in the Gwydir Valley where the water resource has been over committed to such an extent that a full allocation of water will only be realized only SO years out of every 100 years.

I have to tell you now that I will not be presenting such a perspective.

One such form is biological control, which relies on the use of natural pathogens and parasites to control the pest species.

Nematodes are regarded as a major pest of cotton in many parts of the world. It has been claimed that "nematodes cause economic losses to cotton everywhere it is grown" (Watkins. 1981).

In recent times cotton growers have seen the need to adopt new land preparation practices. In the Macquarie Valley alone, only 35% of the 1987/88 cotton crop was prepared using conventional techniques.