Cauliflower mosaic virus (CaMV)
Hosts
CaMV infects many vegetable brassica crops including broccoli, Brussels sprouts, cabbage and cauliflower but does not infect non-brassica crops. It also infects some brassicaceous weeds such as wild radish which act as infection reservoirs.
Distribution
CaMV is found in temperate regions worldwide. It infects vegetable brassica and canola crops in Western Australia.
Symptoms
In cauliflower, symptoms on leaves can be initially hard to see in the field. Later in the season, mosaic patterns are easier to observe and veinal chlorosis (vein clearing) becomes prominent (Figure 3), plants are stunted and heads are small and poor quality. In other vegetable brassicas, CaMV-infected plants often do not show any symptoms.
Spread
CaMV is spread by a number of different aphid species such as the green peach and cabbage aphids, both of which colonise vegetable brassicas. As with TuMV, the virus is picked up from infected crop plants or weeds and spread to healthy brassica crop plants.