An isolated double stranded ribonucleotide molecule, defined as produced by preparing a recombinant polynucleotide molecule comprising a first and a second polynucleotide sequence, wherein the first polynucleotide sequence consists of an isolated polynucleotide molecule which encodes SEQ ID NO:23, wherein the second polynucleotide sequence is substantially the reverse complement of the first polynucleotide sequence such that the first and the second polynucleotide sequences hybridize when the recombinant polynucleotide molecule is transcribed into a ribonucleic acid molecule that forms the double stranded ribonucleotide molecule, wherein the double stranded ribonucleotide molecule inhibits the growth of a G. rostochiensis nematode.