Distribution of southern sting nematode, Ibipora lolii (Nematoda: Belonolaimidae), on turfgrass in Australia and its taxonomic relationship to other belonolaimids

Abstract

Molecular evidence from sequences of three regions of ribosomal DNA (partial SSU, ITS-1, 5.8S and ITS-2, and D2/D3 expansion segments of LSU) is presented to show that the two belonolaimids described from turfgrass in Australia (Ibipora lolii and Morulaimus gigas) are identical. Morulaimus gigas is therefore considered a junior synonym of I. lolii. The decision to place the nematode in Ibipora rather than Morulaimus is supported by molecular studies which showed that I. lolii is not closely related to Morulaimus or Carphodorus, two belonolaimid genera that are only found in Australia. Survey data are presented to show that I. lolii is widespread on turfgrass around Newcastle in New South Wales and in Perth, Western Australia, where the infested area is increasing rapidly, largely because the nematode is being spread in planting material. Ibipora lolii damages all turfgrass species but is particularly damaging to kikuyu grass (Pennisetum clandestinum), the main grass used for sporting fields and recreational areas in warm regions of Australia. Data from an experiment in pots also show that the nematode multiplies to damaging levels on sugarcane. Symptoms on grasses are similar to those caused by the sting nematode, Belonolaimus longicaudatus, in south-eastern USA, but because the two nematodes are taxonomically different, I. lolii is referred to as the southern sting nematode. Ibipora lolii was not found in surveys of natural vegetation on the east and west coasts of Australia, suggesting that it is an introduced species, possibly originating in South America or the Caribbean, where other Ibipora species are found.