The beet armyworm (BAW) is the most common lepidopterous pest infesting lettuce throughout the desert southwest where larvae are most prevalent from August through November. Historically, PCAs have been able to effectively control this pest using available insecticides. Because many of the products have different modes of action (MOA) that can be alternated throughout the growing season, the rapid development of resistance by BAW to any of these insecticide compounds should not readily occur. In fact, resistance by BAW to insecticides has not been recorded in nearly 20 years in the desert as a result of the judicious usage of these insecticide chemistries. However, if an insecticide compound, or products with the same MOA, are used repeatedly for worm control in the same field, the risk of resistance increases significantly. This is particularly important with the Diamide group of insecticides (IRAC group 28) which can be applied as both foliar sprays and soil injections. With the recent registration of cyantraniliprole (Exirel and Verimark), PCAs now have eight different diamides insecticide products within the diamide chemistry (IRAC group 28) to choose from for worm control. Foliar uses include Coragen, Voliam Xpress, Voliam Flexi, Exirel, Belt and Vetica; Soil uses include Coragen, Durivo and Verimark. Applying these Diamide products to the soil at planting, and then following with foliar sprays of Dimades in the same field, can expose multiple generations of Lep larvae to the same MOA. This places increased selection pressure on populations. That’s not a good way to use these products if you want them to remain effective for more than a couple of years. Since the Diamides, as well as the other products currently available (Radiant, Proclaim, Intrepid, Avaunt), are critical to effective management of worms in leafy vegetables, PCAs should consciously avoid the overuse of any of these compounds. The most effective way to delay the onset of resistance by BAW in leafy vegetables is to consider the recommendations provided in the guidelines recently prepared entitled Insecticide Resistance Management Guidelines for Beet Armyworm in Lettuce.

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.

The autonomous agricultural robot industry is an incredibly fast-moving space. Startups, established companies and academic researchers are continuously putting forth new ideas and products. It’s hard to keep up with. In November of 2020, Future Farming (Misset Publisher, BV, Doetinchem, Netherlands) published a Field Robots Catalogue that provides a comprehensive overview of the state of autonomous ag robots. The article provides brief summaries of 35 autonomous ag robots that are currently commercially available. Along with a brief paragraph about what each robot does, the article presents information about how many robots from a particular manufacturer are actively being used, the cost of the machine, and links to a video of the device in action. Most of the robots are for weed management in vegetable crops. Kill mechanisms range from spot spraying to mechanical weed removal to electrocution.  Several of the robots featured are applicable and relevant to Arizona vegetable production, and some are currently operating in the U.S. If you’re interested in ag robots and want to get up to date, this article is an excellent resource and quick read. The article can be found at the link provided below.

Title: Future Farming Field Robots Catalogue
https://misset.com/field-robots/field-robots/
Publisher: Misset Publisher, BV, Doetinchem, Netherlands.

Contact herbicides are those that only affect the part of the weed that they “contact” They don’t move into or affect any other part of a plant. They were the first herbicides used and surprisingly, they still are better at controlling some weeds than any other products that have been developed. They usually control only small weeds with good coverage although some of them will kill large malva , Purslane and some other difficult to kill weeds. Goal, Sharpen, Treevix and Gramoxone, which are all contacts, will kill malva and purslane while systemic herbicides like Glyphosate and 2,4-D, misses them. Maestro or Bucril (Bromoxynil), also an old contact, will kill swinecress while many systemics like the growth regulators ,miss it. Glufosinate( Liberty, Rely) is a contact that is very broad spectrum and kills more grasses and broadleaves than many systemic herbicides. These all work very fast and in this age of immediate gratification ,you don’t have to wait long.  Most have little soil residual activity (except Goal, Chateau and a couple others) Goal and Chateau are contacts but used mostly preemergence to the weeds. They “ contact” the weeds when they emerge at the surface. which is a benefit where double or triple cropping is common. Most( again except Goal) are not volatile but will cause pretty clear contact injury when the spray moves to sensitive crops. Paraquat was registered in 1959 and is still a very useful tool for desiccating plants. Many restrictions have been put on its use because of its toxicity to humans.  Most contact herbicides are non-selective and will injure most living plant tissue. They are used selectively with directed spray or timing. Adjuvants are often required to increase absorption, spreading and sticking.

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; about average compared to previous years.
 
Cabbage looper:          
Cabbage looper counts increased to seasonal highs; slightly 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 negligible, average for late winter. 
 
Thrips:                          
Thrips adult counts increased in south Gila Valley, down in all other locations. Below average compared with previous years.
 
Aphids:                        
Aphid movement decreased in all area; below average for mid-March.
 
Leafminers:                  
Adults remain low in most locations, average for March.