Abstract: A method for determining the genotype of a gypsy moth is disclosed. This method begins with the steps of isolating genomic DNA from a candidate gypsy moth, exposing that DNA to an oligonucleotide primer selected from the group consisting of SEQ ID NOs:3, 4, 5, 6, 7 or the complement thereof and sequences sufficiently similar to SEQ ID NOs:4 and 5 or the complement thereof under conditions permitting amplification of the genomic DNA, and comparing the amplified DNA with amplified DNA produced by control samples. A genotype identity is assigned to the candidate moth according to which control sample has amplified fragments similar to those in the candidate sample. A method for obtaining DNA primers for determining the genotype of candidate moths is also disclosed.