John and I started our faculty careers just months apart more than three decades ago—he in vegetables and melons, me in cotton. We were forged in the same crucible: a time of intense agricultural crisis, stakeholder pressure, and institutional upheaval. We bore the same scars. That shared experience bound us in a special way, even as our day-to-day paths often diverged. Like the sun and moon, our seasons rarely overlapped—but when they did, we moved in rhythm, able to pick up conversations months later as if no time had passed. That was John: steady, grounded, always ready with insight, and always above the noise.

Over the years, we collaborated on critical efforts—most notably on resistance management for whiteflies, a challenge that demanded cross-commodity solutions. With John’s vision and leadership, we built voluntary stewardship agreements that are still in use a quarter-century later. More recently, we corresponded on a new tool to help growers manage resistance in real time—an app we’ll launch later this year. I had hoped he would be part of its rollout; his voice would have carried it far. Now, we will try to carry it forward in his spirit: practical, generous, and unwaveringly committed to growers.

This very newsletter—Vegetable IPM Updates—was John’s idea, and it thrived under his tireless dedication for decades. It was his way of connecting directly with those he served, every other Wednesday without fail. As we continue this tradition, we invite you to pause and reflect on how John and this newsletter may have touched your life or work. We honor him best by continuing to share the kind of clear, grounded, and useful information he believed in. We all know—that’s what John would have wanted.

-By Peter C. Ellsworth

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.

Botrytis rot is not considered a major problem in lettuce, but it can cause significant damage/loss when the field conditions are favorable for the pathogen. Cool wet conditions are favorable for the pathogen. Symptoms include water-soaked, brownish-gray to brownish-orange, soft wet rot that occurs on the oldest leaves in contact with the soil. Old leaves are more susceptible than young leaves and the fungus can move into the healthy parts. Fuzzy gray growth can be observed in the disease area which is characteristic of the pathogen. In worse cases, the entire plant can collapse. Romaine cultivars, transplanted lettuce that are big and have leaves touching the soil are more susceptible.

The pathogen: Botrytis cinerea
Botrytis cinerea affects most vegetable and fruit crops, as well as a large number of shrubs, trees, flowers, and weeds. Outdoors Botrytis overwinters in the soil as mycelium on plant debris, and as black, hard, flat or irregular sclerotia in the soil and plant debris, or mixed with seed. The fungus is spread by anything that moves soil or plant debris, or transports sclerotia. The fungus requires free moisture (wet surfaces) for germination, and cool 60 to 77 F, damp weather with little wind for optimal infection, growth, sporulation, and spore release. Botrytis is also active at low temperatures, and can cause problems on vegetables stored for weeks or months at temperatures ranging from 32 to 50. Infection rarely occurs at temperatures above 77 F. Once infection occurs, the fungus grows over a range of 32 to 96 F.

Masses of microscopic conidia (asexual spores) are produced on the surface of colonized tissues in tiny grape-like clusters (see picture). They are carried by humid air currents, splashing water, tools, and clothing, to healthy plants where they initiate new infections. Conidia usually do not penetrate living tissue directly, but rather infect through wounds, or by first colonizing dead tissues (old flower petals, dying foliage, etc.) then growing into the living parts of the plant.

Disease management:

1. Buy high-quality seed of recommended varieties. Treat the seed before planting.

2. Practice clean cultivation. Plant in a light, well-drained, well-prepared, fertile seedbed at the time recommended for your area. If feasible, sterilize the seedbed soil before planting, preferably with heat. Steam all soil used for plantbeds at 180 F (81 C) for 30 minutes or 160 F (71 C) for one hour.

3. Avoid heavy soils, heavy seeding, overcrowding, poor air circulation, planting too deep, over-fertilizing (especially with nitrogen), and wet mulches.

4. Focus on healthy plant vigor. Do not over fertilize.

5. Use drop or furrow irrigation instead of sprinklers. If sprinklers have to be used, irrigate morning or early afternoon giving enough time for foliage to dry.

6. Apply recommended fungicides when conditions favor disease development. Make sure to rotate fungicide to avoid development of resistance.

Save the date for the 6th annual downy mildew field day, information below!

It is with sadness and a sense of loss that we share the news that our friend and colleague, John Palumbo passed away last weekend. John and I have been office mates so to speak, only two doors apart, for the past 17 years. What I will miss most about John is his presence. Warren Buffet said that a key to becoming a better person was to surround yourself with people that are better than you. In other words, hangout with people who had traits and characteristics that you admire and want to emulate. John was one of those people. He made you want to be a better person. We will miss you, John. RIP.

Dr. John Palumbo never sought the spotlight, but everything he did—every trial, field visit, and conversation—pointed us toward something better: better science, better decisions, better farming.

I’ve looked up to John since my undergraduate days. He was the model of what I hoped to become: a scientist grounded in integrity, driven by purpose, and deeply connected to the people and land he served. A career-long dream came true when I asked him to join my Ph.D. committee—and he said yes. A defining moment in my journey that I’ll always carry with me.

The work we hoped to do with him is now a reminder of how much he still had to offer. But more than anything, I’m grateful. Grateful that I got to learn from him, talk with him, and be challenged by him. I especially loved when I’d share an idea and he would provide feedback like, “Now I don’t like the sound of that, and I’ll tell you why...” To me that meant he was listening closely. He cared. He was genuine.

John didn’t just give us answers—he gave us perspective and the confidence to ask better questions. His perspective came from a place of hard-earned wisdom which he shared humbly and freely. We’ve lost a giant, but his impact remains in our work, our conversations, and the values he quietly instilled. His presence is deeply missed—and deeply lasting.


-Macey Keith, Assistant in Extension

I had the privilege of knowing John for just over a year, yet his impact on my professional journey has been profound. To me, John was more than a colleague—he was a mentor. The knowledge I acquired from him will shape my career for years to come. His legacy was truly contagious and has inspired me to follow in his footsteps. John’s influence will continue to guide and motivate me throughout my life.

May God bless your soul, John. Rest in peace.

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.

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

 

Corn earworm: CEW moth counts down in most traps over the last 2 weeks; about average for early October

Beet armyworm: Moth Trap counts increased in several areas last week and appear to remain active in cooler temps, and well above average for early November.

Cabbage looper: Cabbage counts peaked last week in all locations, about average for this time of the season.

Diamondback moth: Adult activity declined in the past 2 weeks ago, Below average for this time of season.

Whitefly:  Adult movement continues with the termination of melon harvests; overall about average for early November.  

Thrips: Thrips adult movement still down, overall activity below average.

Aphids:Winged aphids movement peaked in the north Yuma and Gila Valleys; above average for early November.

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