Beneficial bugs can co-exist with Bt crops, new studies show

Geocoris punctipes feeding on an unidentified Homopteran. Credit: Russ Ottens, University of Georgia,

Genetically modified, insect-resistant Bt crops do not have harmful effects on beneficial bugs in farmers’ fields, two new scientific papers published this week have shown.

These add to the environmental case for GM technology, because by controlling crop pests in a very targeted way using insecticidal proteins (Bt) expressed in plant tissues, farmers can reduce broad-spectrum insecticide sprays and thus protect wider farm-scale biodiversity.

In the first paper, an international team led by Chinese scientists reported that after conducting field experiments lasting several years, they found no significant differences in the spider communities populating Bt rice fields as compared to a non-Bt control rice crop.

On the other hand, as expected, when both types of fields were treated with chemical insecticide sprays, populations of spiders were significantly reduced. Spiders play an important role in controlling agricultural pests.

The scientists write in Plant Biotechnology Journal: “These results suggest that Bt rice has no long term impacts on the structure of the spider community, whilst chemical insecticides exhibit negative impacts.”

The second paper looked at the potential impact of Bt maize in Brazil on a tiny parasitic wasp called Trichogramma pretiosum. This insect occurs naturally in the country, and because it feeds on the eggs of fall armyworm moths and other agricultural pests it is highly valued as a biocontrol agent by farmers.

If the insecticidal proteins expressed inside Bt maize crops — which have proven extremely effective in targeting lepidopteran pests — were also harming beneficial insects like T. pretiosum, that would be a serious concern for farmers and ecologists alike.

Fortunately, that appears not to be the case. As reported by Brazilian scientists in the journal Biocontrol Science and Technology: “All Bt hybrids [of maize] evaluated were harmless to T. pretiosum.”

The authors add: “All the Bt proteins evaluated in this study target lepidopterans specifically, and do not have deleterious effects on T. pretiosum, even when extreme exposures produced under laboratory conditions have been tested.”

The findings of both papers are important because they strengthen the case for the use of Bt crops in integrated pest management (IPM) farming approaches. One of the techniques of IPM is to nurture populations of natural enemies of insect pests — such as lacewings, wasps, ladybugs and spiders — to reduce the necessity for chemical sprays.

These studies, which add to a widespread consensus that Bt crops do not harm non-target organisms, mean that Bt crops can be used as part of a broad array of IPM techniques. This is important also to try to forestall the evolution of resistance to Bt proteins among the pest species.

One recent review paper concluded: “In summary, the available body of literature provides evidence that insecticidal proteins used in commercialized Bt crops cause no direct, adverse effects on non-target species outside the order (i.e., Lepidoptera for Cry1 and Cry2 proteins) or the family (i.e. Coleoptera, Chrysomelidae for Cry3 proteins) of the target pest(s).”

Good news for spiders and wasps is also good news for farmers and the environment, it seems.

Read the original article

Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
can you boost your immune system to prevent coronavirus spread x

Video: How to boost your immune system to guard against COVID and other illnesses

Scientists have recently developed ways to measure your immune age. Fortunately, it turns out your immune age can go down ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
globalmethanebudget globalcarbonproject cropped x

Infographic: Cows cause climate change? Agriculture scientist says ‘belching bovines’ get too much blame

A recent interview by Caroline Stocks, a UK journalist who writes about food, agriculture and the environment, of air quality ...
organic hillside sweet corn x

Organic v conventional using GMOs: Which is the more sustainable farming?

Many consumers spend more for organic food to avoid genetically modified products in part because they believe that “industrial agriculture” ...
benjamin franklin x

Are most GMO safety studies funded by industry?

The assertion that biotech companies do the research and the government just signs off on it is false ...
gmo corn field x

Do GMO Bt (insect-resistant) crops pose a threat to human health or the environment?

Bt is a bacterium found organically in the soil. It is extremely effective in repelling or killing target insects but ...

Environmental Working Group: EWG challenges safety of GMOs, food pesticide residues

Known by some as the "Environmental Worrying Group," EWG lobbies for tighter GMO legislation and famously puts out annual "dirty dozen" list of fruits and ...
m hansen

Michael Hansen: Architect of Consumers Union ongoing anti-GMO campaign

Michael K. Hansen (born 1956) is thought by critics to be the prime mover behind the ongoing campaign against agricultural biotechnology at Consumer Reports. He is an ...
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend