Survey of Pest resistance to Bt crops

Jonas Kathage has posted a very approachable survey of Bt resistance issues and strategies at Biology Fortified, Inc. Jonas closes with the following discussion of both economics and resistance management strategies:

Meanwhile, entomologists are working on improving their incomplete understanding the complex mechanisms involved in resistance evolution. Recently published research suggests that pyramiding might not work as well in delaying resistance as previously thought. In the laboratory, scientists selected cotton bollworm (Helicoverpa zea) for resistance against Cry1Ac. They exposed the resistant insects and a susceptible control group to Bt cotton expressing Cry1Ac/Cry2Ab and found that the group resistant to Cry1Ac exhibited a much higher survival rate than the control group, violating the assumption of redundant killing that is crucial to this strategy. So far, despite multiple reported instances of resistant insects, large-scale failure of Bt crops due to evolved resistance has not occurred, but it may come sooner than expected.

Should refuge requirements be expanded?

This research finding is bad news because the potential of pyramided Bt crops might be lower than believed. (Actually, some scientists have been positively surprised at the long delays observed in resistance development.) Let’s assume the results also apply to other Bt pyramids and insect species (there is evidence to the contrary). What should be made of such a scenario? Should larger refuge areas be required?

Before answering that question, it must be recognized that the sustainable application of a particular technology is not a primary goal of farming. A much more important goal is efficiency. Efficiency means getting the most output (e.g. food) from a set of scarce inputs (natural resources, labor, capital). The technologies transforming inputs into outputs, be they biological, chemical, or mechanical, are valuable only insofar as they contribute towards efficiency.

When deciding whether to expand refuge requirements, policymakers must take into account that there is a tradeoff between the size of the refuge area and productivity. If refuge area increases, more plants will get damaged by pests and hence reduce effective yield. The crucial question is whether the benefits of delaying resistance outweigh the costs of these yield losses and other potential drawbacks of refuges such as the need for additional land, sprays, separation costs, and sowing and harvest times. Costs of monitoring compliance with refuge requirements must also be considered, while pyramiding will incur more R&D expenditures. (In some developing countries with larger monitoring costs, refuge requirements may be less efficient also because of natural refuge in small-scale cropping systems.) The point here is not to question whether the optimal refuge requirement is 0%, 20% or 40%, but to realize that there are costs that have to be weighed against benefits. It is possible that an arms race based on adding more Bt genes is more efficient than slowing resistance development by expanding mandated refuges.

Besides Bt crops, there is a host of other pest management options including chemical control, biological control and cultural control such as ploughing and crop rotation. Like Bt, they all have their particular drawbacks, be it risk of resistance development, low effectiveness, or environmental and economic cost. The most efficient pest management strategy depends on local context, but will involve multiple instruments. For breeders, genes producing insect toxins, whether introduced using conventional or GM techniques, are not the only route towards pest protection. There are exciting possibilities on the horizon, including transgenic plants that emit volatile organic compounds to repel herbivores or attract their natural enemies. The use of nano-silica that kill pests by purely physical means are just one example of potential applications of nanotechnology in pest management. New approaches will have benefits and costs to be assessed against existing alternatives. As of today, there are no magic bullets protecting crops from pests. But there are excellent reasons that we should keep looking for them. Bt will not be the end of the road.

Continue reading from the top…


True greens know GM is the answer

Mark Lynas has a short essay in the Sunday Times “True greens know GM is the answer”. I can’t find a way around the paywall, but there is a repost here.

Mark concludes his essay with this:

Not for nothing did Norman Borlaug, the late Nobel peace prize laureate who saved the world from famine in the 1970s and 1980s with his Green Revolution, spend his final years warning that anti-biotech activists would bring starvation back into the world if they succeeded in stopping GM.

Is Environmentalism Anti-Science?

We recommend Keith Kloor’s short essay on the anti-science, anti-GMO activists. Keith doesn’t discuss this, but aren’t there strong parallels to the anti-nuclear ideology? I speculate there is a lot of overlap between the two anti- populations. E.g., Greenpeace.

As I try to answer Keith’s captioned question, I think of the example environmentalists that we know by reading or personal contact. Those who have a science/engineering background are much more likely to be influenced by the data than by some politically-correct ideology. Can you name a person who understands the peer-reviewed literature who is anti-nuclear or anti-GMO?

We are pro-people and anti-anti. Our interest is how to feed ten billion affordably. Especially the Bottom Billion — that will grow to at least two bottom billion around 2050 – all wanting a share of the low-cost energy and low-cost food enjoyed by today’s rich countries. There are no anti-GMO activists amongst the hungry.

Here’s an excerpt from Keith:

(…) I’ve been particularly interested in this question lately. In doing some catch-up reading, I came across a fascinating roundtable of views in a 2009 Seed magazine article, set up by this introduction:

Most Europeans don’t consider themselves to be anti-science or particularly technophobic. In fact, Europe’s full embrace of the scientific consensus on another environmental issue, global warming, has enabled the continent to take the clear lead on climate change, with the most ambitious emissions targets, the first carbon trading market, and the greenest urban infrastructure plans on the planet.

Europe’s scientific disconnect is more broadly true of eco-minded citizens worldwide: They laud the likes of James Hansen and Rajendra Pachauri but shrink in horror at the scientist who offers up a Bt corn plant (even though numerous studies indicate that Bt crops—by dramatically curbing pesticide use—conserve biodiversity on farms and reduce chemical-related sickness among farmers).

So why the disconnect? Why do many environmentalists trust science when it comes to climate change but not when it comes to genetic engineering?

Before you click on the link to learn some of the proffered reasons, think about it first.

Another inconvenient truth for Take the Flour Back. GM saved the Hawaiian papaya industry from disease

David Tribe demonstrates how these vandals and their Green Party allies have no understanding of any of the relevant science. And like the anti-nuclear activists they are happy to continuously repeat falsehoods. Shameful.

British Green politician Jenny Jones has announced that she is going to join the Take the Flour Back protest group who are threatening to vandalise a legal trial of aphid protected GM wheat that’s now underway in Britain.

In her statement about this, besides announcing she joining a vandalism threat that’s euphemistically termed a “decontamination”, she makes a claim in justification that is simply false, and that false claim is that no successful disease resistant crops have been developed by genetic engineering methods.

She is misinformed about this.

More than one virus resistant crop has been commercialised, but the most famous example is papaya that resistant to papaya ring spot virus. These crops have been in the ground in Hawaii since the mid 90s and continue to be sold. Just recently they were approved for export to Japan. Sadly, because of the activities of political Greens and antitechnology activists the diffusion of this technology to South Asia where it could improve food security has been dramatically impeded. We can thank misinformed and wrong-headed people like Jenny Jones for that.

Read the whole thing »

Sir Richard Roberts Speaks Out on Genetic Modification, Synthetic Biology, Stem Cell Research

Sir Richard Roberts, the eminent British biologist and Nobel Prize laureate, said today European opposition to genetically modified organisms is political rather than scientific in nature.

This is a press release — I’ve not found a transcript of his remarks at the Astana Economic Forum:

(…) Roberts, who won the Nobel in 1993 for his shared discovery of split genes, made his remarks at the Astana Economic Forum, a global conference of scientists, academics, multinational executives and government leaders.

“On a political level, governments must embrace genetically modified organisms (GMOs) and not give way to European prophets of doom, who oppose the use of GMOs for purely political reasons,” said Roberts. “It is important to note there is a complete absence of evidence that GMOs can cause any harm. Indeed to any well-informed scientist, traditionally bred plants seem much more likely to be harmful than GMOs.”

Guest opinion: Two dozen studies show GM foods safe

Andrew Staehelin is a professor emeritus of the Department of Molecular, Cellular and Developmental Biology at the University of Colorado Boulder. Here he summarizes the peer-reviewed science on GM food safety.

In the 1990s the tabloid press in England discovered that it could make lots of money publishing scary articles about “Frankenstein foods.” Since then, opponents of plant genetic engineering have been claiming that eating GM (genetically modified) foods is dangerous. They like to quote Arpad Pusztai, who reported in 1999 that rats fed a diet of raw, experimental GM potatoes expressing a sugar-binding lectin protein developed a thicker gut epithelium than when fed control potatoes. These days, the Frankenstein food myth is being kept alive by non-reviewed Internet articles and YouTube videos posted on anti-GMO websites. Anti-GM food activists also claim that no studies by independent researchers have been conducted to show that such foods are safe.

In contradiction to these claims, independent researchers have been investigating the question whether GM foods pose a risk to public health for over a decade, and have published their findings in peer-reviewed journals. Recently, a landmark review paper written by seven European scientists and published in the journal Food and Chemical Toxicology has critically evaluated the results of 24 long-term GM food safety studies. The summary statement reads: “The studies… show that GM plants are nutritionally equivalent to their non-GM counterparts and can be safely used in food and feed.” Here are some of the details.

Read the whole thing »

Agriculture: toxic technophobia

Henry I. Miller at Project Syndicate:

(…) by yielding to the demands of a minuscule number of disingenuous activists, the companies opted to offer less safe products to consumers, thereby exposing themselves to legal jeopardy..

(…) Responding to the bleating of activists, policymakers have subjected the testing and commercialization of genetically engineered crops to unscientific and draconian regulations, with dire consequences. A groundbreaking study of the political economy of agricultural biotechnology concluded that over-regulation causes “delays in the global diffusion of proven technologies, resulting in a lower rate of growth in the global food supply and higher food prices.” Current policies also create “disincentives for investing in further research and development, resulting in a slowdown in innovation of second-generation technologies anticipated to introduce broad consumer and environmental benefits.”

Everyone involved in food production and consumption has suffered: consumers (especially in developing countries) have been subjected to avoidable health risks, and food producers have placed themselves in legal jeopardy for selling products known to have “design defects.”

The Inefficiency of Local Food

We highly recommend this Steve Sexton essay on Freakonomics. Steve is a Ph.D. candidate in agricultural and resource economics, and a regular Freakonomics contributor. Excerpt:

(…) Amid heightened concern about global climate change, it has become almost conventional wisdom that we must return to our agricultural roots in order to contain the carbon footprint of our food by shortening the distance it travels from farm to fork, and by reducing the quantity of carbon-intensive chemicals applied to our mono-cropped fields.

But implicit in the argument that local farming is better for the environment than industrial agriculture is an assumption that a “relocalized” food system can be just as efficient as today’s modern farming. That assumption is simply wrong. Today’s high crop yields and low costs reflect gains from specialization and trade, as well as scale and scope economies that would be forsaken under the food system that locavores endorse.

Specialization and Trade

Economists have long recognized the welfare gains from specialization and trade. The case for specialization is perhaps nowhere stronger than in agriculture, where the costs of production depend on natural resource endowments, such as temperature, rainfall, and sunlight, as well as soil quality, pest infestations, and land costs. Different crops demand different conditions and vary in their resilience to shocks. So California, with mild winters, warm summers, and fertile soils produces all U.S.-grown almonds and 80 percent of U.S. strawberries and grapes. Idaho, on the other hand, produces 30 percent of the country’s russet potatoes because warm days and cool nights during the season, combined with rich volcanic soils, make for ideal growing conditions.

Read the whole thing. You can read more of Steve’s research papers here at