Abstract: Provided is a peptide, peptide multimer or fusion protein containing such peptide which binds to the gut of sap-sucking insects, e.g., aphids. When bound, this peptide inhibits the binding of targeted virus to the insect gut. When this peptide or tandem repeat peptide is expressed (or is expressed as part of a fusion protein) in the fluids of transgenic plants, it is taken up by the insect with the sap, binds to gut receptors and thereby inhibits transmission of the virus from plant to plant via the insect vector. Thus, the use of such transgenic plants blocks or reduces the transmission of the targeted virus and others which share the peptide binding site within the insect gut among plants susceptible to the virus and thereby reduces losses due to viral infection.

Abstract: 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.