This week I presented a poster at the Entomological Society of America’s (ESA) 2025 Annual Meeting in Portland, Oregon, sharing the impacts of Arizona Pest Management Center (APMC) with a diverse audience representing part of the ESA’s nearly 7,000 members nationwide. It was rewarding to share how our real-world IPM efforts in the desert Southwest influence field decisions, grower profitability, and environmental health.

Attendees from other entomological disciplines were surprised by the measurable progress our Arizona vegetable and cotton IPM programs have achieved, flipping the script from risk to safety in how we tell the story of pest management. It was a great reminder of how powerful IPM can be when guided by science and collaboration.

You can find the poster here: Arizona Pest Management Center: Advancing Integrated Pest Management (IPM) for Agriculture and Communities

At the APMC, our approach to resistance management starts with prevention by avoiding resistance before it ever appears. That means rotating modes of action and skipping unnecessary sprays to protect what still works. If you want to learn more (or want a good chuckle) watch our short Proactive Resistance Management App commercial to see how easy proactive can be. Click below to watch the commercial.


To contact Macey Keith go to: maceyw@arizona.edu

In 2023 Arizona and the lower basin states were operating under Tier 2 reductions, consistent with the Drought Contingency Plans (DCP) for Colorado River conservation in response to the drought conditions (Figure 1).  Tier 2 conditions imposed a 592,000 acre-feet (kaf) reduction in Arizona’s 2.8 million acre-feet (maf) total allocation from the Colorado River.  These reductions have primarily impacted the irrigation districts in central Arizona.
 
For 2024, the Bureaus of Reclamation (BoR) has announced in August 2023 that the river operations will follow Tier 1 DCP reductions (Figure 1).  That is due to an increase in the water levels in Lake Mead in the past year with an excellent snowpack last winter and above average runoff in 2023.  That increase in water level at Hoover Dam in Lake Mead is primarily a function of an excellent snowpack and higher rainfall in the Colorado River basin in 2023.  Significant conservation efforts have been employed as well.

Figure 1.  2024 Tier 1 Shortage for the Colorado River operations.  Source:
Arizona Department of Water Resources.

With agriculture responsible for 70% of the diversions on the Colorado River, tracking the snowpack is an important exercise for forecasting and managing the precious water resources in this region and this watershed for sure.
 
The pressures on the Colorado River system because of the drought that has been impacting the entire basin and region for 23 years have slackened briefly due to the wet winter in 2023 with a good snowpack in the mountains, good rainfall throughout the basin, good flows into the river, and conservation.  
 
The current water level at Lake Mead on Hoover Dam is 1,068.25 ft. above sea level on 3 January 2024.  That level is 160.75 ft below full pool of 1,229.00 ft. (Figure 2).

Figure 2.  Lake Mead water height (feet above sea level at Hoover Dam) history
and critical Tier conditions.  Source: U.S. Bureau of Reclamation.

The current snowpack in the Colorado River Basin is at 74% of average and below levels of this time last year.  However, hydrological records indicate that most of the snowpack in this basin accumulates between February and April.  
 
So, it is worth watching the snowpack accumulation and it is always good to pray for more snow in mountains to the north for those of us working and living in this desert with a heavy dependence on this water.  However, while monitoring the snowpack gives us a capacity to project, none of that really counts until there is water in the river and in the reservoirs, like money in the bank.

 

Mark C. Siemens, Department of Biosystems Engineering
Vol. 14, Issue 16, Published 8/9/2023
Pre-Season Vegetable IPM Workshop
Mark C. Siemens
Vol. 14, Issue 17, Published 8/23/2023

The Pre-Season Vegetable IPM Workshop will be taking place TOMORROW, Wednesday, August 23^rd at the Yuma Agricultural Center. Come learn about the latest IPM products, practices and trial results from university and industry experts. Registration begins at 7:30 am and the program starts at 8:00 am. Agenda below. Looking forward to seeing everyone there!

 

We have a large amount of summer grasses emerging right now in the desert. Identification is very important. Knowing the field history is helpful to plan your preemergence herbicide applications.
There is a tendency to group summer grasses together and called them all watergrass, or barnyard grass especially because they are so difficult to identify at early growth stages. 
Some of these grasses respond differently to herbicides. For example, sprangletop is only controlled by the high rates of Select (clethodim) and clethodim generics and missed by other postemergence herbicides such as Post (sethoxydim) and Fusilade (fluazifop).
Others like Field Sandbur (Cenchrus pauciflorus) and Sandbur (Cenchrus echinatus) are tolerant to these herbicides which don’t achieve acceptable control.
From the more than 25 annual grass species found in our area during the summer I listed in 13 commonly found below that are in the Section VI of the PCA study guide.
Also, the following is a link Summer Annual Grass Identification to a publication by Barry Tickes with images and description of the 6 genera and 12 species of summer annual grasses that are common here.
 
Summer Annual Grasses

Barnyardgrass	Echinochloa crus-galli
Red sprangletop	Leptochloa filormus
Prairie Cupgrass	Eriochloa contracta
Field sandbur	Cenchrus spinifex
Yellow foxtail	Setaria glauca
Feather fingergrass	Chloris virgata
Crowfootgrass	Dactyloctenium aegyptium
Junglerice (Watergrass)	Echinochloa colona
Mexican sprangletop	Leptochloa fusca
Southwestern Cupgrass	Eriochloa acuminata
Southern sandbur	Cenchrus echinatus
Green foxtail	Setaria viridis
Sixweeks grama	Bouteloua barbata

 

 

 

Figure 1. Left southern sandbur and right field sandbur

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

 

Corn earworm: CEW moth beginning to incresase in some areas, particularly in Wellton and Tacna in the past week; Above average for this time of season.

Beet armyworm: Moth trap counts increased in most areas, above average for this time of the year.

Cabbage looper: Moths continue to increase in all traps in the past 2 weeks, and average for this time of the season.

Diamondback moth: Adults remain the same, but very active in in Wellton and the N. Yuma Valley.  Overall, average for February.

Whitefly: Adult movement remains low in all areas, consistent with previous years.

Thrips: Thrips adults movement increase slightly in past 2 weeks, most notably in Roll. Overall activity average for February.

Aphids:  Winged aphids are still actively moving and reached seasonal highs in the past two weeks.  Well above average for February.

Leafminers: Adult activity down in most locations, below average for this time of season.