ATTENTION PCAs please mark you calendars for Wednesday August 12, 2015. From 11:30am-2:30pm we will have a workshop for all PCAs titled: “A Multi-Crop Discussion on Chemical Use Maps for Whitefly Resistance Management”. Application for 3.0 Arizona CEUs was submitted. The event will take place at the University of Arizona Yuma agricultural Center conference room, lunch will be provided. We will send an announcement with the workshop agenda before the event. Thank you for your support! 

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.

Puncturevine is a weed that even the most avid environmentalist has a difficult time liking. Fortunately, it is not a native plant and there are products available to control it. It was brought to California from Asia, Africa and the Mediterranean region and has spread across the county. It can be a serious problem in orchards, turf and on ditch banks. It is a summer annual and will die from frost, but the seed heads are most troublesome when they have matured. Puncturevine (Tribulus terrestris) is in the caltrop family and has several common names including goatheads, Mexican sandbur, caltrop and many other names that cannot be printed here. It is appropriately named because of the hard spike like seed pods that can puncture tires injure animal feet and mouths. It commonly has four spikes that are arranged so that when three of the spikes are on the ground, the fourth will point upward. It can grow in dry areas but thrives in wet summers. The seed heads that you see now will germinate in the pod next spring. One plant can form a dense mat running 20 feet or more and produce up to 5000 seeds. Seeds can survive around 5 years. The most common way that it is controlled in residential areas is by pulling and hoeing. In large landscaped parks, schoolyards etc. herbicides can be useful. Triluralin and Balan applied in the spring prior to emergence will provide partial but not complete control. After it is established the systemic growth regulators like 2,4-D, dicamba and others will work but they will injure other broadleaf plants if they come in contact. Biological control of puncturevine is possible but it might take up to two years to work. There are two weevils: A seed weevil (Miclarinus lareynil) and a stem weevil (Micarlinus lypriformis) that are specific to puncturevine. The seed weevil deposits its eggs in the immature seed head and feed on and destroy the seed before they pupate. The stem weevil lays its eggs in the stems, branches and root crown. They were imported in the mid 1970’s and released in both Arizona and California. Surveys conducted in California indicated that puncturevine decreased by as much as 80% in the years after release. It appeared to be effective in Arizona as well but puncturevine started to build up about 10 years ago and has continued.  They both over winter as adults in plant material. Field borders and ditch banks are kept more weed free now than they were in the 60’s and 70’s and overwintering spots have declined. Part of the reason for the increase of puncturevine could be the reduction in overwintering sites. Weevils can be purchased but will be difficult to establish and maintain.

Area wide Insect Trapping Network   VegIPM Update, Vol. 14, No. 19, Sep 14, 2022
 
Results of pheromone and sticky trap catches can be viewed here.
 
Corn earworm:            
CEW moth counts beginning to increase, but a little below average for mid-September
 
Beet armyworm:         
Trap counts increased in most locations, bet well below average for mid- September.
 
Cabbage looper:         
Cabbage looper numbers remain low consistent with early September.
 
Diamondback moth:       
DBM moths starting to become active in some traps, about average for this time of the year.
 
Whitefly:                      
Adult movement increased in the past week, about below average for this time of year.
 
Thrips:                          
Thrips adults increased slightly in some locations (Tacna, Dome), and trending comparable to previous years.
 
Aphids:                        
Aphid movement is absent and consistent with what we typically see during September. 
 
Leafminers:                  
Adult activity up in a few locations (Yuma Valley), below average for mid-September.