CUCUMBER MOSAIC VIRUS

Host range: Muskmelon, watermelon, cucumber and squashes.

Distribution and importance: The virus is found worldwide but it is most common in temperate regions such as Europe. The virus generally induces a severe yield reduction mainly due to decreased fruit set. Yield losses are directly related to time of infection. The later the infection occurs, the less damage will be observed.

Symptoms and changeable diseases:

Plants can be infected at any stage of growth. When seedlings become infected they remain small, turn yellow, and die. Symptoms on older plants include dwarfing of plants, mottling, distortion, and downward curling leaves. Muskmelon fruit rarely shows symptoms but usually is off-color and bitter-tasting. Watermelons infected with the virus (Picture 22) usually show less stunting and mottling than muskmelons.

 

Disease cycle: The virus survives the winter in roots of susceptible plants, in greenhouses, and possibly in seeds of wild cucumbers. Aphids are the principle means of dissemination of the virus. The most efficient vectors are Myzus persicae and Aphis. Mosaic also can be transmitted by the cucumber beetle and by workers picking cucumbers. As aphids feed on virus-infected hosts, they become contaminated with the virus and subsequently spread it to healthy plants. The virus can be acquired by all installs within 5-10 sec, their ability to transmit declines after about 2 min and is usually lost within 2h.

Control: Most effective method of control of common mosaic on cucumber is planting resistant varieties. However, weed control around and within the planting is important, since the virus can survive in many weed plants. To reduce or delay spread is critical to remove infected plants when symptoms first appear