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Press Release

Farming for Improved Ecosystem Services Seen as Economically Feasible
April 2014

http://www.aibs.org/bioscience-press-releases/140407_farming_for_improved_ecosystem_services_seen_as_economically_feasible.html

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By changing row-crop management practices in economically and environmentally stable ways, US farms could contribute to improved water quality, biological diversity, pest suppression, and soil fertility while helping to stabilize the climate, according to an article in the May issue of BioScience. The article, based on research conducted over 25 years at the Kellogg Biological Station in southwest Michigan, further reports that Midwest farmers, especially those with large farms, appear willing to change their farming practices to provide these ecosystem services in exchange for payments. And a previously published survey showed that citizens are willing to make such payments for environmental services such as cleaner lakes.

The article is by G. Philip Robertson and six coauthors associated with the Kellogg Biological Station, which is part of the Long Term Ecological Research Network. The research analyzed by Robertson and colleagues investigated the yields and the environmental benefits achievable by growing corn, soybean, and winter wheat under regimes that use one third of the usual amount of fertilizer—or none at all—with “cover crops” fertilizing the fields in winter. The research also examined “no-till” techniques. The regime that used fewer chemicals resulted in more than 50 percent reductions in the amount of nitrogen that escaped into groundwater and rivers, with crop yields close to those of standard management. Nitrogen pollution is a major problem in inland waterways and coastal regions, where it contributes to the formation of “dead zones.”

The no-till and reduced chemical regimes also mitigated greenhouse warming by taking up greenhouse gases from the atmosphere, in contrast to standard management, which produces significant greenhouse warming by emitting nitrous oxide. The zero-chemical regime mitigated greenhouse warming enough to compensate for the emissions produced under standard management. All three regimes also led to more fertile soil compared with conventional management.

The environmentally improved farming practices that Robertson and his colleagues studied are more complex than conventional ones. But the authors found that although sustained profitability is generally farmers’ overriding concern, substantial proportions would accept payments to adopt such practices, especially those with large farms. And a 2009 survey in Michigan found that members of the public indicated they were willing to pay higher taxes so that land managers could participate in stewardship programs to benefit lakes; a smaller number were willing to pay for a reduction in greenhouse gas emissions.

Robertson and his colleagues argue that in coming decades, human population and income growth will drive agriculture to ever-higher intensities. The danger is that it will become more vulnerable to climate extremes and pest outbreaks. “Now is the time to guide this intensification in a way that enhances the delivery of ecosystems services that are not currently marketed,” they conclude.

This Overview and other articles in the May 2014 issue of BioScience are now published online as Advance Access at http://bioscience.oxfordjournals.org/content/early/recent .

BioScience is published monthly by Oxford Journals. Follow BioScience on Twitter @BioScienceAIBS.

Oxford Journals is a division of Oxford University Press. Oxford Journals publishes well over 300 academic and research journals covering a broad range of subject areas, two-thirds of which are published in collaboration with learned societies and other international organizations. The division been publishing journals for more than a century, and as part of the world’s oldest and largest university press, has more than 500 years of publishing expertise behind it. Follow Oxford Journals on Twitter @OxfordJournals

Jennifer Williams
Production Coordinator, BioScience

American Insitute of Biological Sciences (AIBS)
1900 Campus Commons Drive, Suite 200
Reston, VA 20191
703-674-2500 x209
jwilliams@aibs.org
http://www.aibs.org

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Yao-Hua Law

 

Speed read
Introduced Philidris ants cut cacao tree yields by aiding a pathogen’s spread

But trees with native ants had greater yields than those without any ants

Farmers who manage ant communities are also managing pests, says expert

 

[KUALA LUMPUR] Native ants living in cacao trees in Indonesia that are often seen as pests in fact seem to boost their yields, a study suggests.

Scientists from Germany, Indonesia and Sweden studying how ant communities affect cocoa yields in Sulawesi found that trees with abundant native ants (Dolichoderus sp.) produced the best yields. In contrast, the yields of cacao trees where ants were excluded were 27 per cent lower and those in which an invasive, foreign ant species (Philidris sp.) were introduced had yields that were 34 per cent lower, the study says.

The results were published last week (4 December) in Proceedings of the Royal Society B.
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“Farmers face many challenges and those who manage ant communities are also managing pests.”

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Stacy Philpott, University of California Arno Wielgoss, a graduate researcher from the University of Göttingen, Germany, and the lead scientist of the 16-month study, tells SciDev.Net that ants live in a mutualistic partnership with the mealybugs — insects that suck plant nutrients and excrete sugar to their guardian ants. But they also protect the cocoa pods from even more destructive pests such as cocoa pod borers and Helopeltis bugs.

The invasive Philidris ants transmit the fungus-like plant pathogen Phytophthora sp. and so the heaviest yield loss, according to the study. These ants collect pieces of Phytophthora-infected cocoa pods to build protective tents over the mealy bugs, it says. The study says that Philidris ants and their tent materials harbour infectious Phytophthora spores with which the ants contaminate fresh cocoa pods.

Indonesia is the world’s third biggest cocoa producer. But increased pest attacks and aging trees have slashed its production this year.

Worldwide, cocoa farmers struggle against severe but geographically limited pest infestations. Ants, which form part of the complex network of life in cocoa farms, are often seen as pests.

Farmers often dislike ants, says Stacy Philpott, an associate professor in agroecology at the University of California, Santa Cruz, who studies insects in another tree crop, coffee. She says that the study is important in advancing the understanding of the ecological roles that ants play.

Wielgoss warns that insecticide spraying could hasten Philidris dominance as “insecticides harm other ant species more than Philidris that are protected in their tents”. The spread of Philidris, he adds, would also be likely to aggravate Phytophthora infection.

Despite this, the effects of having Dolichoderus ants may vary, as a Malaysian Cocoa Board officer says that untreated cacao trees produce only half the yields of trees with ant treatment.

Philpott says: “Translating scientific results into practice can be difficult despite vigorous research. Farmers face many challenges and farmers who manage ant communities are also managing pests.”

This article has been produced by SciDev.Net’s South-East Asia & Pacific desk.

Link to abstract in Proceedings of the Royal Society
References
Proceedings of the Royal Society B doi: 10.1098/rspb.2013.2144 (2013)

http://www.scidev.net/global/agriculture/news/native-ants-help-indonesian-cocoa-yields-1.html

 

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Flickr/Bill and Melinda Gates Foundation

 

There was one unpleasant surprise in what was otherwise an invigorating and useful high-level discussion at the EU-Africa Business Forum this week (1 April) in Brussels, Belgium: a skewed focus on success and perhaps a reluctance to admit to failure.

The session was organised to draw up a set of core messages on how to get the business sector and public research organisations to work closer and better together on ensuring food security in Africa and Europe.

These were then fed into 4th EU-Africa Summit of Heads of State and Government of the European Union and African Union also taking place this week (2-3 April) in Brussels.

Following several ‘taster’ presentations that helped set the scene with successful examples, my task was to moderate a discussion that would identify both what works and what doesn’t work in making the two sectors more responsive to each other’s needs.
“It is time to look honestly and constructively at failures in the way we do things — in agricultural research and beyond.”

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Mićo Tatalović
“But despite a lively discussion involving most of the 50 or so delegates, and despite repeated calls to also hear examples of what worked less well, or not at all, we mostly only heard examples of success or thoughts on what ought to happen next.”

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Even a delegate who was involved in setting up a repository of examples of best practice aimed at farmers, when asked if we should also have a repository of ‘worst practice’ — things to definitely avoid, seemed unprepared for the question and unsure of how to answer it.

As in science, where in general only results that show something working well get reported, it seems that the participants preferred to highlight things that have worked well. From the launch of new small and medium size enterprises following on from EU Framework Programme 7’s research project in Egypt, to finding an innovative use for unpopular but productive mushroom farming in Rwanda, the success stories are many.

But as in science, our perspective and understanding are skewed if we never see the rest of the iceberg — the hypotheses that did not turn out to be correct — and don’t investigate why that was.

That things don’t always work the way we intended them to is evident from the various suggestions for new and different initiatives, such as innovative ways of financing agricultural research between the public and private sectors. If everything done so far was a success, why bother changing things — why not repeat past successes?

This lack of examples of less-successful initiatives limits our opportunity for learning.

Indeed, while it may be difficult to own up to having worked on project that just did not deliver, without recognising failure and understanding why it happened, we are unlikely to avoid it in future.

This is why SciDev.Net’s news recently started looking more proactively at past initiatives originally launched with high acclaim and high expectations, only to slowly fade from the media spotlight. These follow-up stories (‘whatever happened to…?’) offer valuable insights for others to learn from.

Recent examples include a 2008 MalariaEngage website designed to find a new way to crowdsource finding for malaria research in Africa; and Science for Humanity, which attempted to link up scientists and NGOs for better adoption of research in development work.

It is time to look honestly and constructively at failures in the way we do things — in agricultural research and beyond.

http://www.scidev.net/global/innovation/scidev-net-at-large/eu-africa-research-must-start-learning-from-failures.html

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Credit: University of Hull

PHYS.ORG

March 27,2014

A method of investigating whether aphid pests have been targeted by their gruesome enemies could shed new light on how farmland organisms interact, and potentially help protect important food crops.

http://phys.org/news/2014-03-exploring-natural-enemies-insect-pests.html#jCp

Aphids are capable of causing considerable damage to crops by sucking out the sweet sap, stunting growth and reducing yields. In some crops they also spread disease amongst plants, which can be even more destructive than their feeding behaviour. Farmers may spray their crops with costly insecticides several times a year to help reduce aphid numbers. However, scientists at the University of Hull are examining the beneficial role played by the natural enemies of these pests.
Dr Stéphane Derocles, Post-Doctoral Research Associate in the University of Hull’s Network Ecology Group, is one of the first to take a new approach to this field of research. The results of his study, published in the journal Molecular Ecology, shed light on the particularly grisly relationship between aphids and parasitic wasps.
Dr Derocles said: “In the past, the only way to identify whether an aphid was harbouring a parasitoid was to collect the aphids in the field, rear them in the lab and then observe if an adult wasp emerged. Identifying the precise species of wasp involved was exceptionally difficult, as they are tiny and appear very similar.
“Now we have a revolutionary new molecular technique that can not only tell us whether or not an aphid has a parasitoid, but also which species of parasitoid the aphid contains.”
Female parasitic wasps lay their eggs inside aphids, and then the developing parasitoid larva eats the host alive, before finally emerging from the dead aphid as an adult wasp. The larvae are ‘parasitoids’ and not ‘parasites’, because they always kill the aphid rather than just living inside it. Aphids which have died in this way appear swollen and brown with a papery appearance, and are known as ‘mummies’.
During his PhD in France, supervised by Professors Anne Le Ralec and Manuel Plantegenest at the ‘Agrocampus Ouest’ research institute, Dr Derocles collected more than 530 aphids from field crops, and a further 2,097 aphids from field margins (the strips of grass and wildflowers found around the edges of fields). He was interested to see if the field margins acted as a ‘reservoir’ for the beneficial parasitoids; therefore helping to control aphid numbers in the crop.

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By Jan Suszkiw
February 13, 2014

ARS molecular biologist Yan Zhao (left) observes as visiting scientist Wei Wu pretreats a tomato plant with salicylic acid to test its effectiveness against phytoplasma bacterial infections: Click here for photo caption.
ARS molecular biologist Yan Zhao (left) observes as visiting scientist Wei Wu pretreats a tomato plant with salicylic acid to test its effectiveness against phytoplasma bacterial infections.
(D3105-1)

Willow trees are well-known sources of salicylic acid, and for thousands of years, humans have extracted the compound from the tree’s bark to alleviate minor pain, fever, and inflammation. 

Now, salicylic acid may also offer relief to crop plants by priming their defenses against a microbial menace known as “potato purple top phytoplasma.” Outbreaks of the cell-wall-less bacterium in the fertile Columbia Basin region of the Pacific Northwest in 2002 and subsequent years inflicted severe yield and quality losses on potato crops. The Agricultural Research Service identified an insect accomplice—the beet leafhopper, which transmits the phytoplasma to plants while feeding. 

Carefully timed insecticide applications can deter such feeding. But once infected, a plant cannot be cured. Now, a promising lead has emerged. An ARS-University of Maryland team has found evidence that pretreating tomato plants, a relative of potato, with salicylic acid can prevent phytoplasma infections or at least diminish their severity.

Treating crops with salicylic acid to help them fend off bacteria, fungi, and viruses isn’t new, but there are no published studies demonstrating its potential in preventing diseases caused by phytoplasmas. 

Close-up of tomato leaves sprayed with the salicylic acid pretreatment: Click here for photo caption.
Close-up of tomato leaves sprayed with the salicylic acid pretreatment.
(D3106-1)

Wei Wu, a visiting scientist, investigated salicylic acid’s effects, together with molecular biologist Yan Zhao and others at ARS’s Molecular Plant Pathology Laboratory in Beltsville, Maryland. “This work reached new frontiers by demonstrating that plants could be beneficially treated even before they become infected and by quantifying gene activity underlying salicylic acid’s preventive role,” according to Robert E. Davis, the lab’s research leader. 

For the study, published in the July 2012 Annals of Applied Biology, the team applied two salicylic acid treatments to potted tomato seedlings. The first application was via a spray solution 4 weeks after the seedlings were planted. The second was via a root drench 2 days before phytoplasma-infected scions were grafted onto the plants’ stems to induce disease. A control group of plants was not treated. 

In addition to visually inspecting the plants for disease symptoms, the team analyzed leaf samples for the phytoplasma’s unique DNA fingerprint, which turned up in 94 percent of samples from untreated plants but in only 47 percent of treated ones. Moreover, symptoms in the treated group were far milder than in untreated plants. In fact, analysis of mildly infected treated plants revealed phytoplasma levels 300 times below those of untreated plants, meaning that the salicylic acid treatment must have suppressed pathogen multiplication. Significantly, the remaining 53 percent of treated plants were symptom- and pathogen-free 40 days after exposure to the infected scions. 

Researchers credit salicylic acid with triggering “systemic acquired resistance,” a state of general readiness against microbial or insect attack. Using quantitative polymerase chain reaction procedures, the team also identified three regulatory defense genes whose activity was higher in treated plants than in untreated ones. 

Why salicylic acid had this effect isn’t known. Other questions remain as well, including how treated plants will fare under field conditions. Nonetheless, such investigations could set the stage for providing growers of potato, tomato, and other susceptible crops some insurance against phytoplasmas in outbreak-prone regions.—By Jan Suszkiw, Agricultural Research Service Information Staff. 

This research is part of Plant Diseases, an ARS national program (#303) described at www.nps.ars.usda.gov.

Yan Zhao is with the USDA-ARS Molecular Plant Pathology Laboratory, 10300 Baltimore Ave., Beltsville, MD 20705-2350; (301) 504-6202.

Aspirin-Like Compound Primes Plant Defense Against Pathogens was published in the February 2014 issue of Agricultural Research magazine.

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From: KCUR 89.3FM Kansas City Public Media

Part of the npr digital network

New Crops Could Kill Insects By Targeting Their Genes

Credit Grant Gerlock / Harvest Public Media
Southern corn rootworm beetles eat corn laced with RNA in a lab at the University of Nebraska Lincoln. Scientists want to know how long it takes for rootworms to evolve resistance to RNA-interference technology.

With rootworms building resistance to genetically modified corn that makes its own pesticide, seed companies are working on new crops that target the insects’ genes. But some worry about unintended consequences when the technology moves from the lab to the field.

Rootworms are a constant nemesis of farmers in Nebraska and across the Midwest. Their larvae feed on the roots of corn plants. A decade ago, researchers developed Bt corn – corn genetically modified to produce a protein that kills the bugs, allowing farmers to back off chemical pesticides. But like every other pesticide that’s been tried against rootworms, the effectiveness of Bt corn is beginning to wear off, leading farmers across the Corn Belt to go back to chemicals that can be harmful to humans and wildlife.

Seed companies are preparing a new solution: RNA-interference, sometimes called gene silencing. Researchers using the technology introduce a strand of RNA that essentially stops an organism ingesting the molecule from expressing a certain gene.

Genes are expressed through RNA that are transcribed from DNA. But if you introduce a piece of interfering RNA, a gene can be suppressed. RNA-interference, or RNAi, is a natural way plants and animals fight off viruses, but scientists use it as a genetic on/off switch to study and manipulate plants.

Tom Clemente, a researcher in plant biotechnology at the University of Nebraska Lincoln, says RNAi was discovered in plants when researchers were trying to make flowers darker.

“They were trying to make a darker, purple flower and they were getting white flowers,” Clemente said. “They were trying to make more of this protein and they were making zero of the protein.”

Now, RNAi is being studied to treat human diseases from cancer to high cholesterol.RNAi crops are already in the field.

“The classic example is for virus resistance,” Clemente said. “In the state of Hawaii the entire papaya population is papaya ringspot virus (resistant) and it is a form of RNAi that provides that resistance.”

But corn could be the first crop to attack an invading insect with RNA. For instance,Monsanto hopes to commercialize rootworm resistant corn with RNAi by the end of the decade. When a rootworm eats the corn roots, it would ingest interfering RNA that would silence a gene the rootworm can’t live without.

“It blocks expression of that particular gene – no other gene – and impedes the life cycle of that rootworm,” Clemente said.

But Jon Lundgren, an entomologist at a USDA research lab in Brookings, S.D., says regulators should evaluate RNAi crops with caution. He is looking at whether RNAi aimed at one insect could have off-target effects on other insects, like bees or butterflies.

“Where else in the genome is going to be silenced inadvertently, and what effects is that going to have on the function of our natural biological systems?” Lundgren asked.

When one gene is silenced by interfering RNA, Lundgren says, sometimes a completely unrelated gene is altered in unpredictable ways, and that needs more consideration before these crops move from the lab to the field.

“Our really poor knowledge of genomes within most organisms, nearly all organisms, really begs the question of how we’re going to predict all of these potential effects,” Lundgren said.

That question goes to the Environmental Protection Agency. At a meeting in January, scientists from around the world will advise the EPA on how to assess the potential risks of RNAi crops.

For his part, Tom Clemente doesn’t believe the technology warrants extra scrutiny.

“You can dial it in to be very specific for a gene in a particular organism,” Clemente said. “Now, we can never say with a straight face that would mitigate any collateral damage in any other organism. But you can mitigate that probability to a very, very small number.”

Clemente says, when paired with Bt in corn, RNAi would give farmers a more durable weapon against rootworms. What regulators may want to know is if they can be sure it’s safe for the other bugs that call a cornfield home.

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Flikr/Kettema Yilma, ILRI,

SciDev

Speed read

  • Enset, a banana-like crop, supports livelihoods of 20 million Ethiopian farmers
  • A US$2.59 million project aims to create disease-resistant varieties of the crop
  • An expert welcomes the project and says other neglected crops should be targeted

ADDIS ABABA] A research project for developing varieties of enset, a traditional Ethiopian crop which resembles the banana plant, resistant to the deadly bacterial wilt disease has been launched. 
 
The project launched last month (16 December) in Addis Ababa, Ethiopia, is expected to address the perennial problem of the bacterial wilt disease that has remained a nightmare for scientists and farmers in the country.
 
The disease is caused by the bacterium Xanthomonas campestris pv.musacearum, and results in total crop wilt.

“Bacterial wilt is the major threat to enset, which supports the livelihoods of nearly 20 million smallholder farmers.”

Adugna Wakjira, Ethiopian Institute of Agricultural Research (EIAR)

 
Adugna Wakjira, the deputy director of the Ethiopian Institute of Agricultural Research (EIAR), tellsSciDev.Net: “Bacterial wilt is the major threat to enset, which supports the livelihoods of nearly 20 million smallholder farmers,” adding that lack of research capacity has partly contributed to inability to control the disease.   
 
Wakjira explains: “Since the disease is contagious, the farmers have been washing their tools such as knives, digging hoes and their hands when they come in touch with the crop to avoid passing the disease over to other enset plants”.
 
But these, he says, have little success, and the new varieties will completely replace the “sanitary measures”.
 
According to Wakjira, the crop is tolerant to drought and can cushion smallholder farmers against the effects of climate change.
 
Leena Tripathi, plant biotechnologist at the International Institute of Tropical Agriculture (IITA), Kenya, who will lead the project, says IITA scientists have made major strides in banana transformation to develop varieties resistant to the disease using genes from sweet pepper.
 
 “We will have one PhD student working on the project, which will be used to assist policymakers to formulate favourable policy to guidebiotechnology research in the country,” she says.
 
The project, a partnership between IITA, EIAR and Biosciences eastern and central Africa– International Livestock Research Institute (BecA-ILRI) Hub, will also help build Ethiopia’s human and infrastructure capacity to conduct biotechnology research on enset.
 
The Kenya-based BecA-ILRI will provide tools, technologies and chemicals to be used in the project.
 
The Bill & Melinda Gates Foundation is funding the four-year project for US$2.59 million.
 
Skills learnt from the project will be used to handle similar problems in wheat, rice and potatoes in Ethiopia, according to Wakjira.
 
“[The project] will be an avenue for our scientist[s] to hone their skills in biotechnology research to solve other problems affecting crops,” says Wakjira
 
Maurice Bolo, the director of Nairobi-based Scinnovent Centre, which focuses on science and innovation, tells SciDev.Net that using modern biotechnology tools to improve enset in Ethiopia must be seen within the broader context of other traditional African crops that have long been neglected by research but which support millions of livelihoods in Africa.
 
“[That] funding agencies and international research organisations are beginning to focus on such neglected crops is most welcome,” he says.
 
This article has been produced by SciDev.Net’s Sub-Saharan Africa desk.

http://www.scidev.net/sub-saharan-africa/farming/news/scientists-to-create-disease-resistant-ethiopian-enset.html
 

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Dow AgroSciences Advancing Novel Insect-Resistant Soybean Trait

First to Express Two Bt Proteins, Will Provide Broadest Pest-Control Offering on Market

From the Wall Street Journal

INDIANAPOLIS--(BUSINESS WIRE)--October 04, 2013--

Soybean farmers can look forward to a new solution to protect their crops thanks to a novel insect-resistant trait being developed by Dow AgroSciences. Dow AgroSciences LLC, a wholly-owned subsidiary of The Dow Chemical Company (NYSE: DOW) announces it is advancing an insect-resistant trait that, when commercialized, will provide soybean farmers with the broadest spectrum for insect control against lepidopteran pests. The company’s insect-resistant soybean trait is the first to be submitted for approvals that expresses two Bt proteins. This will provide broader in-plant protection of lepidopteran pests, as well as improve sustainability of the technology compared to other soybean technologies being advanced in the market with only one Bt protein. Extensive research has shown that the company’s trait provides broad in-plant protection against lepidopteran pests such as fall armyworm (Spodoptera frugiperda), soybean looper (Pseudoplusia includens), velvetbean caterpillar (Anticarsia gemmatalis), soybean podworm (Helicoverpa gelotopoeon), and tobacco budworm (Heliothis virescens) as well as Rachiplusia nu.

Submitted to regulatory authorities for approval in key soybean countries as part of the global authorization process, the trait is initially targeted for commercialization in South America. Brazil represents the largest opportunity where insect pressure results in significant yield loss every year. Argentina soybean farmers also face significant impact to their soybean yields due to insects. The company plans to broadly licen e the technology to regional seed companies in these countries to provide wide access for farmers.

Read more at: http://online.wsj.com/article/PR-CO-20131004-904809.html

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From Plantwise
http://blog.plantwise.org/2013/09/27/new-strategy-required-for-delaying-insect-resistance-to-bt-crops/

via Grahame Jackson:  pestnet@yahoogroups.com

September 27, 2013 by Claire Curry

Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)

Kenyan farmer Mary Ngare in her maize field damaged by stem borers © CIMMYT (CC BY-NC-SA)

Transgenic Bt crops have been grown around the world since the 1990s and have contributed to increased yields by controlling agricultural pests. Due to the importance of this technology, there has been continuous study into the development of resistance to Bt crops and how best to avoid this happening. A recent investigation into the rapid spread of Bt resistance in South Africa has revealed one of the more surprising discoveries to date, that the maize stalk borer (Busseola fusca) has evolved Bt maize resistance inherited as a dominant trait for the first time. This has significant impacts on the management of Bt crops, as current methods for sustaining susceptibility rely on the recessive inheritance of Bt resistance.

The first report of the resistance of maize stalk borer to Bt maize was in 2007 but for the majority of Bt maize fields resistance is not a problem. Methods for delaying resistance have been successful, keeping levels of susceptibility high. The method currently in use is the “high dose/refuge” insect resistance management (IRM) strategy, where susceptible insects can survive and breed in non-Bt refuges. This method relies on resistance being conferred by a recessive gene, so that when a susceptible pest mates with a resistant pest, the offspring are susceptible (see table). The high dose part of the name refers to the level of toxin the plant is producing. The toxin level must be sufficiently high to kill the Rr offspring, because if two Rr individuals mate, a quarter of their offspring will be rr – resistant individuals.

Inheritance of recessive resistance, where the recessive gene ‘r’ confers resistance and the dominant gene ‘R’ confers susceptibility

However, this method may fall down when dealing with non-recessive resistance inheritance, like that observed in South Africa. The discovery of dominantly inherited resistance of the maize stalk borer to Bt maize has raised more questions and opened new areas for study. The closing paragraph of the Campagne et al. paper highlights the importance of employing IRM strategies that include cases of non-recessive resistance and the necessity to consider IRM and IPM (integrated pest management) strategies, such as parasitic wasps, together. It is also possible that in the shorter term farmers in South Africa may have to move from the single toxin Bt maize they have been growing, to a double toxin variety to keep stalk borer numbers down.

Bt maize explained
Bt maize is one of the most widely grown transgenic crops. The bacterium Bacillus thuringiensis (Bt) produces crystalline proteins (cry proteins) that are toxic to insects. These proteins have been used to control agricultural pests since the 1960s, when they were applied to the crops in a spray. Nowadays some crops are able to produce their own cry proteins as they have had the cry protein-producing gene from B. thuringiensis integrated into their own set of genes. Bt crops are popular with many farmers as they require less pesticide, resulting in economic, health and environmental benefits.
To find out more about Bt crops visit Nature’s website.

van Rensburg JBJ (2007) First report of field resistance by the stem borer, Busseola fusca (Fuller) to Bt-transgenic maize. South African Journal of Plant and Soil 24 (3) 147-151.
Campagne P, Kruger M, Pasquet R, Le Ru B, Van den Berg J (2013) Dominant Inheritance of Field-Evolved Resistance to Bt Corn in Busseola fusca. PLoS ONE 8 (7) e69675.

 

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Adoption Analysis and Impact Evaluation of Potato IPM in Ecuador

Carrion Yaguana, Vanessa Del Rocio
URI: http://hdl.handle.net/10919/23286 Date: 2013-07-02

Abstract:

There are several well-known negative side effects associated with pesticide use such as health problems and environmental pollution.  Integrated Pest Management (IPM) seeks to minimize pesticide use while reducing pest infestation to economically tolerable levels.  The introduction of IPM CRSP activities in Ecuador to institutionalize IPM methods focused on priority crops in the country. This study analyzes adoption and the economic impacts of IPM technologies on potato production in the province of Carchi. A model is estimated in which IPM adoption is discrete and ordered and pesticides expenditures are estimated as a function of education, farming experience, wealth, plot size and farmer being sick due to pesticide use for each level of IPM adoption. Results indicate that farmers who were exposed to certain IPM information sources increased adoption of IPM practices on potatoes, but farmers\' education and experience were not important factors in explaining IPM adoption. The calculated economic benefits in terms of aggregate cost savings per production cycle were $823,000.

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