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Biological pest control in the Galapagos forest July 14th, 2019 by

Agronomy is a kind of applied biology, but conservation biologists are now starting to apply some of the tricks from agriculture, as I saw on a recent visit to the Charles Darwin Research Station in the Galapagos Islands. The campus is tucked discretely into one of the world’s strangest forests, where some of the plants that were able to reach these remote islands have evolved into trees. Prickly pear cactus is usually a low-lying plant with paddle-like pads, but in the Galapagos, it has evolved a tall, straight trunk. The Scalesia trees evolved from a daisy-like flower.

Then in 1982, these rare trees were threatened when the cottony scale insect, originally from Australia, invaded the islands and began to feed on its odd collection of forest species, causing the dieback and death of trees. By 1996 the scale insect was attacking 80 plant species in the Galapagos, including 19 threatened ones.

Displays at the Darwin Station proudly explained their efforts to control the Australian scale insect by bringing in one of its natural enemies, a ladybird beetle, also from down under, that preys on the scale. In 1999, the British Embassy funded an insect containment center, where the ladybird was intensively studied before being released on 11 islands in 2003 and 2004. By 2009 the ladybird had hunted the cottony cushion scale down to a much lower population level. The forest was safe. 

The sign at the Darwin Station said that this was an example of biological pest control, but the display failed to mention that this was the second time that the Australian ladybird beetle had come to the rescue of trees. The first time was in California in 1888, when the ladybird was imported to successfully control scale insects in citrus.

So, conservation biology has learned a lesson from agriculture, specifically from biological pest control. It’s only fair: ecology has provided many key insights to agriculture. For example, Darwinian natural selection explains how pests evolve resistance to pesticides. Gene mapping has helped plant breeders to develop new crop varieties faster.

The Darwin Station is now working on other projects to control pests. For example, an introduced fly is attacking the emblematic finches in their nests, and the Darwin Station is taking eggs from the nests of the mangrove finch (the most endangered of the Galapagos finch species) and rearing the chicks by hand, safe from the flies. The Darwin Station is also rearing several tortoise species, protecting them from introduced rats that eat the tortoise eggs. When the tortoises are two-years old they are released, each species to its own home island.

Agriculture has much experience reproducing plants and animals, and controlling pests in ecologically-sound ways. In the future, plant and animal species can be brought back from the brink of extinction, but it will take more than just conserving their habitat. Individual animals will have to be nurtured, helped to breed in higher numbers, and protected from pests. Conservation biology is becoming more hands on, more like farming and ranching. In the future, other lessons from agriculture may also of use to wildlife conservationists.

Scientific names

The finch-killing fly, Philornis downsi

The ladybird beetle, Rodolia cardinalis

The cushiony cotton scale insect: Icerya purchase

Prickly pear, Opuntia echios

MMangrove finch, Camarhychus heliobatis

Planting a wrong image July 7th, 2019 by

A picture says more than a thousand words. And pictures stick better in the mind. On a recent visit to the organic farm shop Eikelenhof, run by our friends Johan and Vera, I was reminded how easy it is for wrong images to become received knowledge.

Vera was talking to Peter, a plastic artist from the neighbourhood and one of the regular customers at the farm shop. The past few days we had had quite some severe storms and Peter was telling how the gusty winds had taken their toll with broken branches and uprooted trees as a result. Uprooted trees and heavy soil erosion are some of the few occasions when people get to see a glimpse of how the roots of mature trees look like. When they continued discussing about tree roots, both said that the roots are a mirror of the tree canopy. At that stage I intervened and started explaining how this image survived for centuries, but that this was absolutely wrong. Vera and Peter are both clever successful people, but like many of us, it is hard for them to shake off an image that has been impressed in their minds.

In the 19th century, Charles Darwin was making history with his research on how species had evolved over millions of years. The scientific revolution and the age of exploration ignited a growing interest in exotic plants and the economic potential they might have, leading to the boom of botanical gardens across Europe. These events also triggered a general interest in nature overall, and especially in England this passion for gardens has lived on until today.

When a 19th century graphic artist diverted from the botanical drawing style, which was based on accurate observations, he drew from imagination a stylistic tree with the roots being as a mirror of the canopy. He had no idea how it would impact on future generations. Helped by the technical breakthrough of offset printing and emerging media houses, this image made its way across Europe and firmy established in the minds of ordinary folks. Until today, hundreds of variations continue to be developed and spread, further feeding this misperception.

But my friends at the farm shop in Belgium are not the only people who accept the received wisdom that a tree’s roots mirror its branches. Even Thai farmers have taken the idea on board. When visiting a mango project in Thailand some 20 years ago, I recall visiting orchards where farmers had dug a trench just below the edge of the tree canopy to irrigate and put some organic fertilizer. It was explained to me that this was the zone where all the feeder roots of the trees could be found. Until today, tree roots are poorly studied, partly because they are hard to observe.

Fortunately, many of the 19th century illustrators painted accurate pictures of the natural world, which led to a greater understanding of natural history. Whether we illustrate with water colors or with video, it is important to get the picture right.

Related blogs

Travels around the sun

A gift of music June 30th, 2019 by

A gift of music

Marcella Vrolijks, who films and edits the Agro-Insight videos, has an ear for music. She starts and ends each video with a few riffs of music from the country where it was filmed. She has a gift for making the music fit the action. In one video where people in Mali are planting millet, Marcella added a West African beat that matched the rhythms of the hoes and hands so perfectly that others have asked if the music was playing while the farmers were being filmed. Another time, in Togo, the farmers themselves had composed a song about mucuna (velvet bean) and Marcelle starts the video with the women performing their own tune.

So, when Marcella and Paul came to film in Bolivia late last year, I took them to see something I knew they would appreciate – the Musical Instrument Museum in La Paz. There we met Ernesto Cavour, who is often called the greatest charango player in the world. A small stringed instrument with a curved body, the charango was originally made from armadillo shells. Nowadays they’re usually carved from wood.

Don Ernesto will be 80 next year. He grew up fascinated by the music created by campesinos playing their charangos. Don Ernesto taught himself to play the charango, formed a band and toured Europe, North America and Japan while he was still quite young. He loved every performance, but he came back to Bolivia to play and to teach people about music. He bought a house on Calle Jaén, a narrow cobblestone street in the old town of La Paz which is only accessible on foot. Here he publishes books about music and displays the traditional musical instruments of Bolivia in the museum he made. Don Ernesto is not only a scholar and player of the charango but an inventor too. He has created 30 new instruments, including the muyu-muyu, a charango which is strung on both sides of the body, giving an extended tonal range.

At the museum, we heard don Ernesto play with his daughter, Kantuta Cavour, and fellow musicians. Their musical style ranged from traditional Andean tunes, to those that incorporated representations of bird song, animal noises and the sound of rain made by instruments or the inventos created by don Ernesto.

Later we asked Kantuta if we could use their music for a small set of farmer educational videos. She thought her father would like the idea, and he readily agreed.

Marcella painstakingly reviewed dozens of don Ernesto’s songs to weave the music into the videos. Two of the videos were about weather, and Marcella was able to blend some of the musical rain with shots of storm clouds. I often think of the Cavours’ generosity. Their respect for tradition and love of innovation mirror our own ideals at Agro-Insight for an agriculture that creatively blends the old and the new.

Watch the videos

The planting video (Grow row by row)

Reviving soils with mucuna

Living windbreaks to protect the soil

Recording the weather

Forecasting the weather with an app

Visit the Music Museum

Museo de Instrumentos Musicales de Bolivia

Additional reading

Los Tiempos 2019 “Ernesto Cavour” Revista Oh! No. 1046 (16 July) pp 2-3.

When ants and microbes join hands June 23rd, 2019 by

When I recently attended the 1st International Conference on Agroecology – Transforming Agriculture & Food Systems in Africa, one of the research posters on display drew my attention. Effective microorganisms® are a commercial mix of beneficial bacteria, yeast and other living things. A team in Mozambique had found that the microorganisms not only controlled Oidium, a serious fungal disease in cashew, but also managed the devastating sap-sucking bug that deforms nuts and causes their premature fall. Or at least that is what the title said.

Professor Panfilo Tabora had been working for many years with cashew. Not knowing that I was an avid fan of the weaver ant, Oecophylla, a tree-dwelling predator, Panfilo gently explained to me that the microorganisms attracted the weaver ant to the cashew trees. “The ants were a bonus,” he said with a smile. I knew that weaver ants effectively control bugs, but now I was completely intrigued: how on earth would microorganisms attract ants?

“Earlier, farmers helped the weaver ants to colonize new trees by putting ropes between trees so the ants could colonise new trees and attack bugs and other pests,” Panfilo explained me. “But when farmers started spraying fungicides the ants disappeared.”

For several years, Panfilo and his colleagues began to teach villagers to make their own liquid molasses from dried and stored cashew apples as a source of sugar, minerals and amino acids to feed and multiply the microorganisms. So the farmers made molasses to feed the effective microorganisms, which controlled the Oidium. But even when the fermented solution was ready to spray on the trees it was still sweet. “When farmers spray their trees with the solution, the sweet liquid and amino acids attracts the ants.”

Although the poster did not tell the full story, there was still truth in saying that microorganisms controlled the fungal disease and the pest, in reality it was the fermented solution that attracted the ants, which controlled the bugs. Still, even such a roundabout pest control is worth having.  

I felt reassured to know that valuable ancient technologies of biological control, such as weaver ant husbandry, have a future when combined with modern agroecological technologies that restore rather than kill ecosystems.

“And we discovered a few more unintended benefits,” Professor Panfilo continued. “By spraying the tree canopies with microorganisms, farmers are no longer exposed to pesticides and can reduce the cost of pruning.” As pesticides are expensive and harmful, farmers need to move quickly from one tree to the next to spray the outside canopy of the trees, or else they will get covered with chemicals. But as these effective microorganisms are safe for people, farmers can actually spray the under-canopies from below. The tree canopies often touch one another, which also helps the ants to move between trees. Instead of pruning every year, Prof Panfilo’s team tells farmers to just prune once every other year, or even every three years so as to have more terminals for flowering and fruiting and to let the ants move from tree to tree. All of this adds up to more yield.

At that stage, I was so impressed that I had a hard time absorbing yet another unintended benefit of this organic technology. In Mozambique, as in many other countries, farmers use the fallen cashew apples to make cashew apple juice. “By spraying cashew trees with effective microorganisms, it acts as an anti-oxidant so the juice retains its clear colour for at least 2 months,” said Panfilo.

Quite a few of the presentations at the conference had nicely illustrated the benefits of organic agriculture to people and the environment, but Prof Panfilo and his team stood out because they illustrated how the introduction of even a single, modern eco-technology can have such a wide range of benefits.

Not all microorganisms are bad, as people in the industry, schools and media often wants us to make believe. Thanks to the work of practical researchers, we learn that this healthy mix of microscopic flora can cure mildew, attract ants that kill pests, provide a safe alternative to pesticides and stop cashew fruit juice from oxidizing for months.

Related blogs

Effective micro-organisms

The smell of ants

Ants in the kitchen

Related videos

Good microbes for plants and soil

Promoting weaver ants in your orchard

Weaver ants against fruit flies

Preparing cashew apple juice

Forgetting Inca technology June 16th, 2019 by

No one knows how the Incas built their famous temples and palaces. Ordinary Inca houses were made of uncut field stones, with no mortar. But their palaces and temples were built in a style of fine masonry, with stones of irregular shapes, yet cut so precisely that they fit together perfectly. Inca fine masonry is one of the wonders of ancient engineering. The late Swiss historian, Armin Bollinger, writes that the stones even “dance” in place during earthquakes, before settling back into their original position.

Previous Andean cultures worked with large stones placed close together, but in simpler patterns than the unique, high art of fine masonry used during the Inca Empire (about 1425 to 1532 AD). The massive pre-Inca blocks at the prehistoric city of Tiwanaku are placed side-by-side, as rectangles, not in the Inca pattern, where each stone is of a unique size and shape.

Even the conquistadores admired the Inca stonework, yet the Spaniards never saw the walls being built. After the conquest, the Incas never built in their finest tradition again, as the Spanish directed them to build in the European style instead.

Bollinger dismissed some common theories of how the walls were made, such as the idea that the blocks were put in place, then taken off and chipped some more before being put back in place, over and over until the fit was perfect. Many of the blocks were too big for that, since they weighed over 20 tons. Another theory is that the Inca masons rubbed the stones together, back and forth until they fit perfectly together. But the stones were mostly andesite, a basalt-like stone that is too hard to work just by rubbing.

Both of these ideas rely on using mass amounts of brute force. Bollinger no doubt would have preferred a theory that also included smart engineering and careful measurement to explain how the stones were fitted. But that knowledge is simply lost. Inca fine masonry has never been documented, nor reinvented, not even with the help of machinery. Although in a recent experience, Brandon Clifford (MIT) and Wes McGee (Univ. Michigan) get pretty close, with digital technology, glue, with small blocks made of concrete, and robotic arms to do the carving.

Technology is a game of use it or lose it. Whether it is a style of masonry, or of farming, even ingenious techniques can be lost if they are not used.

Agricultural knowledge has been evolving for at least 5000 years, a lot longer than the Inca stone walls have existed. As farmers adapt their knowledge to make it relevant in a changing world, it is important to respect, document and keep that knowledge alive which is not only clever: it feeds us. It is in humanity’s interest to keep as many techniques on hand as possible, to remain adaptive. Human knowledge is fragile. It can vanish if it is not used.

Further reading

Bollinger, Armin 1997 Así Construían los Inkas. Cochabamba: Los Amigos del Libro. Translated by Rainer B. Podratz. Original title So Bauten die Inka.

Clifford, Brandon, and Wes McGee. 2015 “Digital Inca: An assembly method for free-form geometries.” Thomsen, M. R., Tamke, M., Gengnagel, C., Faircloth, B., & Scheurer, F. (Eds.). Modelling Behaviour. Springer. 173-186.

Related blogs

Feeding the ancient Andean state

Inka Raqay, up to the underworld

The sugar palms of Angkor Wat

Anasazi beans

Related videos

Almost all of the videos on www.accessagriculture.org show a sensitive mix of local knowledge and appropriate new ideas.  For example, there is a new series on herbal medicines for livestock from India, and a series on traditional Andean knowledge of the weather.

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