Potatoes are susceptible to a number of diseases as is historically illustrated by the Great Potato Famine of 1845-1849. While this famine was caused by late blight, a disease that destroys not only the foliage but the edible tuber, a bit more benign disease, curly top virus in potatoes, can still wreak some havoc in the potato garden. What causes potato curly top virus? Read on to find out as well as the symptoms of potatoes with curly top and about curly top management.
What Causes Potato Curly Top Virus?
The pathogen is transmitted by the beet leafhopper, Curculifer tenellus. As its name indicates, the leafhopper pest transmits the disease to a number of crops and weeds, including:
Both the leafhopper and virus survive on a wide range of weeds and wild plants. The leafhopper ingests cell sap, which contains the virus, which then incubates in the leafhopper for 4-21 hours before being transmitted. The disease is then transported through the plant’s tissues.
Symptoms of Curly Top Virus in Potatoes
Potatoes with curly top often have dwarfed yellow, rolled or cupped up leaves. Foliage becomes mottled yellow and leaflets tend to roll up. Veins of outer leaflets remain green but the rest of the leaflet turns yellow. Infected tubers are often small and sometimes elongated, and aerial tubers may form.
Symptoms of curly top in potatoes appear after 24 hours with hot temperatures and more slowly in cooler temps.
Curly Top Management
Curly top is transmitted in potato seed pieces, so one method to control the disease is to use certified seed potatoes.
An obvious control method would be to control the leafhopper population but, unfortunately, this has proven to be difficult as insecticides are not effective. Commercial growers instead resort to mesh mechanical barriers over susceptible plants. A more realistic approach to curbing the insects is to control the weed population, particularly those weeds that leafhoppers find most appealing, such as Russian thistle.
Once symptoms appear, it is best to pull the potato plant(s) out and destroy it/them.