Biology Reference
In-Depth Information
spots, may wither and dry. Later growth is mot-
tled green and yellow with small chocolate brown
spots and dark brown streaks on stems; fruit has
brown greasy spots. The disease is more impor-
tant in greenhouses; workers should refrain from
handling tobacco or potatoes while working with
tomatoes.
Tritonia Mosaic
Mottling at base of young leaves.
Tulare Apple Mosaic Ilarvirus
Caused leaf chlorosis on
Corylus
and
Malus
sp., it
is transmitted only by mechanical inoculation.
Virus is related to Citrus Leaf Rugose Ilarvirus.
Tomato Top Necrosis Neopvirus
Occurs in Indiana, Missouri and Illinois. Virus is
very rare on tomato plantations. It is serologically
related to many nepoviruses.
Tulip Breaking Potyvirus
Due to Lily Latent Mosaic virus often present
with Tulip Color-adding virus. Broken tulips
appear wherever hybrids are grown. There is little
or no obvious effect on foliage and little interfer-
ence with growth, but there are marked color
patterns on the flowers; differences in named
broken varieties possibly due to the proportion
of color-breaking and color-adding viruses pre-
sent. Most pure white flowers do not change;
some turn pink or red. Pink and bright red flowers
have strong color changes; very dark tulips turn
even darker. There may be dark stripes due to
pigment intensification. Transmission is by
aphids, and roguing should take place early,
before insects are active. Broken varieties should
not be grown near those with solid colors.
Tomato Western Yellow Blight
Beet Curly Top Hybrigeminivirus.
▶
Tomato Yellow Leaf Curl Begomovirus
On tomato.
Tomato Yellow Net
¼
Tobacco Yellow
Net Luteovirus
Pronounced yellow necrosis of veins and vein-
lets. Transmission by the peach aphid.
Turnip Mosaic Potyvirus
Tomato Yellow Top ¼ Strain of Potato
Leafroll Luteovirus
Cabbage Black Ring Spot; Watercress Mottle;
Nasturtium Mosaic. On turnip, rutabaga, rape,
mustard, cabbage, collard, horse-radish, water-
cress, garden balsam, nasturtium, stock, lady's
slipper, impatien, safflower and sweet rocket.
Turnip shows a systemic chlorotic mottling with
crinkling, leaf distortion, stunting of plants. Cab-
bage has numerous small, black necrotic rings or
spots; cauliflower and broccoli have a diffuse
systematic mottling. Horse-radish has blotchy
mottling, necrotic rings, flecks, and streaks on
petioles and leaf veins. Variegated flowers appear
on nasturtium stock, wallflower and sweet rocket;
Leaflets small, curled, yellow; or purplish in cool
weather.
Tradescantia - Zebrina Potyvirus
Transmitted by aphids to
Tradescantia, Zebrina,
Commelina
and
Rhoeo
sp. plants on which it
caused mosaics, stuntings and malformation of
leaves.
