We have isolated based on reverse genome hybridization, and sequenced a DNA clone, pNZE25, from a partial genomic library of the Asian rice gall midge Orseolia oryzae (Wood-Mason) (O.o.). Clone pNZE25 is highly A+T rich (67%), lacks any open reading frame and does not display homology to sequences in GenBank. Clone pNZE25 detects a 120-bp repeat in the O.o. genome, as seen from the generation of a 120-bp ladder after Southern analysis of HinfI-digested genomic DNA. When used to probe O.o. genomic DNA digested with DraI, HaeIII or AluI, pNZE25 generates individual specific DNA fingerprints on target DNA isolated from gall midge biotypes collected from different parts of India.