Study finds new insecticides don't degrade as efficiently as previously thought

Genetic engineers are developing new types of insecticides based on dsRNA (double-stranded RNA). They are intended to work by reducing (“silencing”) the expression of target genes of insect pests through a mechanism called RNA interference (RNAi), resulting in the death of the pests.

They can either be genetically engineered into the plant or sprayed on.

However, scientists have not understood what happens to these insecticides once they contact the soil. Do they break down easily or persist, potentially affecting soil organisms?

A new study by researchers at Washington University in St Louis, USA and ETH Zurich, Switzerland, gives some answers.

The researchers looked at the fate of dsRNA in different types of soil. They found that in some soils, enzymes in the soil can break down the insecticide and microbes can eat it, meaning that the dsRNA insecticide degrades.