For years, the blueberry industry has treated El Niño as an extraordinary event, responding with emergency measures only after high temperatures have already taken hold in the fields. However, the panel "Tools and strategies for mitigating the effects of the El Niño phenomenon"The speaker, who closed the International Seminar organized by Blueberries Consulting in Trujillo, concluded that the biggest challenge for the industry is not reacting to the climate event, but preparing plants capable of withstanding it.

The conversation brought together Jorge Retamales, Juan Hirzel, Walter Apaza Tapia, Jorge Castillo and Jessica Rodríguez, who, from the fields of plant physiology, nutrition, phytopathology, entomology and post-harvest, built an integrated view of the challenges that the Peruvian industry will face in a scenario where extreme weather events will become increasingly frequent.

Jorge Retamales, Juan Hirzel, Walter Apaza Tapia, Jorge Castillo, and Jessica Rodríguez. International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

Resilience begins at the roots

One of the panel's first points of consensus was that a plant's ability to cope with a stress event depends not only on genetics or climate, but also on the physiological state it is in at that moment.

Walter Apaza summarized this idea in a phrase that sparked the debate. "The more we enter the El Niño phenomenon with a good root system, the better equipped our plants will be to cope with those stressful conditions," he asserted.

According to the Peruvian specialist, this condition is not a matter of chance. It depends on soil or substrate management, fertigation, root development, and all those agronomic decisions made long before the first heat waves appear. "The soil is one thing, the substrate is another, and fertigation and management practices are something else entirely," he explained, emphasizing that the root system constitutes the first line of defense against climate stress.

Measure before you react

If the new climate scenario demands greater foresight, monitoring emerges as an indispensable tool. In this context, Juan Hirzel stated that technologies now exist capable of detecting physiological alterations early, allowing action to be taken before the plant shows visible symptoms.

"First, you need to have the instruments; second, know how to use them; and third, know what the normal ranges are for each variety," the researcher said, highlighting the usefulness of equipment for measuring gas exchange, leaf temperature, radiation, electrical conductivity, and water status, noting that all these variables allow us to understand how the plant actually responds to increased temperature.

But he went further and also made a direct appeal to genetically engineered companies.

"It is the responsibility of the genetic companies to characterize their varieties and provide that information to the producers," he warned, because in his opinion, the physiological knowledge of each variety will be as important as the genetics itself in the coming years.

Walter Apaza International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

Photosynthesis as the central element of the entire strategy

Rather than focusing on fertilization, Hirzel centered the discussion on protecting the plant's physiological functions. "The main physiological process that needs to be protected is the constant photosynthetic activity."

The renowned specialist explained that a plant that continues to photosynthesize maintains carbohydrate production, sustains fruit growth, synthesizes polyphenols, and preserves commercial quality. Conversely, when heat stress reduces photosynthesis, sugar production decreases, the synthesis of protective waxes is altered, and key attributes such as size and firmness begin to deteriorate. In this context, he called for a rethinking of traditional nutritional programs.

"Not all varieties need the same recipe," he stated, using a comparison that drew smiles from the audience.

"How many of you go to a restaurant and everyone orders the same dish?... well, we do that with plants."

For Hirzel, nutritional management must cease to be uniform and adapt to the physiology of each variety and each production system.

Juan Hirzel International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

The balance between photosynthesis and respiration

The physiological explanations were complemented by Jorge Retamales, who elaborated on one of the concepts developed during his keynote address. He reminded the audience that photosynthesis reaches its maximum efficiency around 20 to 25 °C, depending on the genetic material. Beyond that point, the situation changes.

"There may come a time when the amount of substrate that is respired begins to exceed what is formed through photosynthesis," he explained in the panel discussion.

When that happens, they indicated, the plant stops accumulating reserves and begins to consume them. The effect not only compromises the current season's production but also root development and the following season.

Retamales also noted that the plant has very clear physiological priorities.

"The first priority is the fruit; then come the shoots and the last priority are the roots," he explained. Therefore, excessive loads or prolonged periods of fruiting can limit root growth precisely when the plant most needs to strengthen its ability to adapt.

Jorge Retamales International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

Health begins before the pathogen

Another concept that permeated the entire conversation was that the health problem cannot be reduced solely to chemical control, and Walter Apaza emphasized that many diseases appear because the plant arrives weakened at the period of greatest stress. He also warned about the need to adapt marketing strategies to the actual condition of the fruit.

"Sometimes it's better to make the decision to go to a closer market than to send fruit to China and receive a complaint."

According to the researcher, the accelerated aging caused by the heat may make it unfeasible to ship certain varieties to long-distance destinations.

Along the same lines, Jorge Castillo advocated for a much more collaborative approach to plant health. "Plant health problems aren't confined to a small area; agriculture is practiced in open conditions," he commented.

The professor from the National Agrarian University La Molina maintained that sharing information among producers is as important as any chemical treatment. He also warned about the risk of relying exclusively on pesticides.

"Chemicals must be used, but we must know how to use them, because history is full of experiences where the overuse of pesticides ends up having a negative impact."

For Castillo, integrated management and communication among producers will be fundamental in the face of a climate scenario that will favor the emergence of new pests and diseases.

Jorge Castillo International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

La calidad también se construye después de la cosecha.

From a post-harvest perspective, Jessica Rodríguez noted that fruit is much more vulnerable when it has been subjected to high temperatures, which is why she emphasized that the time between harvesting and cooling will become increasingly crucial.

"The best tool we have to maintain the quality of the fruit is to cool it as quickly as possible."

The specialist recommended adjusting harvest times, even starting in the early morning when necessary, to reduce the pulp temperature before transport. She also called for a review of technologies currently used routinely.

At that point, Walter Apaza questioned the indiscriminate use of sulfur dioxide in areas where Botrytis It does not represent a significant risk.

"The fruit is asking for cold," he stated, recalling an old teaching shared by Retamales: "For every hour you delay cooling, it's one less day of post-harvest."

Jessica Rodríguez complemented that idea by pointing out that today there are diagnostic tools, such as molecular analyses using qPCR (a technique that simultaneously amplifies and measures DNA or RNA molecules), that allow for the objective determination of health risk before applying certain technologies.

Jessica Rodriguez International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

Prepare the plant before stress

The panel concluded with a question that summarized the entire conversation: Should nutrition correct deficiencies or physiologically prepare the plant before stress?

The responses were unanimous, and for Hirzel, nutrition should be geared towards building a functional plant, capable of sustaining photosynthesis, maintaining osmotic balance, and promoting the work of the root system.

Apaza agreed from a physiological perspective. Castillo noted that a malnourished plant will always be more susceptible to disease, and Saucedo added that a stressed plant is also more attractive to numerous pests due to the emission of volatile compounds that act as signals for insects.

Jessica Rodriguez and Jorge Castillo International Blueberries Seminar Trujillo 2026 © Blueberries Consulting

A new way of understanding resilience

Rather than offering solutions, the panel conveyed a key idea that resonated throughout the two days of the Trujillo Seminar: crop resilience doesn't depend on a single technology or a one-off application. It's built through the integration of physiology, nutrition, genetics, monitoring, phytosanitary measures, harvesting, and post-harvest handling. In other words, the El Niño phenomenon has ceased to be an exceptional event and has become a new, permanent management requirement.

The future competitiveness of the Peruvian blueberry industry will increasingly depend on its ability to understand this reality and translate scientific knowledge into timely decisions in the field. Because, as was made clear in this closing panel, the best strategy for facing the next El Niño begins long before the first high temperatures arrive.

Read also:

• Luis Miguel Vegas: Peru doubles blueberry production, but El Niño forces cautious projections
• “Understanding the plant to face climate change”, Jorge Retamales’ proposal for the new blueberry agriculture
• Genetics, health and climate adaptation marked the closing of the Trujillo 2026 International Blueberry Seminar
• Jessica Rodriguez: Reducing the time between harvesting and cooling will be key to protecting the firmness of blueberries
• Climate change, genetics and efficiency marked the first day of the International Blueberries Seminar Trujillo 2026
• Networking and innovation consolidate Trujillo as a meeting point for the blueberry industry