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.
For those interested in in-row weed control, checkout the quality video below (Fig. 1) on how finger weeders (Fig. 2) are being used on a 3,600 acre organic cotton farm in Texas. The grower states that finger weeders help him achieve 95-97% weed control and are a highly cost-effective tool for lowering hand weeding costs.
Fig. 1. Carl Pepper discusses how finger weeders are used to control in-row weeds on
his 3,600 acre organic cotton farm. Click here or on image to view. (Photo credit: Tilmor
LLC, Dalton, OH)
Fig. 2. Finger weeders, an in-row weeding tool, operating in seedling cotton. Finger
weeder pairs are centered on the seed row and overlapped slightly to loosen soil in the
row and uproot small weeds.
In our last update we invited you to come to the YAC to look at a broccoli trial we have in which we sprayed Trifluralin at 1.5 pt/ acre preemergence (PREE) incorporated mechanically. The application was made to the flat ground then incorporated with a disk at 4”depth. Then rows were built, and broccoli was direct seeded and germinated with sprinkler irrigation. Last year we saw injury in a non-disked Treflan treatment, so I didn’t include it in the trial. The same procedure was done with Prowl at 1pt with disked and non-disked plots.
Additional PREE treatments were Devrinol at 1pt/a, Prefar6qt/a, Goal tender at high rate of 16floz/a.
Prowl mechanically incorporated looks better than Non-incorporated in weed control as well as not showing phytotoxicity symptoms. Treflan, also mechanically incorporated looks similar to Prowl with a very small number of large weeds. The predominant weeds in this field are goosefoot and lambs quarter and are showing restricted growth not being as competitive with the broccoli.
Our observations in the trial as well as your field experience shows us with Treflan and Prowl available PREE and the post emergence herbicides such as Clethodim and Goal the absence of Cacthal can be mitigated to some degree. Again, you are welcome to come look at it at the Yuma Ag Center.
Treatments didn’t affect broccoli stand except Goal high rate PREE as expected.
Prowl and Treflan applied on the flat and incorporated mechanically did not produced phytotoxicity symptoms at 13 and 28 days after planting.
All weeds were about 0.5” at the time of this evaluation.
Some of the small weeds observed in the 13-day evaluation in the disked Prowl and Treflan died or didn’t grow by day 28.
Biological control is an important IPM tool globally. This pest suppression technique is especially important for managing pests in organic crop production. There are various biological control techniques, including conservation biological control, classical biological control, and augmentative biological control. Conservation biological control is the practice of providing habitat to support abundant populations of naturally occurring arthropods that attack crop pests. However, classical biological control and augmentative biological control involve the release of arthropod predators and parasitoids, usually non-native, into the field or greenhouses. This article focuses on conservation biological control.
The contribution of native beneficial insects to pest control has been estimated to be approximately $4.5 billion annually in the United States alone. However, the benefits of beneficial insects areoften overlooked. Research conducted across the country has shown evidence that conserving natural habitats leads to an increase in beneficial arthropod populations and a reduction in pest problems on farms. Beneficial arthropod predators and parasitoids often rely on natural or semi-natural areas adjacent to the field for their persistence. Between growing seasons, these natural and semi-natural areas provide alternative food sources, overwintering, and nesting habitats for natural enemies, thereby promoting their populations. To complete their life cycle, natural enemies require more than just prey or hosts; they also need refuge sites and alternative food sources.
Neighboring natural and semi-natural habitats serve as sources of natural enemies during the growing seasons to suppress crop pests. The establishment of wildflower margins around crop fields increases the abundance of beneficial insects that search for pollen and nectar. For example, many adult parasitoids sustain themselves with pollen and nectar from nearby flowering plants while searching for hosts. Most natural enemies do not disperse far from their overwintering sites; access to permanent habitat near or within the field gives them a jump-start on early pest populations.
Farms with diverse and dense populations of natural enemies are likely to exhibit the following characteristics:
- Have small fields surrounded by natural vegetation.
- Composed of diversified cropping systems and plant populations in or around fields include perennials and flowering plants.
- Crops are managed organically or with minimal agrichemicals.
- Soils are high in organic matter and biological activity and, during the off-season, covered with mulch or vegetation.
Figure 1. Syrphid fly feeding from sweet alyssum flowers.
Figure 2. Mix flowers planted on strips between rows of celery to provide food and
shelter for natural enemies.
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.
