Twisting by wind, fertilizer burn or insect feeding may have allowed entry of the fungus. The use of wind breaks, careful placement of solid fertilizer or 'fertigation' through irrigation, and control of insect damage should be of primary concern. Once damage is noted, there is little that can be done to reduce losses. It is distinct from bacterial speck, which is common on tomato but does not affect capsicum. A similar bacterial disease on cabbage and similar crops does not affect capsicum or tomato.
Affected leaves tend to fall readily.
The disease is seed borne and spreads readily in the crop under overhead irrigation. Bacterial spot is mainly seen in Carnarvon, where it can be very damaging. Various fungicides containing copper are registered for use against this disease. Of the viruses infecting capsicum, only CMV has been recorded in Western Australia. Symptoms include leaf mottling and narrowing, as well as fruit malformation and yellowing.