck on the soil and not available to kill weeds. Conversely, if the soil is saturated, it may not be adequately incorporated. The best time to apply Dacthal is when the soil is moist but not saturated. When Dacthal was first being developed it was tested for use on lettuce.If it is sprayed on or chemigated it will cause severe injury to lettuce. If it is mechanically incorporated it is surprisingly safe to lettuce. It is fairly broad spectrum but weak on mustards.

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.