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

With current Australian cotton production around 1.25 million bales this equates to C.R.C. research expenditure of A$3.2 to 3.5 million per year - allowing for reserves, administration, etc. These C.R.C.

The fungal disease Verticillium wilt has been of sporadic importance in irrigated cotton for many years.

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.

To understand, and predict, Heliothis dynamics on cotton, along with changes in resistance levels, we must understand their dynamics on other hosts and the patterns of movement from these to cotton.