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Different ways to learn November 21st, 2021 by

Vea la versión en español a continuación

In June I wrote a story about a virtual meeting with some farmers in Iquicachi, on the shores of Lake Titicaca (Zoom to Titicaca), where they discussed how to manage what was (for them) a new pest: the potato tuber moth. Later, several people wrote to me to say that they hoped these farmers could solve their problem. So I’m writing an update.

I went to Lake Titicaca on 16 November to meet the farmers in person, and they’re doing well.

The agronomists they work with taught them to use ground chalk from a building supply shop to coat the seed potatoes. The chalk discourages the tiny larva of the moth from burrowing into the potato. This and some other techniques are helping to keep the tuber moth down.

At our recent meeting, I was impressed (as I often am) how scientists and farmers have different ways of seeing the world. There’s nothing mystical about his. It’s because they use different methods of observation.

An entomologist sees an insect by killing some specimens and looking at them under the microscope. It is an excellent way to see the details of nature that cannot be readily seen with the naked eye. For example, one of the three species of tuber moths has triangular markings on its wings.

But the farmers of Titicaca were less interested in comparing each species of moth, and more intent on comparing them to another pest, one they have had for ages: the Andean potato weevil.

These Yapuchiris (expert farmers) and their neighbors noticed that the moths’ larvae are much smaller than the worms that hatch from weevil eggs. Second, the weevil only eats a part of the tuber, while the larvae of the moth “have no respect for the potato” and destroy the whole thing. Third, the weevil can’t fly, but the moth “flies in jumps” (it takes short flights).

In all fairness, entomologists have also noticed these behaviors, and the Yapuchiris have recently observed that one species of moth is darker than the other. But the farmers emphasize behavior more, and have their own rhetoric for discussing it (e.g. as jumping). Note that this is not ancestral knowledge, because this pest is new on the Altiplano. These Yapuchiris only noticed the moth 10 years ago, and they have been observing it since then. The farmers learn about insects while farming and processing food. They watch while they work. They don’t set up lab experiments.

The Yapuchiris have strengthened their observations by interacting with agronomists. In this case the extensionists explained that the moths are the adults of the worms, so the farmers then began to pay more attention to the moths.

These improved observations have paid off.

While I was in Iquicachi, one of the Yapuchiris, Martín Condori, suggested that since the tuber moth does not fly very far, it could be kept out of potatoes by planting a row of broad beans or lupin beans between every three rows of potatoes. It’s a new idea, that only occurred to don Martín while we were meeting.

His fellow Yapuchiri, Paulino Pari, immediately warmed to don Martín’s suggestion for an intercropping experiment. Don Paulino said that a row of lupin beans might help to stop the moth from spreading into the potatoes, because the lupin plants are toxic to the moths.

This is the value of farmer-scientist collaboration. The farmers learn that the worms in their potatoes have hatched from the eggs laid by moths. Farmers then pay more attention to the moths, and create new ideas for keeping the moths out of the potato field.

Intercropping may or may not help to manage the moth, but it is an idea that farmers and agronomists can try together.

Years ago in Honduras, Keith Andrews, an entomologist, first told me that farmers identify insects more by their behavior and ecology than by their morphology. I’ve spent many years noticing that he was right.

Acknowledgements

A special thanks to Ing. Roly Cota, who works at PROSUCO, for taking me to Iquicachi and introducing me to the Yapuchiris, so we could validate three new fact sheets for farmers on the potato tuber moth. Our work was supported by the  Collaborative Crop Research Program (CCRP) of the McKnight Foundation.

Photo credit

Photo courtesy of Roly Cota.

Further reading

There is some excellent research on the potato tuber moth. For example, see this paper and references cited.

Olivier Dangles, Mario Herrera, Charlotte Mazoyer and Jean-François Silvain 2013 Temperature-dependent shifts in herbivore performance and interactions drive nonlinear changes in crop damages. Global Change Biology 19, 1056–1063, doi: 10.1111/gcb.12104.

Scientific names

There are two native tuber moths in Bolivia: Symmetrischema tangolias, and Phthorimaea operculella. There is also a Guatemalan tuber moth, Tecia solanivora, but it has not been reported in Bolivia. All three of these moths belong to the Gelechiidae family. They are about a centimeter long, about as long as your smallest fingernail. Many Gelechiidae attack stored cereal products, and so you may have been alarmed to find them in your cupboard.

Video on the fascinating lupin bean

Growing lupin without disease

APRENDIENDO CON OTROS OJOS

Por Jeff Bentley, 21 de noviembre del 2021

En junio escribí un relato sobre una reunión virtual con los agricultores de Iquicachi, a orillas del lago Titicaca (Zoom al Titicaca), en la que se discutía cómo gestionar lo que era (para ellos) una nueva plaga: la polilla de la papa. Más tarde, varias personas me escribieron para decirme que esperaban que estos agricultores pudieran resolver su problema. Así que escribo una actualización.

El 16 de noviembre fui al Lago Titicaca para conocer a los agricultores en persona, y están bien.

Los agrónomos con los que trabajan les enseñaron a usar tiza molida de una tienda de materiales de construcción para recubrir la papa semilla. La tiza no deja que la pequeña larva de la polilla penetre a la papa. Esta y otras técnicas están ayudando a reducir la polilla de la papa.

En esta última reunión, me impresionó (como en muchas veces) cómo los científicos y los agricultores tienen formas diferentes de ver el mundo. No tiene nada de místico. Es porque usan distinto métodos de observación.

Un entomólogo observa un insecto al matar algunos ejemplares y mirándolos al microscopio. Es una forma excelente de ver los detalles que no se pueden ver fácilmente a simple vista. Por ejemplo, una de las tres especies de polillas de la papa tiene marcas triangulares en las alas.

Pero los campesinos del Titicaca estaban menos interesados en comparar cada especie de polilla, y más en compararlas con otra plaga, una que tienen desde hace mucho tiempo: el gorgojo de los Andes.

Estos Yapuchiris (agricultores expertos) y sus vecinos se dieron cuenta de que las larvas de las polillas son mucho más pequeñas que los gusanos que nacen de los huevos del gorgojo. En segundo lugar, el gorgojo sólo se come una parte del tubérculo, mientras que las larvas de la polilla “no respetan la papa” y la destruyen completamente. En tercer lugar, el gorgojo no puede volar, pero la polilla “vuela a saltos” (have vuelos cortos).

En realidad, los entomólogos también se han dado cuenta de estos comportamientos, y los Yapuchiris han observado recientemente que una especie de polilla es más oscura que la otra. Pero los campesinos enfatizan más el comportamiento, y tienen su propia retórica para discutirlo (los saltos, por ejemplo). Fíjese que no se trata de un conocimiento ancestral, porque esta plaga es nueva en el Altiplano. Estos Yapuchiris sólo se dieron cuenta de la polilla hace 10 años, y desde entonces la observan. Los campesinos aprenden sobre los insectos mientras cultivan y procesan los alimentos. Observan mientras trabajan. No hacen experimentos de laboratorio.

Los Yapuchiris han reforzado sus observaciones interactuando con los agrónomos. En este caso, los extensionistas les explicaron que las polillas son los adultos de los gusanos, por lo que los agricultores comenzaron a prestar más atención a las polillas.

Estas observaciones mejoradas han dado sus frutos.

Durante mi visita a Iquicachi, uno de los Yapuchiris, Martín Condori, sugirió que, como la polilla de la papa no vuela muy lejos, se podría sembrar un surco de tarwi (lupino) entre cada tres surcos de papa, para que no entre la polilla. Es una idea nueva, que sólo se le ocurrió a don Martín mientras nos reuníamos.

Otro Yapuchiri, don Paulino Pari, aceptó inmediatamente la sugerencia de don Martín de hacer un experimento de cultivo intercalado. Don Paulino dijo que un surco de tarwi podría ser una barrera para la polilla, porque las plantas de tarwi son tóxicas para las polillas.

Este es el valor de la colaboración entre agricultores y científicos. Los agricultores se enteran de que los gusanos de sus papas han nacido de los huevos puestos por las polillas. Los agricultores prestan entonces más atención a las polillas y crean nuevas ideas para mantener las polillas fuera del campo de papas.

Los cultivos intercalados pueden ayudar o no a controlar la polilla, pero es una idea que los agricultores y los agrónomos pueden probar juntos.

Hace años, en Honduras, Keith Andrews, un entomólogo, me explicó por primera vez que los agricultores identifican a los insectos más por su comportamiento y ecología que por su morfología. Llevo muchos años comprobando que tenía razón.

Agradecimientos

Muchas gracias al Ing. Roly Cota, quien trabaja en PROSUCO, por llevarme a Iquicachi y convocar una reunión con los Yapuchiris, donde pudimos validad tres nuevas hojas volantes para agricultores sobre la polilla de la papa. Nuestro trabajo ha sido auspiciado por el Programa Colaborativo de Investigación sobre Cultivos (CCRP) de la Fundación McKnight.

Foto

Foto cortesía de Roly Cota.

Lectura adicional

Hay varios excelentes trabajos de investigación sobre la polilla de la papa. Por ejemplo, vea este artículo y los otros en las referencias citadas.

Olivier Dangles, Mario Herrera, Charlotte Mazoyer and Jean-François Silvain 2013 Temperature-dependent shifts in herbivore performance and interactions drive nonlinear changes in crop damages. Global Change Biology 19, 1056–1063, doi: 10.1111/gcb.12104.

Nombres científicos

Hay dos polillas de la papa nativas en Bolivia: Symmetrischema tangolias, y Phthorimaea operculella. Además, hay una polilla guatemalteca de la papa, Tecia solanivora, pero no ha sido reportada en Bolivia. Las tres polillas pertenecen a la familia Gelechiidae. Miden más o menos un centímetro, más o menos lo largo de su uña meñique. Muchos Gelechiidae atacan cereales almacenados, y es posible que le hayan sorprendido en su dispensa.

Video sobre el fascinante tarwi

Producir tarwi sin enfermedad

El mismo video, en el idioma aymara

Eating the experiment July 25th, 2021 by

Vea la versión en español a continuación

Even though farmers and agricultural scientists share the same field of study, they have completely different experimental styles.

This past year in Ecuador, Ph.D. candidate Israel Navarrete was encouraging farmers to experiment, and he was struck by how much time it took them just to pick a research question. While organizing three small groups of farmers in the province of Cotopaxi, Israel found that the local people could take up to three meetings just to pick a topic. Some farmers felt that the other group members weren’t listening to them. (Hurt feelings are as normal in peasant communities as in university departments).

One of Israel’s small groups, made up entirely of women, was dedicated to growing potatoes and black maize. Like the farmers I wrote about recently from Lake Titicaca, the Ecuadorian women had problems with tuber moths destroying their seed potatoes. These farmers from Cotopaxi eventually decided to see if they could control the moths by treating their seed potatoes with garlic extract and with “cementina” (a local type of construction lime).

Israel encouraged them to do multiple replicates of the experiment. Replicates (simultaneous repetitions of the experiment) are a hallmark of the scientific method, and they are especially important in agriculture where each plot of earth, each batch of seed is slightly unique, like snowflakes. An idea has to be tried several times to see if the result is consistent, and is not just a chance occurrence.

But the farmers of Cotopaxi declined to use replicates, and simply tried the lime and garlic on one batch of seed. The solution seemed to work, so Israel encouraged the women to try it again, perhaps in different treatments (such as the lime alone, or the garlic alone, and both together). But the farmers refused. They were satisfied with the results.

As Israel explained this experience, he tried to hide his frustration that the farmers would not work on the experiment in more detail. He was philosophical about the results. He said, “The farmers take a complicated idea and test it in a simple way, while researchers take a simple idea, and test it in a complicated way.”

Much of the scientific method is designed to show universal truth. The experiment has to be replicable and described in numbers and published. After the data is collected, the experiment can be thrown away.

For the farmers, the experiment doesn’t have to be replicable. It only has to achieve results on their farm. It doesn’t need numbers because the farmers are looking for large qualitative differences. You either get rid of the tuber moths, or you don’t. And unlike the scientists, the farmers have to make a living from the actual experiment. In this case, the farmers planted the seed potatoes they had dusted with lime and garlic.

The scientists write up the experiment and publish. It is part of their job. The farmers learn from the experiment and then eat it. It is part of their life.

In spite of having remarkably different experimental styles, collaboration between smallholders and researchers is most valuable for the insights farmers have from years of making a living on the farm. A biologist may never have come up with the idea of fighting the tuber moth with lime and garlic.

People of different professions can have different goals and methods, even when they work on the same topic, which is all the more reason why they should share ideas with each other.

Related blog stories

Zoom to Titicaca

Acknowledgement

Israel Navarrete is an Ecuadorian expert on seed health, and a Ph.D. candidate at the University of Wageningen, in the Netherlands. His research is funded by the International Potato Center (CIP) and the McKnight Foundation’s Collaborative Crop Research Program (CCRP).

Further reading

Bentley, Jeffery W. 1994 “Facts, Fantasies and Failures of Farmer Participatory Research.” Agriculture and Human Values 11(2&3):140-150.

Photo

Photo by Veronika Vogel, courtesy of Israel Navarrete

 

EXPERIMENTOS QUE SE COMEN

Jeff Bentley 25 de julio del 2021

Aunque los agricultores y los científicos agrícolas comparten el mismo campo de estudio, tienen estilos experimentales completamente diferentes.

El año pasado, en Ecuador, el estudiante de doctorado Israel Navarrete animó a los agricultores a experimentar, y le llamó la atención el tiempo que les llevaba sólo elegir una pregunta de investigación. Mientras organizaba tres pequeños grupos de agricultores en la provincia de Cotopaxi, Israel descubrió que los lugareños podían tardar hasta tres reuniones sólo para elegir un tema. Algunos agricultores sentían que los otros miembros del grupo no les escuchaban. (Las roces y resentimientos son tan comunes en las comunidades campesinas como en los departamentos universitarios).

Uno de los pequeños grupos de Israel, formado exclusivamente por mujeres, se dedicaba a cultivar papas y maíz negro. Al igual que los agricultores y agricultoras del Lago Titicaca sobre las que escribí hace poco, las ecuatorianas tenían problemas con las polillas de la papa que destruían su semilla de papa. Estas agricultoras de Cotopaxi decidieron finalmente ver si podían controlar las polillas tratando su semilla con extracto de ajo y con “cementina” (un tipo de cal para la construcción).

Israel les animó a hacer múltiples réplicas del experimento. Las réplicas (repeticiones simultáneas del experimento) son un fundamento del método científico, y son especialmente importantes en la agricultura, donde cada parcela de tierra, cada lote de semillas es algo único, como los copos de nieve. Hay que probar una idea varias veces para ver si el resultado es consistente y no es una mera casualidad.

Pero las agricultoras de Cotopaxi se negaron a usar réplicas y se limitaron a probar la cal y el ajo en un solo lote de semilla. La solución pareció funcionar, por lo que Israel animó a las mujeres a probarlo de nuevo, tal vez en diferentes tratamientos (como la cal sola, o el ajo solo, y ambos juntos). Pero las agricultoras se negaron. Estaban satisfechos con los resultados.

Al explicar esta experiencia, Israel trató de ocultar su frustración de que los agricultores no quisieran trabajar en el experimento con más detalle. Se mostró filosófico sobre los resultados. Dijo: “Los agricultores toman una idea complicada y la prueban de forma sencilla, mientras que los investigadores toman una idea sencilla y la prueban de forma complicada”.

Gran parte del método científico está diseñado para mostrar una verdad universal. El experimento tiene que ser replicable y estar descrito en números y publicado. Una vez recolectados los datos, el experimento puede desecharse.

Para los agricultores, el experimento no tiene que ser replicable. Sólo tiene que conseguir resultados en su finca. No necesita números porque los agricultores buscan grandes diferencias cualitativas. O se elimina la polilla de la papa, o no. Y a diferencia de los científicos, los agricultores tienen que vivir del experimento en sí. En este caso, los agricultores sembraron la semilla de papa que habían rociado con cal y ajo.

Los científicos redactan el experimento y lo publican. Es parte de su trabajo. Los agricultores aprenden del experimento y se lo comen. Es parte de su vida.

A pesar de tener estilos experimentales bien diferentes, la colaboración entre los pequeños agricultores y los investigadores es valiosa por los conocimientos que tienen los agricultores tras años de ganarse la vida trabajando la tierra. Puede que a un biólogo no se le haya ocurrido nunca la idea de combatir la polilla del tubérculo con cal y ajo.

Personas de distintas profesiones pueden tener objetivos y métodos diferentes, incluso cuando trabajan en el mismo tema, y justo por eso vale la pena que compartan ideas entre sí.

Historias relacionadas en el blog de Agro-Insight

Zoom al Titicaca

Agradecimiento

Israel Navarrete es un experto ecuatoriano en la sanidad de las semillas, y candidato a PhD en la Universidad de Wageningen, en los Países Bajos. Su investigación está financiada por el Centro Internacional de la Papa (CIP) y el Programa Colaborativo de Investigación de Cultivos (CCRP) de la Fundación McKnight.

Lectura adicional

Bentley, Jeffery W. 1990 “La Participación de los Agricultores en Hechos, Fantasías y Fracasos: Introducción a la Memoria del Simposio.” Ceiba 31(2):29-41.

Foto

Foto por Veronika Vogel, cortesía de Israel Navarrete

 

Black fire ants July 11th, 2021 by

The surest way to tell if you have black fire ants in your garden is to accidentally stand on or near their nest. The ants will crawl through your clothes first and then start stinging you all at once. You may have to go inside and take off your trousers to find all of the ants in your pants. A second diagnostic test of black fire ants is to plant a vegetable seedbed, and wait for it to come up, but it never does. The ants have eaten all your seeds.

These ants love seeds and they will dig up every one you plant in their foraging area.

You can try dousing their nest with boiling water, insecticide or gasoline (and then lighting it). I’m just kidding, but it may not even work; these ants are pretty tough. Or you can take Rachel Carson’s suggestion, and fight pests with biology, not chemistry.

Years ago, while working with my student Eloy González on his entomology thesis at El Zamorano, Honduras, by total serendipity we learned that fire ants can be perfectly controlled with raw grains of rice.

Here’s how it works. Plant your vegetable seedbed any way you like. Then sprinkle a handful of raw rice over the surface. The black fire ants are omnivorous, but they prefer dense food packages like seeds or other insects. The ants also know a bargain when they see one. The ants will haul off your rice grains and ignore your smaller, harder-to reach soil-covered vegetable seeds.

Once your vegetables come up, the black fire ants will lose interest in them. However, the ants will continue to patrol your vegetable patch, looking for insect pests to drag back to their nest, to eat.

If you don’t want to use rice, try bread crumbs, bits of stale tortillas or other food scraps.

In our garden, we have had no insect pests, except for the Mediterranean fruit flies. Our patchwork of many species of trees and vegetables confuses most insect pests. And because we have never applied insecticides, we have many beneficial insects that kill most of the herbivorous ones before they can become pests. We manage our black fire ants with the rice trick, and by not standing on their nests. They repay us by helping to keep our vegetables pest-free.

If you live outside of tropical Central or South America, you may never have to deal with black fire ants. But wherever you live, you can always look for ways to live with insects, with biology, not chemistry.

Further reading

Paul has his own story about Vietnamese farmers who educate weaver ants, to protect their orchards from insect pests.

Ants as friends.

Related Agro-Insight blog stories

Ants in the kitchen

Sugar sweet ants

The smell of ants

When ants and microbes join hands

Videos about insects that hunt and control insect pests, from Access Agriculture

The wasp that protects our crops

Promoting weaver ants in your orchard

Weaver ants against fruit flies

Scientific names

The black fire ant, also called the tropical fire ant, is Solenopsis genimata. The red fire ant, the so-called “imported” one is Solenopsis invicta. The red fire ant is native to Argentina, and slipped into the USA, possibly as a stowaway on a ship, after 1933. in Silent Spring, Rachel Carson tells the story of how the US Department of Agriculture lost its chemical war against the red fire ant. That red ant is still thriving in North America. Unlike the black fire ant, which builds discrete, ground-level nests, the red one builds, a tall, conspicuous entrance to its burrow.

Zoom to Titicaca June 6th, 2021 by

Vea la versión en español a continuación

Covid may be the world’s most spectacular emerging disease, but agriculture has its own new pests and diseases. Fortunately, collaboration between agronomists and farmers can offer solutions, as I saw in a recent meeting on the shores of Lake Titicaca.

This is 2021, so we met on Zoom, but I was struck by how much the meeting resembled others I have attended in person with farmers and agronomists.

Ing. Sonia Laura, a researcher from Prosuco who works closely with farmers, had driven out to the village of Iquichachi, a couple of hours from La Paz. Sonia set up the call on her laptop, and the farmers (Sra. Cristina, Sra. Arminda, Sr. Juan, Sr. Paulino, Sr. Zenobio, and Sr. Fidel) all managed to squeeze onto the screen. Bundled up in coats and hats against the high Andean cold, they explained how several years ago, they noticed a new worm eating the potatoes they store at home.

The moth lays its eggs on stored potatoes, and on potato plants in the field. The eggs hatch into caterpillars that go back and forth: from field to home in the harvest, and from storage to field with the seed.

The farmers showed some graphs of data they had been collecting with Sonia, under advice from Ing. Reinaldo Quispe, an agronomist from Proinpa, who joined the call from his office in La Paz. Reinaldo and the farmers had been using the sex scent (pheromone) of female moths to attract and trap the male moths. Each moth species has its own unique sex pheromone. Reinaldo had identified the pests, two related species of tuber moths, native to the Andes, but usually found in the lower, warmer valleys. Both species belong to a moth family that specializes in infesting stored foods.

The agronomist Raúl Ccanto joined us from Peru, from the NGO Yanapai. Raúl explained that Peruvian farmers had suffered from these two moths for many years. Over the years of working with the farmers, Yanapai and others had developed some practical solutions.

As Raúl explained, select the seed carefully. When you take seed from the house to plant in the field, make sure that you only plant healthy tubers, not the ones full of worms.

Also rotate your crops. “This is something you farmers have always done, but it’s important to say that it is a good thing.” Growing potatoes one year, followed by other roots and tubers (such as oca and papalisa, which are not of the potato family), and then other legumes and cereals, helps to keep the soil free of potato pests.

Raúl’s PowerPoint included the results of experiments, done in collaboration with Peruvian farmers, where they tried various ways to manage the moths in stored seed potato. One idea that worked well, and was also cheap, was to dust healthy seed potatoes with talc, which keeps the moths from laying their eggs in potatoes. The talc worked almost as well as malathion, the insecticide.

Raúl skipped lightly over the malathion, barely mentioning it, and for good reason. He had included the chemical treatment in the experiment as a comparison, but he was not promoting it. As Reinaldo explained, farmers often prefer insecticides and use them even in stored potatoes, which one should not do.

In fact, medical schools in Bolivia teach their third-year students to diagnose and treat malathion poisoning, because it is common. “This is something you’ll see,” the older doctors tell their students.

With any new pest or disease, it’s important to know where it came from. Raúl explained that the moths may have recently colonized the cold Altiplano, not just because of climate change, but also because people are bringing wormy seed in from fairs in distant parts of the country. And they are growing more potatoes. As more of the land is planted more often and over larger areas, to meet market demand, a more attractive environment is created for potato pests.

Yes, the farmers agreed, potatoes are being grown more often. And that is why it is crucial for scientists and farmers to put their heads together, to confirm useful ideas, from different perspectives.

The farmers wanted to know if there was something they could apply to their potatoes, to kill the moth. Raúl and Reinaldo both explained that there is no one thing that will manage the pest. It will have to be managed by rotating crops, and by selecting healthy seed. Other ideas like dusting the potatoes with talc will also help. The good news is that the moths can be managed.

It may be in human nature to yearn for simple solutions. Many of us have simply wished that Covid would go away, and that things would go back to normal. Like Covid, managing the tuber moth will require several good ideas, well explained, widely shared and applied.

In this case, the new information motivated the farmers to set up their own experiments. Sonia told me that after our call, the farmers met to reflect and take action. They decided that each one of them would select their seed, clean their potato storeroom, and sprinkle talc on the selected seed. They will keep using the pheromone traps, among other things. Later, they will explain these practices to their other community members, to take action as a group.

Scientific names

The tuber moths are Phthorimaea operculella and Symmetrischema tangolias (Lepidoptea: Gelechiidae).

Oca (Oxalis tuberosa) and papalisa (Ullucus tuberosus) are native Andean crops, not widely grown outside the region. The papalisa is also called “olluco” in Peru.

Talc is a clay mineral, magnesium silicate, a natural stone that is ground to make a powder.

Acknowledgements

Sonia Laura works with María Quispe at Prosuco (Promoción de la Sustentabilidad y Conocimientos Compartidos) in La Paz.

Raúl Ccanto works at Grupo Yanapai (meaning “to help” in Quechua), in Peru.

Reinaldo Quispe works at Proinpa (Fundación para la Promoción e Investigación de Productos Andinos), Bolivia.

The work with the Andean tuber moths is supported by the McKnight Foundation’s CCRP (Collaborative Crop Research Program).

Thanks to Sonia Laura and to Paul Van Mele for reading a previous version of this story.

Photos

Thanks also to Sonia Laura for her beautiful photographs.

ZOOM AL TITICACA

Por Jeff Bentley, 6 de junio del 2021

El Covid-19 podría ser la enfermedad nueva más espectacular del mundo, pero la agricultura tiene sus propias plagas y enfermedades emergentes. Afortunadamente, la colaboración entre agrónomos y agricultores puede ofrecer soluciones, como vi en una reciente reunión a orillas del Lago Titicaca.

Estamos en el 2021, así que nos reunimos por Zoom, pero me sorprendió lo mucho que se parecía la reunión a otras a las que he asistido en persona con agricultores y agrónomos.

La Ing. Sonia Laura, una investigadora de Prosuco, que trabaja estrechamente con los agricultores, había ido en camioneta hasta la comunidad rural de Iquicachi, a un par de horas de La Paz. Sonia organizó la llamada en su laptop, y los agricultores (las y los señores Cristina, Arminda y Juan, Paulino, Zenobio, Fidel,) se hicieron entrar todos en la pantalla. Abrigados con chompas y gorros contra el frío altoandino, explicaron que hace pocos años se dieron cuenta de que un nuevo gusano se comía las papas que almacenaban en sus casas.

La polilla de papa pone sus huevos en las papas almacenadas y en las plantas de papas en el campo. De los huevos nacen gusanos del campo, que van a casa en la cosecha, y del almacén regresan a la chacra con la semilla.

Los agricultores mostraron algunos gráficos de datos que habían estado recopilando con Sonia, bajo la orientación del Ing. Reinaldo Quispe, de Proinpa, quien se unió a la llamada desde su oficina en La Paz. Sonia y los agricultores habían estado usando el olor sexual (feromona) de las polillas hembras para atraer y atrapar a las polillas macho. Cada especie de polilla tiene su propia feromona sexual. Reinaldo había identificado las plagas, dos especies relacionadas de polillas del tubérculo, nativas de los Andes, pero que suelen encontrarse en los valles más bajos y cálidos. Ambas especies pertenecen a una familia de polillas especializada en infestar alimentos almacenados.

Desde Perú nos acompañó el agrónomo Raúl Ccanto, de la ONG Yanapai. Raúl explicó que los agricultores peruanos habían sufrido estas dos polillas durante muchos años. A lo largo de sus años de trabajo con los agricultores, Yanapai y otros han desarrollado algunas soluciones prácticas.

Como explicó Raúl, hay que seleccionar la semilla con cuidado. Cuando saques la semilla de la casa para sembrarla, asegúrate de plantar sólo los tubérculos sanos, no los que están llenos de gusanos.

También hay que rotar los cultivos. “Esto es algo que ustedes los agricultores siempre han hecho, pero es importante decir que es bueno que lo hagan”. Lo que ayuda a mantener el suelo libre de plagas de la papa es cultivarlas solo un año, seguido de otras raíces y tubérculos (como la oca y la papalisa, que no son de la familia de la papa), y luego sembrar leguminosas y cereales.

La presentación de Raúl incluyó los resultados de los experimentos, realizados en colaboración con agricultores peruanos, en los que se probaron varias formas de controlar las polillas en los almacenes de semillas de papa. Una idea que funcionó bien, y que además era barata, fue rociar la papa seleccionada con talco, que impide que las polillas pongan sus huevos en las papas. El talco funcionaba casi tan bien como el malatión, el insecticida.

Raúl pasó por alto el malatión; apenas lo mencionó, y con razón. Había incluido el tratamiento químico en el experimento como comparación, pero no lo promovía. Como explicó Reinaldo, los agricultores suelen preferir los insecticidas y los usan incluso en las papas almacenadas, lo cual no se debe hacer.

De hecho, las facultades de medicina de Bolivia enseñan a sus estudiantes de tercer año a diagnosticar y tratar la intoxicación por malatión, porque es algo común. “Esto es algo que van a ver”, dicen los doctores a sus alumnos.

Con cualquier plaga o enfermedad nueva, es importante saber de dónde viene. Raúl explicó que las polillas pueden haber colonizado recientemente el frío Altiplano, no sólo por el cambio climático, sino también porque la gente está trayendo semillas agusanadas de ferias en otras partes del país. Y están cultivando más papas sobre mayor superficie. A medida que se siembra más seguido y en más área, para satisfacer la demanda del mercado, se crea un ambiente más atractivo para las plagas de la papa.

Sí, los agricultores reconocieron que hoy en día las papas se cultivan más seguido. Y por eso es crucial que científicos y agricultores compartan sus ideas, para confirmar las que son útiles.

Los agricultores querían saber si había algo que pudieran aplicar a sus papas para matar la polilla. Raúl y Reinaldo explicaron que no hay una sola cosa que la pueda manejar. Habrá que controlar la plaga mediante la rotación de cultivos y la buena selección de semillas. Otras ideas, como aplicar talco a las papas, también ayudarán. La buena noticia es que las polillas sí tienen solución.

Tal vez algo en la naturaleza humana anhela las soluciones sencillas. Muchos hemos deseado que el Covid desaparezca de una sola vez, y que las cosas vuelvan a la normalidad. Al igual que el Covid, el manejo de la polilla de la papa requerirá varias buenas ideas, bien explicadas, ampliamente compartidas y competentemente aplicadas.

En este caso, la nueva información motivó la gente a armar sus propios experimentos. Sonia me informa que se reunieron para reflexionar y tomar acuerdos. Decidieron que cada persona del grupo haría la selección de semilla. Limpiaría su almacén de papas, y pondría talco en las papas seleccionadas. Seguirán con las trampas con feromonas, entre otras cosas. Luego comunicarán estas prácticas en una reunión con toda la comunidad para tener un trabajo comunal en el control de esta plaga.

Nombres científicos

Las polillas de la papa son Phthorimaea operculella y Symmetrischema tangolias (Lepidoptea: Gelechiidae).

La oca (Oxalis tuberosa) y la papalisa (Ullucus tuberosus) son cultivos nativos andinos, poco cultivados fuera de la región. La papalisa también se llama “olluco” en el Perú.

El talco es silicato de magnesio. Es una piedra natural que se muele para obtener el polvo. Como explica Raúl Ccanto, es un “mineral no metálico”.

Agradecimientos

Sonia Laura trabaja con María Quispe en Prosuco (Promoción de la Sustentabilidad y Conocimientos Compartidos) en La Paz.

Raúl Ccanto trabaja en el Grupo Yanapai (que significa “ayudar” en quechua), en el Perú.

Reinaldo Quispe trabaja en Proinpa (Fundación para la Promoción e Investigación de Productos Andinos), en Bolivia.

El trabajo con las polillas de la papa está apoyado por el CCRP (Programa Colaborativo de Investigación de Cultivos) de la Fundación McKnight.

Gracias a Sonia Laura y a Paul Van Mele por leer una versión previa de este relato.

Fotos

Gracias también a Sonia Laura por sus hermosas fotos.

Our threatened farmers May 9th, 2021 by

Supermarkets in the USA bulge with everything from strawberries to steak, but this generous supply is threatened by a destructive agro-industry. In the recent book Perilous Bounty, Tom Philpott outlines looming disasters in California and the Midwest.

The Central Valley of California produces an astounding 80% of the world’s almonds and half of the pistachios, besides a lot of the fresh fruits and vegetables eaten in the USA. This phenomenal production is irrigated with water that is mined, and can never be replaced. The Central Valley used to be a vast wetland. From 1930 to 1970 a network of dams and canals were built to capture snowmelt from the Sierra Madre mountains, for irrigation.

But the rainfall out west is erratic and some years there is not enough snow to irrigate all the nut trees, so well water makes up the difference. So much water has been pumped that the ground level has fallen by 29 feet (8.8 meters). As the subsoil shrinks, it loses capacity; it can now hold less water than before.

The Midwest used to be a home for diversified family farms, rotating crops of corn, wheat, oats and rye, and even growing fruits and vegetables. Cattle ate fodder produced on the farm itself. Since the 1960s, this integrated system has been replaced by a simpler one, of just maize (corn) and soybeans, while the livestock have been sent to factory farms. Crops and animals are now grown on separate farms. The hog mega-barns are so far from the grain farms that the pig manure cannot be used as fertilizer. Instead, the manure finds its way to the Mississippi River and on to the Gulf of Mexico, where it has created a dead zone the size of New Jersey, destroying a thriving fish and shrimp industry. The soil is now eroding at an estimated rate of 5.4 tons per acre per year (13.5 tons per ha). The rich black soil is vanishing fast.

A handful of corporations buy meat (Tyson Foods, Cargill, JBS, and Smithfield Foods—owned by the Chinese WH Group) and just four companies make most of the chemical fertilizer in the USA, so farmers are forced to take the prices offered by these few buyers and sellers. This price squeeze forces many family farmers out of business. Between 1940 and 2018, the number of farms in Iowa declined from 213,000 to 86,000, a loss of 60%.

Much of this chemical-intensive farming system operates at a loss, but is made profitable by Federal Crop Insurance, operated by private companies, but subsidized by the US government.

Agriculture does make money for big companies. Monsanto, a corporation that made agrochemicals, saw its value rise from $5 billion in 2000 to $66 Billion in 2018, when Bayer bought the company. During these years, Monsanto consolidated its hold on the seed and pesticide industry. Almost all of the maize, soybean and cotton in the USA is now grown from varieties that have been genetically modified to withstand herbicides, especially glyphosate, sold under the brand name Roundup. At first, farmers loved it. They could plant the genetically modified “Roundup Ready” seed and then spray the emerging plants with herbicides, killing all the weeds and leaving the maize or soybeans fresh and green.

The problem is that weeds invariably evolve resistance to the herbicides. So, seed companies engineer new crop varieties that can withstand more herbicides. Then the weeds become resistant to those herbicides. And farmers have to spend more on seeds and chemicals.

There is a way out. In California, agroecologist Stephen Gliessman grows grapes without irrigation. In the Midwest, farmer-innovators like David Brandt and Tom Frantzen work with researchers to create integrated livestock-cereal farms where cover crops rebuild the soil with organic matter.

I was heartened to read about these inventive farmers. But there are other things we can all do, to live better and eat better. We can:

Plant a garden.

Buy locally, from family farmers.

Eat organic food.

Vote for lawmakers who support anti-trust legislation.

Push for more research on organic farming and agroecology.

Further reading

Philpott, Tom 2020 Perilous Bounty: The Looming Collapse of American Farming and How We Can Prevent It. New York: Bloomsbury Publishing. 246 pp.

Related Agro-Insight blogs

Out of space

Stuck in the middle

A revolution for our soil

Living soil: a film review

Against or with nature

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