Hi, I’m Chris, and I’m thrilled to be stepping into the role of extension associate for plant pathology through The University of Arizona Cooperative Extension in Yuma County. I recently earned my Ph.D. in plant pathology from Purdue University in Indiana where my research focused on soybean seedling disease caused by Fusarium and Pythium. There, I discovered and characterized some of the first genetic resources available for improving innate host resistance and genetic control to two major pathogens causing this disease in soybean across the Midwest.

I was originally born and raised in Phoenix, so coming back to Arizona and getting the chance to apply my education while helping the community I was shaped by is a dream come true. I have a passion for plant disease research, especially when it comes to exploring how plant-pathogen interactions and genetics can be used to develop practical, empirically based disease control strategies. Let’s face it, fungicide resistance continues to emerge, yesterday’s resistant varieties grow more vulnerable every season, and the battle against plant pathogens in our fields is ongoing. But I firmly believe that when the enemy evolves, so can we.

To that end I am proud to be establishing my research program in Yuma where I will remain dedicated to improving the agricultural community’s disease management options and tackling crop health challenges. I am based out of the Yuma Agricultural Center and will continue to run the plant health diagnostic clinic located there. 

Please drop off or send disease samples for diagnosis to:
Yuma Plant Health Clinic
6425 W 8th Street
Yuma, AZ 85364

If you are shipping samples, please remember to include the USDA APHIS permit for moving plant samples.

You can contact me at:
Email: cdetranaltes@arizona.edu
Cell: 602-689-7328
Office: 928-782-5879

Vol. 12, Issue 4, Published 2/22/2021

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 “Advances in Weed Control Technologies” breakout session at the 2021 Southwest Ag Summit, university experts and cutting-edge innovators will provide updates on the latest developments in automated weeding, autonomous ag robots and non-chemical weed control. The first presenter will be Tony Koselka, COO and Vice President of Engineering, Vision Robotics Corp. Tony will be giving a history on the evolution of automated thinning/weeding technologies and real-world examples of how vision systems and artificial intelligence (AI) is being used with automated weeding machines today. Following Tony will be Paul Nagel, Chief Revenue Officer, Stout Industrial Technology, Inc. Paul will be discussing AI technologies available today, their capabilities, and where the technology is headed. Jaime Eltit, Head of Commercial Farming Operations, FarmWise, Inc. will be also be discussing AI technology and how machine learning is used for robotic in-row weed control. Additionally, he will be presenting information on the latest developments in autonomous weeding robots and their application in Arizona vegetable production systems. Finally, Dr. Steve Fennimore, Weed Scientist, UC Davis will be presenting information on a novel technique for using steam heat to control sclerotinia lettuce drop, Fusarium wilt of lettuce and in-row weeds in vegetable crops.

The session will be held TOMMOROW Thursday, February 25^th from 1:30-3:30. If you are unable to attend the live session, recordings of the presentations will be available on March 2 and March 3. For those interested in CEU’s, the session offers 2 AZ/CA PCA and CCA credits. One last thing, you must be registered for the 2021 Southwest Ag Summit in order to attend the session. To register or for more information about the Southwest Ag Summit, visit https://yumafreshveg.com/southwest-ag-summit/. Hope to see you there for what promises to be an enlightening and informative session.

Heavy and widespread infestations of common purslane come up during ground preparation for lettuce every year. This occurs in fields that were kept weed free the previous year and is difficult to understand.

There are probably several reasons for this.

Seed Production
Common Purslane is very prolific. It has been reported that one plant can produce up to 240,000 seeds. The stems are so succulent that plants can remain viable and make seed even after it is uprooted.

Seed Longevity
Once seed is mature it can be viable for as long as 40 years. It has very small, hard seed that can remain dormant in the soil for ss long as 40 years .So you may have to control weeds that got into the field a generation ago..

Multiple perennial germinations
Common Purslane is supposed to be a summer annual, but it germinates multiple times all year in the low desert. It takes 12 hours after receiving moisture in the summer and 7 days in the winter, but it keeps germinating. It has to be controlled when it is less than 2” in diameter. If you wait until most of it germinates the early plants will be too big. If you spray or cultivate when all the emerged plants are small you will miss many that have yet to emerge.  It is best to treat early and control the later emerging plants with a selective herbicide.

Rerooting
When common purslane is broken in pieces it can reroot at the nodes. Late cultivation often spreads this weed. Cultivation is not a good option when purslane is larger than 2”. Herbicides are a better option on big plants.

Seed dispersal
Purslane has a very small light seed. It moves in irrigation water and blows in the wind. Even completely clean fields are likely is be reinfested by seeds that are carried by water and wind into the field.

Best option
Considering the above factors, the best option for controlling common purslane may be preirrigation to germinate the weeds and early herbicide application  or cultivation . Kerb and Prefar are both good on purslane. Prefar should be used at planting to incorporate it with a lot of water and Kerb should be used later to avoid leaching but don’t wait too long and risk germination of the weeds. Purslane germinates from shallow depths and split applications of Kerb may be a good option.

This time of year, John would often highlight Lepidopteran pests in the field and remind us of the importance of rotating insecticide modes of action. With worm pressure present in local crops, it’s a good time to revisit resistance management practices and ensure we’re protecting the effectiveness of these tools for seasons to come. For detailed guidelines, see Insecticide Resistance Management for Beet Armyworm, Cabbage Looper, and Diamondback Moth in Desert Produce Crops .

VegIPM Update Vol. 16, Num. 20

Oct. 1, 2025

Results of pheromone and sticky trap catches below!!

Corn earworm:  CEW moth counts declined across all traps from last collection; average for this time of year.

Beet armyworm: BAW moth increased over the last two weeks; below average for this early produce season.

Cabbage looper: Cabbage looper counts increased in the last two collections; below average for mid-late September.

Diamondback moth: a few DBM moths were caught in the traps; consistent with previous years.

Whitefly:  Adult movement decreased in most locations over the last two weeks, about average for this time of year.

Thrips: Thrips adult activity increased over the last two collections, typical for late September.

Aphids: Aphid movement absent so far; anticipate activity to pick up when winds begin blowing from N-NW.

Leafminers: Adult activity increased over the last two weeks, about average for this time of year.