Biology Reference
In-Depth Information
with small, round, or heart-shaped leaves. Use
certified seed potatoes.
Prune Dwarf Ilarvirus
On prune, plum, cherry and peach. Leaves are
small, narrow, rugose, distorted, glazed. Inter-
nodes are short, but some branches escape and
appear normal. Blossoms are numerous, but
mature fruits few; pistils are aborted, petals
narrowed. Most injurious to Italian prune, symp-
tomless in Bradshaw and damson plums. Trans-
mission by grafting and budding.
Potato Yellow Dwarf
Nucleorhabdovirus
Formerly causing heavy losses in Northeast but
now mostly controlled by seed certification.
Potato leaves are rolled and yellowed; the plant
is dwarfed with split stems showing rusty flecks.
Transmission is by clover leafhoppers;
overwintering hosts are ground cherry, oxeye
daisy, vinca and other plants.
Prunus Necrotic Ringspot Ilarvirus
Potato Yellow Spot
Very common in sweet cherry and plum
orchards, worldwide. Its natural hosts are species
from
Prunus, Rosa, Humulus
and
Cucumis
. Ear-
lier virus was described as Plum Line Pattern,
Peach Ringspot, Prunus Ringspot, Red Currant
Necrotic Ringspot, Rose Chlorotic Mottle, Rose
Line Pattern, Rose Vein Banding and Sour
Cherry Necrotic Ringspot. Virus is transmitted
by grafting, by seeds and by pollen to seeds and
to the pollinated plants.
Reported from Maine, mostly on Katahdin vari-
ety. Spots are small, circular, bright yellow,
chiefly on lower leaves.
Primrose Mosaic
Plants are chlorotic, stunted, rugose, with
upward, sometimes downward, cupping of
leaves. Petioles and peduncles are shortened;
flowers are white-streaked; leaves are coarsely
mottled yellow-green, with green islands; tips of
leaves are narrowed. No insect vector is known.
Quail Pea Mosaic Comovirus
Caused mosaics on
Streptostyles helvola
as well
as on soybean and common bean plants.
Privet Ring Spot
Radish Mosaic Comovirus
Reported on privet in Texas. Leaves are smaller,
lighter green, drop early.
Chlorotic spotting and mottling of foliage; plants
not stunted.
Prune (Standard) Constricting Mosaic
Ranunculus Mottle Potyvirus
Spots are concentrated in a band across tip of the
leaf; this area is killed, and all tissue except the
midvein drops out.
Caused foliar mottling and distortion on
Ranun-
culus asiaticus
plants.
Prune Diamond Canker
Raspberry Alpha Leaf Curl Luteovirus
ym toms rd ly n r h
prune -diamond or oval excrescences on second-
ary branches, often excess sprouts from body
of tree.
Common on red raspberry. Veins are retarded in
growth, causing downward curling and crinkling
of leaves. Foliage is dark green, but bronzed in
