Despite having been considered for many years, application
of RNAi technology to give resistance to herbivorous
insects has only just been realised. Two recent papers have
described transgenic plants producing dsRNAs directed
against insect genes. These plants showed enhanced resistance
to the economically important agricultural pests cotton
bollworm (Helicoverpa armigera; Lepidoptera) and
Western corn rootworm (WCR; Diabrotica virgifera virgifera
LeConte; Coleoptera). The key to the success of this
approach is: (i) identification of a suitable insect target and
(ii) dsRNA delivery, which includes in planta expression of
dsRNA and delivery of sufficient amounts of intact dsRNA
for uptake by the insect. Although different approaches
were used for the generation of insect-resistant plants,
careful target selection was common to both (see Figure 2).