The invention involves combining a peptide toxin effective against insects, including but not limited to thrips, leaf hoppers, and beetles, with a transport peptide capable of facilitating transfer of the peptide toxin from the gut of an insect to the hemocoel. The combination can be effected by a fusion of genetic material encoding the peptide toxin and the transport peptide, such that expression of the genetic material fusion results in synthesis of a fusion protein combining the functions of both the toxin and the transport protein. Ingestion of the fusion protein by the sucking insect transfers the fusion protein into the insect's gut from which it is transferred into the hemocoel due to the functional activity of the transport peptide where the toxin exerts its toxic effect upon the insect. In a preferred embodiment, the invention is effective in control of such sucking insects as aphids, whiteflies and the like, and other vectors that transmit viruses in a circulative manner.