Natural vectors of phytoplasma to grapevine in Italy Flashcards
Nearctic and flavescence doree
Scaphoideus titanus
Palearctic and Bois Noir, Vergilbungskrankheit, Legno Nero
Hyalesthes obsoletus
What is flavescence doree
Phytoplasma disease
Scaphoideus is…(order..)
Hemiptera: Homoptera: Cicadellidae
(leaf hopper)
Scaphoideus titanus
The nymph of Scaphoideus Titanus with its distinctive two brown dots on the tip of the abdomen which is armed with spines
Where did scaphoideus come from?
The U.S.
Life cycle (5)
- One generation
- Overwintering as eggs in bark
- Eggs hatch from May to July
- Nymphs are very active and complete development through 5 nymphal instars
- Adults from July - October, females oviposit in August
Damage
The leafhopper itself isnt itself harmful to the plant, but is a vector for FD which is a phytoplasma disease (a quarantine pathogen and is incurable)
Transmittance of FD
Nymphs acquire phytoplasma on infected plants. There is a latency period of 28-35 days. Adults transmit on healthy plants
What are phytoplasmas?
They are a peculiar group of bacteria
Where does it reside in the plant?
Phloem bundles where they induce necrosis and hyperplastic tissue
FD Symptoms
Delay or lack of budburst.
FD Symptoms in Spring (3)
- Reduce growth of fruiting cane
- change in leaf color and curling of leaves
- Premature leaf fall
FD symptoms in Summer (2)
Failure to lignify and Dessication of inflorescences and grapes
Where can we look for nymphs for monitoring?
Basal leaves
Best color for attracting Scaphoideas
Yellow
How can we reduce vector population?
branches from winter pruning should be destroyed since they host leafhopper eggs.
What kind of site can be very bad and hold many instances of S. titanus?
Abandoned vineyards
Which plants can hold the entire lifecycle from egg to egg?
Vitis Labrusca and vitis riparia making it an oligophagous species
What is the control of this issue like in Italy?
It is completely mandatory usually 2-3 sprays are necessary in both conventional and organic farming
