Double stranded RNA (dsRNA) can be used to suppress the production of proteins in organisms. Cells produce proteins by a complex apparatus that gets the code for the sequence of amino acids in a protein from messenger RNA (mRNA). dsRNA can be designed to bind to specific mRNA. When the amount of an mRNA is reduced, the amount of protein coded by that mRNA is also reduced. When ingested by an insect, dsRNA is effective at suppressing insect mRNA and protein. If the protein is important to the insect, consuming dsRNA can kill the insect.
One way to “feed” dsRNA to insects is to genetically modify the plants it eats. Many modification have been unsuccessful because plants will actively degrade dsRNA. Zhang and colleagues* have recently found that a plant will not rapidly degrade dsRNA if it is produced in chloroplasts. They transformed the chloroplasts of potato plants to produce dsRNA that inhibits production of Actin in Colorado Potato Beetle. Feeding these genetically altered plants to Colorado Potato Beetle greatly reduced survival of the beetle.
*Jiang Zhang, Sher Afzal Khan, Claudia Hasse, Stephanie Ruf, David G. Heckel, Ralph Bock. 2015. Full crop protection from an insect pest by expression of long double-stranded RNAs in plastids. Science 27 February 2015: 347: 991-994