Farmers in Australia apply between 80 and 200 kg N ba-1 to cotton, but only part of this nitrogen is taken up and used by the crop, and the remainder is lost :from the plantsoil system.

Verticillium wilt of cotton is caused by a fungus (Verticillium dahliae) that infects the host plant via the roots and colonises the vascular system.

Traditional plant breeding techniques have had a major impact on the Australian cotton industry through the production of the widely successful CSIRO varieties Siokra and Sicala.

A disease can only occur when a virulent pathogen contacts a susceptible host under favourable environmental conditions. The incidence and severity of a disease reflects the occurence of these three factors.

The use of aircraft in agriculture in recent years has provoked much attention.