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Genetic Sprays Use RNA Interference to Combat Pests

Monsanto is developing sprays to control weeds and insect pests by temporarily altering their genetics through RNA interference as an alternative to developing new GM crops, and could also be used to introduce traits like drought resistance.

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“The single biggest problem with conventional insecticides is their effects on non-target organisms. Using RNA interference (RNAi) 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.

“However, 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.

“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.

“Currently, using dsRNA sprays is limited to insects that eat the leaf. Insects like aphids that consume fluids from the leaf seem much less affected. Some species are just refractory to this technology and this includes several economically important Lepidoptera (caterpillars). There may be ways to use this technology against aphids and other refractory species, but we are only in the early stages.


The full text of this article can be purchased from Informit.