Understanding the ecology of reniform nematodes in cotton

VSince the first detection in the Dawson/Callide region of Central Queensland in 2012, reniform nematode has become a serious concern for cotton growers and researchers as well. Although reniform is considered one of the major diseases of cotton in the US, it is still considered a minor problem in the Australian cotton industry due to the limited scientific studies of the epidemiology of reniform in the Australian cotton cropping system. This project had a number of objectives to address knowledge gaps and obtain data to understand how the reniform nematode is interacting with cotton plants in Australian soil so that we can improve the management practice. In this project, large numbers of cotton fields from both NSW and QLD have been monitored every season to confirm the presence or absence of plant-parasitic nematodes, and to provide an indication of possible nematode problems in the field. To understand the ecology of reniform nematode in Australian cotton, three glasshouse pot trials were conducted specifically to assess the vertical movement reniform nematodes in the vertisol soil, host/non-host suitability to different crops for reniform nematode, and effect of different reniform nematode population on growth and yield of different cotton varieties. The genetic diversity of the reniform populations found in different crops including cotton was compared to each other while it was also compared with international isolates. Additionally, three different field trials were conducted during this project period to investigate the effectiveness of seed treatment products (with nematicidal property) and a biological control agent to control the reniform nematode.