Grapevine Leafroll

Question 0

Casual agent

Answer 0

GLRaV-3
Also 1 and 2
Ampelovirus
Closteroviridae

Question 1

What cause

Answer 1

Degeneration of vascular tissue
Delayed ripening
Reduced sugar
Reduce yield

Question 2

Disease epidemic traingle

Answer 2

Plant- vine
Virus-GLRaV3
Vector- mealybug

Question 3

Plant symptoms

Vitis vinifera

Answer 3

Obvious symptoms: autumn- blackberried cultivars-pinnotage/merlot
Green berries- chenin blanc,not chardonnay

Root stock: v berlanderie
V ripariaV rupestris

Question 4

Virus

Answer 4

Not mecahnically transmissible-phloem limited

Dont clean materials between harvest

Question 5

Resitricted to vitis good?

Answer 5

Yes dont worry about seed reservoirs

Question 6

Transmitted

Answer 6

Vegetative propagation: buds pruned and cleave buds,cut canes become new planting material

Grafting- callus of graft covered

Question 7

Vector

Answer 7

Mealy bugs- planococcus ficus
Soft scales

Virus transmitted semi persistently
Loose skeletons
Adults fly
ONLY crawlers transmit virus

Question 8

Difficult mealy bug control?

Answer 8

Waxy protective layer
Under barks and leaves
Weeds and other hosts
Limited chemistry- resistance

Question 9

Mealy bug dispersed

Answer 9

Own movement- crawl short distances
Wind
Birds/ants
Man- implements/agronomic activities

Question 10

Control of leafroll

Answer 10

Mealy bug: dormant spray(winter)- plant dormant- no predators/parasit
Corrective spray(summer): already see mealy bugs
Degree day model: mesly bugs not more 27- measure temp- hotter year- shorter life cycle

Pheromone traps: sticy paper- males trap

Biological control: cocktail ant win winter that feed on sap(honeydew)

Question 11

Virus elimination

Answer 11

Heat theraphy(meristem tip culture)
Somatic embryogenesis
Vector free tunnels- nucleur blocks

Question 12

Mass propagation

Answer 12

Nucleur block
Foundation block
Mother block
Nuseries

Question 13

Patterns

Answer 13

Random: seedling virus infection
Clumps: infection start 1 site- spread
Regularity: new block overlap other infection

Question 14

Runs

Answer 14

2-3 plants next to each other infected

Viruliferous mealy bugs

Question 15

Prim and sec infection

Answer 15

1-spread bring disease into block

2- spread within that block

Question 16

Modes if dispersion- different controls

Answer 16

Prevent spread from prev vineyard to given site
Prevent spread through infected planting material
Prevent secondary spread
Prevent spread from adjoining vineyards

Question 17

Fallow

Answer 17

Dont plant anything

Leave block

Question 18

Control phases

Answer 18

Phase 1- virgin soils- no vineyards ever- eliminate viruliferous- no volunteer

Phase2- ELISa in autumn- test pools.

LAMP- PCR replacement

Question 19

Holistic integrated control

Answer 19

Fallow
Adm infected blocks
Vector control
Prevent spread of adjoining blocks