CRUCIFEROUS VEGETABLES - VIRUSES

Host range: CaMV and TYMV are restricted to the family Cruciferaceae only but TuMV has broader host range including poppy and some other species.

Occurrence and importance: TuMV and CaMV occur time to time on some plants in crops but TYMV can heavily infect mainly Chinese cabbage. Infected plants either don´t form edible parts of poor quality, if at all. These viruses are not very common, but emerging/new pests with piercing-sucking mouthparts that are vectors of viral diseases, may result in serious damage.

Symptoms: Typical symptoms are mosaics, vein clearing, leaf distortions and plant stunting. For the layman it is difficult to discriminate the symptoms of these viruses each from others with the exception of those of TYMV on Chinese cabbage where a severe yellow mosaic occurs.

Transmission & Epidemiology: All viruses can overwinter on winter rape and cruciferous weeds, as well as on transplants intended for planting for seed production. TYMV is also weakly seed transmissible. TuMV and CaMV are transmitted by aphids (Brevicoryne brassiceae, Myzus persiceae) in a nonpersistent manner, TYMV is transmitted by flea beetles.

 

Control:

• elimination of the weeds that act as virus reservoirs, also aphids, flea-beetles, and infected plants (inoculum sources)
• maintain healthy seed crops (for TYMV)
• isolation of main crop from seed crops
• covering smaller plots by white net as protection against vectors.