Early Sunday morning, 11 May 2025 Dr. John Palumbo passed away at his home in Yuma, AZ. John was an excellent scientist and educator, a lifelong student who truly enjoyed good work and a full life. John was also a very good friend and colleague, not only to me but to the many with whom he worked and lived. We mourn his passing and miss him deeply.
I first met John in 1990 when he joined the faculty at the University of Arizona (UA) as an Assistant Professor and Extension Specialist in Entomology and Integrated Pest Management (IPM) based at the Yuma Agricultural Center (YAC). He came very highly recommended by Drs. Theo Watson and Leon Moore, who were research and Extension entomologists and former mentors of John’s when he was an undergraduate and graduate student at the UA.
John did his Ph.D. work at Oklahoma State University (OSU) under the direction of Dr. Larry Crowder, who had been on the UA faculty in entomology prior to moving to OSU. I am originally from Oklahoma and went to graduate school at OSU in agronomy and soil science. I used to jokingly tell John that having spent some formative years in Oklahoma was probably his time of refinement and saving grace.
John was a perfect fit for the position at the UA and at YAC; he was highly intelligent with an excellent background. Most importantly, it was very clear that he was enthusiastic about his opportunity, and he really wanted to do the work necessary. He truly loved his work, and he did it very well with passion and commitment.
John had an outstanding work ethic, he was a man of good character, and his integrity was exceptional. John was a practical realist, and even though we could both see and comment on the imperfections in the world around us, he did not whine or complain about things that could have been better. He was always an optimist, and he did the best with what he had, appreciated his opportunities, and he consistently did a great job with it. He was a model as a professional and as a good person. He had confidence in himself, but he was humble, and he always treated people with respect and dignity. Very importantly, John had a great sense of humor, and I could always count on that with him.
In 2018 John was diagnosed with stage 4 lung cancer. That was not a good prognosis, but John faced it with dignity and grace. John had access to some new drugs that helped give him a good quality of life that he sustained for seven years. In the past seven years he has been productive, worked hard, and he has had fun doing so. He did not dwell on the negative but always emphasized the positive.
John was an avid reader and we both shared an interest in history, particularly American history, including the Civil War. Many of our conversations centered around these common interests and we shared many good reading references.
In my readings I have also enjoyed the writings of Ernest Hemingway. Hemingway emphasized the value and benefits of living a robust life and spending time outdoors in nature. Many of his characters demonstrated a strong way of living and strength in facing the end of their lives. In one of Hemingway’s books (Across the River and Into the Trees) he offered a recounting of the passing of General Thomas “Stonewall” Jackson on 10 May 1863 following his injuries at the Battle of Chancellorsville.
Dr. McGuire, the attending physician, confirmed to Jackson what his wife had conveyed earlier regarding McGuire’s projection of his impending death that day. Jackson’s response after thinking for a moment was that the day was Sunday and he felt that Sunday was a good day to die. After passing in and out of delirium, the last he said was “Let us cross the river and rest in the shade of the trees.”
John Palumbo passed away on a Sunday in May. He has crossed the river and is now resting in the shade of the trees.
I hope you are frolicking in the fields of wildflowers picking the prettiest bugs.
I was scheduled to interview for plant pathologist position at Yuma on October 18, 2019. Few weeks before that date, I emailed Dr. Palumbo asking about the agriculture system in Yuma and what will be expected of me. He sent me every information that one can think of, which at the time I thought oh how nice!
When I started the position here and saw how much he does and how much busy he stays, I was eternally grateful of the time he took to provide me all the information, especially to someone he did not know at all.
Fast forward to first month at my job someone told me that the community wants me to be the Palumbo of Plant Pathology and I remember thinking what a big thing to ask..
He was my next-door mentor, and I would stop by with questions all the time especially after passing of my predecessor Dr. Matheron. Dr. Palumbo was always there to answer any question, gave me that little boost I needed, a little courage to write that email I needed to write, a rigid answer to stand my ground if needed. And not to mention the plant diagnosis. When the submitted samples did not look like a pathogen, taking samples to his office where he would look for insects with his little handheld lenses was one of my favorite times.
I also got to work with him in couple of projects, and he would tell me “call me John”. Uhh no, that was never going to happen.. until my last interaction with him, I would fluster when I talked to him, I would get nervous to have one of my idols listening to ME? Most times, I would forget what I was going to ask but at the same time be incredibly flabbergasted by the fact that I get to work next to this legend of a man, and get his opinions about pest management. Though I really did not like giving talks after him, as honestly, I would have nothing to offer after he has talked. Every time he waved at me in a meeting, I would blush and keep smiling for minutes, and I always knew I will forever be a fangirl..
Until we meet again.
PBS News recently did a story on the importance of Yuma’s winter vegetable production and the pressures the Western US is facing due to water scarcity. The story features insights from local growers Matt McGuire, JV Smith Companies and Jon Dinsmore, Dinsmore Farms, as well as Arizona Department of Agriculture Director, Paul Brierley. The report is well done, covering the basics of Yuma agriculture and the water shortage issues the industry is facing. It’s a quality piece, worth a listen.
Check it out by clicking here or on the image below.
Fig. 1. PBS NewsHour: “Arizona Farmers Forced to Adapt as Main Water Source Dries Up” story. (Photo Credits: PBS News)
Wanted to share the following weed germination calendars now that the season has begun. Some summer weeds withstand part of the winter and some winter annuals the summer, so these charts are general guidelines. We hope this helps for making management decisions in your operation.
Aphids are considered the most difficult to control insect pests in organic vegetables due to the lack of effective bioinsecticides as well as their ability to hide within plant structures. For instance, lettuce aphids normally hide in the head or heart of lettuce, making them difficult to reach by insecticide treatment or natural enemies. It is important to adopt other methods, such as nitrogen and water management, for additional aphid suppression.
As sap-sucking insects, aphids depend on the nutritional content of the sap ingested from the plant hosts for proper growth and development. Nitrogen availability is one of the most important factors in the development of aphid populations. Thus, limiting your nitrogen application to the optimum amount required for your crops is good practice for maintaining your aphid population below damaging level. Additionally, the use of slow-release (minimizing the risk of nutrient deficiency or excess) nitrogen fertilizer can be beneficial for aphid control. On the other hand, excess of nitrogen will make your crops a superfood for aphids. This accelerates the growth, development, and reproduction of the pests, reduces their generation time, and results in an increase in the number of generations and density during the cropping season. Excess of nitrogen particularly affects aphids on host crops such as lettuce, wheat, and sorghum. In some situations, high nitrogen levels in plant tissue can decrease resistance and increase susceptibility to aphids’ attacks. Applying the optimum amount of nitrogen fertilizer can tremendously help to manage aphids. In addition to pest management, effective fertilizer usage can also result in economic and environmental benefits.
Selected References:
1- Altieri, M. A., C. I. Nicholls, and M. A. Fritz. Manage insects on your farm: a guide to ecology strategies. SARE. https://www.sare.org/resources/manage-insects-on-your-farm/
2- Aqueel, M. A., and S. R. Leather. 2011. Effect of nitrogen fertilizer on the growth and survival of Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Homoptera: Aphididae) on different wheat cultivars. Crop Protection. 30:216-221.
3- Bal, R., M. Groshok, and Y. Jama. 2024. Effects of nitrogen and potassium-based fertilizers on green peach aphid and abundance and arugula condition and growth. The Scientist. 6:1. https://journals.mcmaster.ca/iScientist/article/view/2931
4- Sinha, R., B. Singh, P. K. Rai, A. Kumar, S. Jamwal, and B. K. Sinha. 2018. Soil fertility management and its impact on mustard aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae). Cogent Food & Agriculture. 4: 145094.
5- Xia, C., W. Xue, Z. Li, J. Shi, G. Yu, and Y. Zhang. 2023. Presenting the Secrets: exploring endogenous defense mechanisms in chrysanthemums against aphids. Horticulturae. 9: 937. https://doi.org/10.3390/horticulturae9080937
Supplying the optimum amount of water to your crop is also very important for effective pest control. Water availability around plant roots increases nitrogen absorption. Additionally, with high water availability, there is an increase in phloem pressure, making food more accessible to sap-sucking insect pests. Supplying the required amount of water using appropriate irrigation methods and irrigation scheduling can be beneficial for pest management. Although these practices will not completely prevent infestation of aphids, they can surely play a role in reducing the density of aphid populations on your crops.I had the privilege of knowing Dr. John Palumbo for nearly a year, and in that short time, he left a lasting impact on me both personally and professionally. From the moment I joined the Yuma Agricultural Center, John welcomed me with genuine generosity, readily offering his help and connecting me with key stakeholders in the Yuma area. Despite the demands of his extensive and impactful program, his office door was always open for any questions I had. Just a few weeks ago, I was attending a workshop in Imperial, California, hosted by the University of California Cooperative Extension. During the IPM session, I believe his name was mentioned more than ten times, underscoring the depth and influence of his research, findings, and recommendations. John was a true leader of the agricultural community in the Southwest, and his contributions will continue to shape the field for years to come. He leaves behind a legacy of excellence, mentorship, and service. Thank you, Dr. John Palumbo, for everything you have done. You will be deeply missed and fondly remembered.
