Monsanto develops genetic pest control sprays

Agricultural biotech giant Monsanto is developing “genetic sprays” that use RNA interference – known as RNAi – to combat pests and enhance crops rather than developing GMO crops.

The sprays will control weeds and insect pests by temporarily altering their genetics, MIT Technology Review reports. RNAi enables genes to be switched off without making permanent genetic changes.

Monsanto sees the RNAi sprays as an alternative to developing new genetically engineered crops, and could also be used to introduce beneficial traits like drought resistance into plants.

The discovery of RNA interference earned two academics a Nobel Prize in 2006 and set off a scramble to create drugs that block disease-causing genes. Using this same technology, Monsanto now thinks it has hit on an alternative to conventional genetically modified organisms, or GMOs. It can already kill bugs by getting them to eat leaves coated with specially designed RNA. And if the company succeeds in developing sprays that penetrate plant cells, as it’s attempting to, it could block certain plant genes, too. Imagine a spray that causes tomatoes to taste better or helps plants survive a drought.


Dr. Jeffrey Scott, a professor in Department of Entomology at Cornell University welcomed the development.

“The single biggest problem with conventional insecticides is their effects on non-target organisms,” he said. 

“Using RNA interference to kill pests through sprays of double stranded RNA (dsRNA) has the potential to be species specific. This individual targeting can be achieved because genes vary enough between different species that specific dsRNA could only affect the desired pest.”

But he warned that targeting single species is not guaranteed.

“For example, in a recent paper we showed that a spray of dsRNA from a house fly could kill Colorado Potato Beetles,” he said.

“In some cases, conventional insecticides are used because they kill multiple insect pests.  Thus, an insecticide that targets only one species has lots of benefits, but might not be cost effective. Then there is the issue that insects always find a way to evolve resistance, and harnessing RNAi will be no different.  The relative speed with which resistance will happen is a wide open question.”

Dr. Allison Snow, Professor of Evolution, Ecology, and Organismal Biology at Ohio State University said that the technology was promising but very new.

“It may take awhile before biotech companies figure out which RNAi sprays are going to work well enough to be commercially viable, but the field is moving quickly,” she said.

“Like GMOs, these genetic sprays will need to be evaluated for health and environmental effects on a case-by-case basis.  It doesn’t make sense to group them together and conclude that all of them are either safe or risky.”

The MIT Technology Review says that other companies are working in the same field.

Monsanto isn’t the only one working on genetic sprays. Other large agricultural biotech companies, including Bayer and Syngenta, are also investigating the technology. The appeal is that it offers control over genes without modifying a plant’s genome—that is, without creating a GMO.

The companies hope that by do that, they can sidestep  much of the controversy that surrounds agricultural biotechnology. 

You can find previous Cosmos coverage of GMO crops and agricultural science here.


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