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Book Review: Chasing the Red Queen ─ The Evolutionary Race Between Agricultural Pests and Poisons

Chasing the Red Queenby Andy Dyer, reviewed by Chris Walters

It’s not often that satirical fiction offers a nearly perfect illustration of a scientific principle. Yet Lewis Carroll pulled it off in Through the Looking-Glass when Alice mentions to the Red Queen that running fast generally gets you someplace, at least in Alice’s experience.

“‘A slow sort of country!’ said the Queen. ‘Now, here, you see, it takes all of the running you can do to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!’”

For a while, as Andy Dyer tells it, agricultural chemistry — pesticides and herbicides — were able to run fast enough to produce earth-shaking results. Their success transformed the fundamental human activity of growing food. Then they fell behind, finally leading to GMOs and the rapid adaptations of pests targeted by biotech cultivars, a turn of events Dyer calls “utterly predictable.” When you’re talking about the evolutionary biology of crops, weeds and insects, you’re describing a zone where the Red Queen rules. Continue Reading →

Natural Plant Toxins Aid Bees

Bee1webResearchers studying the interaction between plants, pollinators and parasites report that in recent experiments, bees infected with a common intestinal parasite had reduced parasite levels in their guts after seven days if the bees also consumed natural toxins present in plant nectar.

In this early and most comprehensive study of its kind, researchers at the University of Massachusetts Amherst and Dartmouth College studied hundreds of eastern bumblebees, Bombus impatiens, and their intestinal parasite Crithidia bombi, using eight separate toxic chemicals, known as secondary metabolites, produced by plants to protect themselves against predators.

The eight chemicals studied were nicotine and anabasine found in the nectar of flowers in the tobacco family, caffeine from coffee and citrus nectar, amygdalin from almond nectar, aucubin and catalpol from turtlehead flowers, gallic acid from buckwheat nectar and thymol from basswood tree nectar.

They found that these chemicals in nectar reduced infection levels of the common bumblebee parasite by as much as 81 percent by seven days after infection.

UMass Amherst evolutionary ecologist Lynn Adler said, “We found that eating some of these compounds reduced pathogen load in the bumblebee’s gut, which not only may help the individual bees, but likely reduced the pathogen Crithidia spore load in their feces, which in turn should lead to a lower likelihood of transmitting the disease to other bees.”

She adds, “Because plants just sit there and can’t run away from things that want to eat them, they have evolved to be amazing chemists. They make biological compounds called secondary metabolites, which are chemicals not involved in growth or reproduction, to protect themselves. They are amazing in the diversity of what they can produce for protecting themselves or for attracting pollinators.”

Adler says results may have implications for growers who depend on pollinators, who may want to think about planting pollinator-friendly hedgerows and gardens containing plants that produce natural herbal remedies for some of the common parasites and diseases that ail bees and other pollinating insects.

“The more we look, the more we see that these compounds are in nectar and pollen too,” she adds. “With so many people looking at bee health these days, it’s taken a long time for us to realize that perhaps we should be paying attention to how floral secondary compounds mediate pollinator dynamics and their interactions with pathogens. Having bees consume these protective chemicals could be a natural treatment of the future.”

Commercial honeybee growers already use one such chemical, thymol, found in thyme plants, to treat mite infestations.

Findings appear in Proceedings of the Royal Society B.

This article appears in the April 2015 issue of Acres U.S.A.

Plant Communities Beat Monocultures

Plant communities.tifAlthough monocultures can be cultivated efficiently, they are anything but sustainable: environmental damage to soil and water caused by monoculture cultivation is becoming increasingly evident, even beyond in-the-know sustainable farming circles. Despite their disadvantages, however, monocultures remain the principal crop form and are often regarded as the sole possibility for achieving higher yields in plant production — quite wrongfully, finds Bernhard

Schmid, an ecology professor at the University of Zurich. Schmid sees “an opportunity for the future of nutrition for humankind in the untapped potential of biodiversity” — a promising prospect as the OECD and the United Nations’ Food and Agriculture Organization (FAO) are giving off worrying signals: Both organizations predict that agricultural productivity will rise less steeply in the future than has been the case thus far.

In a 10-year study, a team of researchers from Switzerland, Germany and the Netherlands examined the yields from grassland plants which they had cultivated in monocultures or mixed plant communities. The latter proved to be more productive than the monocultures. Continue Reading →

Diversified Farming Better for Wildlife

diversified habitat.tifA study by scientists at Stanford and the University of California, Berkeley, published in Science, shows that evolutionarily distinct species suffer most heavily in intensively farmed areas. They also found, however, that an extraordinary amount of evolutionary history is sustained in diversified farming systems, which outlines a strategy for balancing agricultural activity and conservation efforts. The findings arise from a 12-year research project conducted by Stanford scientists at the intersections of farms and jungles in Costa Rica. Much of the research has focused on how farming practices can impact biodiversity, and has gone so far as to establish the economic value of pest-eating birds and crop-pollinating bees. Not surprisingly, the diversified farmlands supported on average 300 million years of evolutionary history fewer than forests. But they retained an astonishing 600 million more years of evolutionary history than the single crop farms.

This article appears in the November 2014 issue of Acres U.S.A.

Cover Crops for Pest Management

sunflower.tifTwo small farmers in Florida are partnering with University of Florida Extension to determine how cover crops can be used to manage insect pests. In a newly funded Southern Sustainable Agriculture Research & Education On-Farm Research Grant, “Establishing and Evaluating Selected Cover Crops on Small Farms to Increase the Impact of Beneficial Arthropods on Crop Pests,” strips of sunflower and buckwheat are being incorporated into crop fields to act as trap crops for pests and as attractants for beneficial predatory insects and pollinators.

Bradley Hoover, of Hoover Farms, owns 20 acres of about 50 different types of vegetables, all certified organically grown and sold in the wholesale market. In his field of tomatoes and peppers, Hoover, with the help of University of Florida Extension agents, has planted rows of sunflowers and buckwheat along the field perimeters, as well as additional rows of buckwheat in the center. The study compares the cover crops to the control (no cover crop plantings) to see where they fit into Integrated Pest Management practices.

The sunflowers attract stinkbugs, specifically the leaf-footed bug, which aggressively attacks tomatoes and peppers. The sunflower is acting as a trap crop, keeping the pest away from the farm’s cash crop. In addition, buckwheat attracts a wide array of beneficial insects, including native pollinators.

Scott and Billie Rooney, with Rooney’s Front Porch Farm, are looking at the same two cover crops, but evaluating their effectiveness in fruit production. Stinkbugs easily make a meal of their U-pick blackberry and blueberry plants.

“We are only in our first year of the study, but we are not seeing as many stinkbugs in the berries as we’ve had in the past,” said Billie Rooney.

Billie and her husband have already made some keen observations participating in the project. For example, she said that the sunflowers bordering the woodland contain more leaf-footed bugs than the sunflowers bordering their hair sheep grazing pasture.

The Rooneys are also interested in planting the winter small grain triticale in their grazing pastures. Triticale, it turns out, also acts as a trap crop for stinkbugs and will attract the early flights of stinkbugs before the sunflower crop is planted and ready.

This article appears in the September 2014 issue of Acres U.S.A.

Bugs as Bio-Control

Ascogaster_sp_(Cheloninae)

Image of an unidentified Ascogaster species.

University of Adelaide Ph.D. student Rebecca Kittel has discovered 18 new species of tiny parasitic chelonine wasps which have potential to be used as biological control (bio-control) agents as they specifically target individual varieties of moths.

The adult wasps inject their eggs into the eggs of host moths. The wasp larvae feed and develop inside of the moth caterpillars, emerging from the caterpillar as it dies. The larvae then form a cocoon until environmental conditions are right for the adult to emerge and the bio-control cycle begins again.

“The biology and the fact that each wasp species targets only one specific moth means that they are potentially ideal candidates for development as bio-control agents of agricultural pests,” says Kittel.

The wasps are among 150 new species discovered by Kittel. Specimens from around the country were sent to Kittel to identify, 250 of which were part of the 18 species published in her entry to the journal Insect Systematics & Evolution.

This article appears in the August 2014 issue of Acres U.S.A.