Vine Diseases and Insect Threats

Question 1

Diseases that affect the vine

4 main groups

Answer 1

• Fungal
• Viral
• Bacterial
• Phytoplasma

Question 2

How fungal diseases manifest

Answer 2

Fungal diseases manifest as mildew or mold and are typically associated with warm and damp climates, attacking either the root system or the canopy of the grapevine

• img. Downy Mildew

Question 3

How fungal spores spread

Answer 3

Fungal spores are spread by wind and rain and a disease, once entrenched in a vine, may infect an entire vineyard

Question 4

Most worrisome fungal diseases

Answer 4

downy mildew, powdery mildew

• Originated in America, arriving in Europe on cuttings in the 19th century

Question 5

Phytoplasma diseases

aka

Answer 5

grapevine yellows

Question 7

Cause of phytoplasma diseases

Answer 7

phytoplasmas

• Pathogens similar to bacteria, yet they are symptomatically similar to viral diseases and, like viruses, must be spread through an insect vector or rootstock grafting

Question 8

Fungal disease

Powdery Mildew

aka

Answer 8

Odium

Question 9

Fungal disease

Downy Mildew

aka

Answer 9

Peronospora

Question 10

Fungal disease also called dead arm

Answer 10

Eutypa Dieback

Question 11

Fungal disease

Esca

aka

Answer 11

Black Measles

• Esca (Black Measles) is one of the earliest known fungal grapevine diseases

Question 15

Where and when phytoplasma diseases were first recorded

Answer 15

Europe, mid-1990s

• May cause widespread difficulties in the 21st century

Question 16

Fungal Diseases

6 examples

Answer 16

Fungal Disease

• Powdery Mildew (Oidium)
• Downy Mildew (Peronospora)
• Eutypa Dieback: aka dead arm
• Esca (Black Measles)
• Black Rot
• Bunch Rot

Question 17

Bacterial Diseases

3 examples

Answer 17

Bacterial Diseases

• Pierce’s Disease
• Crown Gall (Black Knot)
• Bacterial Blight

Question 18

Viral Diseases

2 examples

Answer 18

Viral Diseases

• Leafroll Virus
• Fanleaf Degeneration

Question 19

Phytoplasma Disease

1 example

Answer 19

Phytoplasma Diseases

• Flavescence Dorée:
  
  • Form of grapevine yellows
  • 1st appeared in Armagnac in 1949
  • Spread by Leafhopper insects and propagation of infected vines
  • Initial delayed budbreak and slow shoot growth, eventually causes bunches to fall off the vine and berries to shrivel
  • Discolors leaves, causes pustules and cracks to form, and may kill young vines
  • No cure exists, although insecticides may be used to control leafhopper insect populations and retard its spread