Potato Leafroll Virus - Disease Cycle

Disease Cycle

PLRV can be introduced to potatoes by planting infected seeds or by insect vectors. The green peach aphid (Myzus persicae) is the primary vector of PLRV. Aphids acquire the virus by feeding on infected plants. The infected phloem is taken up through the aphid proboscis into the digestive system. The virus then crosses the membrane of the gut and enters the hemocoel where it then can cross the membrane into the salivary glands. This process takes several hours after which time the aphid will continue to transmit the virus for its remaining life. This process is known as persistent transmission. In temperate regions, the green peach aphid is able to persist through the winter by laying eggs in woody species of the genus Prunus. Eggs hatch in early spring and early instar aphids feed on tree phloem until summer when they switch to more preferred herbacous hosts including agricultural crops. During this time the green peach aphid can transmit PLRV present in weeds of the family Solanaceae to potatoes and other crops. Potato plants infected with PLRV will produced infected tubers. If infected tubers are planted they will give rise to infected plants. Aphids can also spread PLRV to tubers in storage, especially after they sprout. Winged aphids can be carried several hundred kilometers by wind currents allowing for wide spread infection.