Diseases

Question 1

What is oidium also known as?

Answer 1

Powdery Mildew

Question 2

Where is generally the only fungus found?

Answer 2

California

Question 3

What type of weather does oidium like for germination?

Answer 3

Cooler weather

Question 4

What temperature is ideal for rapid development of oidium?

Answer 4

70-90F

Question 5

What does oidium attack?

Answer 5

Leaves and fruit

Question 6

What prevents oidium?

Answer 6

sulfur dust

Question 7

What vinifera grapes are most susceptible to powdery mildew?

Answer 7

Carignane, Muscat of Alexandria, Sylvaner

Question 8

How does downy mildew germinate?

Answer 8

In a film of water on the vines

Question 9

What does down mildew affect earlier in the year?

Answer 9

Leaves, tendrils, berry clusters, petioles, shoots.

Question 10

Which vinifera are most susceptible to downy mildew?

Answer 10

Chardonnay, Riesling

Question 11

What is the most effective treatment for downy mildew?

Answer 11

Bordeaux mixture

Question 12

What are the ingredients of Bordeaux mixture?

Answer 12

Copper sulfate
Slaked lime
Table salt
Water

Question 13

Where is Black Rot most dangerous in the US?

Answer 13

East

Question 14

In what kind of weather does black rot germinate?

Answer 14

Warm, humid weather

Question 15

What does Black Rot attack?

Answer 15

leaves

Question 16

What is an effective combatant to Black Rot?

Answer 16

Bordeaux mixture

Question 17

How does Black Rot initially look on a vine?

Answer 17

As black spots on the vines shoots, leaves and berries.

Question 18

What causes Black Rot?

Answer 18

The Guignardia bidwelli fungus

Question 19

How did black rot spread to Europe?

Answer 19

With the importation of phylloxera-resistant rootstocks in the late 1800s.

Question 20

Where is Black Rot native to?

Answer 20

North America

Question 21

When does Noble Rot develop?

Answer 21

Later in the season

Question 22

What is noble rot known as in Germany? In Italy?

Answer 22

Edelfaule, Muffa

Question 23

Why is later day dry weather vital to good wine, with regards to noble rot?

Answer 23

If there is unrelenting heat and dryness, then the fungus will not actually develop, and grapes will accumulate sugar, rather than undergoing the chemical transformations associated with noble rot. But the medium of warm, sunny, dry days after the moisture will create the idea growing conditions.

Question 24

What is the color transformation of grapes infected with the noble rot?

Answer 24

Golden -> pink or purple -> brown

Question 25

How does botrytis affect these 3 factors of a grape?... Sugar Tartaric Acid Malic Acid

Answer 25

Sugar - Decrease by 1/3 Tartaric Acid - Decrease by 5/6 Malic Acid - Decrease by 1/3

Question 26

What does botrytis form in a grape?

Answer 26

Glycerol, acetic acid, gluconic acid, laccase, pectinase, other enzymes, botyticine (a yeast-inhibiting glycoprotein).

Question 27

What is glycerol?

Answer 27

A polyol and minor product of fermentation, usually present from 5-12 grams/liter, but in botrytized wines up to 25 g/l.

Question 28

At what temperature does Noble Rot grow best?

Answer 28

65-75 (18-24)

Question 29

What do vines infected with Eutypa Dieback experience?

Answer 29

Stunted shoot growth, as the fungus releases toxins, and potentially causes the death of a cane.

Question 30

What does Eutypa Dieback primarily affect?

Answer 30

yield

Question 31

How does Eutypa Dieback enter the vine?

Answer 31

carried by rain, entering the vine through pruning wounds.

Question 32

What causes Eutypa Dieback?

Answer 32

The Eutypa lata fungus

Question 33

What is Eutypa Dieback also known as?

Answer 33

Dead Arm

Question 34

Esca-infected vines rarely live past what?

Answer 34

30 years of agents

Question 35

What can Esca do to older vines?

Answer 35

It affects the wood, causing the interior of the trunk and arms to soften and rot from the inside.

Question 36

What does Esca do to young vines?

Answer 36

Weaken growth, affect berry development and discolor leaves. Death may occur in hot weather.

Question 37

Where does Esca thrive?

Answer 37

warmer climates

Question 38

What is Esca also known as? What kind of disease is it?

Answer 38

Black measles Fungal

Question 39

What does downy mildew cause?

Answer 39

Dropping of vine leaves, which limits the vine's ability to photosynthesize.

Question 40

What is the agent of downy mildew?

Answer 40

Plasmopara viticola

Question 41

What can mealy bugs of the genera Planococcus and Pseudococcus spread?

Answer 41

Leafroll virus

Question 42

What are some indirect effects of mealybug's sap sucking?

Answer 42

They produce a lot of "honeydew" which collects over the bunches and foliage, and on which fungus grows, often giving it a sooty appearance.

Question 43

When and where was the first vine mealy bug indentified?

Answer 43

California's Coachella Valley in the early 1990s

Question 44

Mealy bugs prefer a _____ environment.

Answer 44

humid

Question 45

When do mealy bugs become mature and reproduce?

Answer 45

early summer

Question 46

Which mealy bug can feed on roots?

Answer 46

Planococcus ficus

Question 47

What are mealy bugs and what do they do?

Answer 47

Small white insects of the family Cicadellidae which suck vine sap, infect new growth in the spring, typically at the undersurface of the leaves.

Question 48

What are phytoplasmas?

Answer 48

Pathogens similar to bacteria, yet symptomatically similar to viral diseases.

Question 49

How are viral diseases spread in the vineyard.

Answer 49

Through grafting or from transmission from insects.

Question 50

What climates are fungal diseases typically associated with?

Answer 50

warm and damp climates

Question 51

How do fungal diseases manifest?

Answer 51

As mildew or mold

Question 52

What is powdery mildew?

Answer 52

aka oidium A fungal disease native to North America, spread to France & noticed in 1847. Green parts of the vine are attacked, and a cobweb like growth spreads. Ash-like spores soon show up on short, upright stalks.

Question 53

What are examples of agrochemicals?

Answer 53

fungicides, insecticides, herbicides, bird repellents, plant growth regulators, rodenticides, soil fumigants

Question 54

A common feature of vineyards with a reputation for producing high-quality wines is that they are of _____ vigor, and that the canopy microclimate is characterized by _____ and _____ shade.

Answer 54

- moderate to low - good exposure of leaves and fruit to the sun - little

Question 55

What is the full two names for phylloxera?

Answer 55

Phylloxera Vastatrix | Phylloxera the destroyer

Question 56

What does phylloxera attack? What does this cause?

Answer 56

The vines...it lowers the sap pressure level.

Question 57

How are those affected vines vulnerable?

Answer 57

New pathogens can attack the vine

Question 58

What is Millerandage?

Answer 58

It affects big variation in grape size

Question 59

What grapes are affected by millerandage?

Answer 59

Gewurztraminer, Chardonnay 1a & Mendoza clones

Question 60

What is couloure?

Answer 60

Failure of grapes to develop after flowering

Question 61

When does couloure usually happen?

Answer 61

Spring

Question 62

Why does couloure happen?

Answer 62

The vine is trying to conserve resources

Question 63

What grapes are prone to couloure?

Answer 63

Grenache, malbec, merlot, muscat ottonel

Question 64

What is Crown Gall also known as?

Answer 64

Agrobacterium Tumefaciens

Question 65

Where and when does crown gall happen?

Answer 65

On vines injured by winter freeze

Question 66

What transmits the bacteria that causes Pierce's Disease?

Answer 66

Glassy winged sharpshooter

Question 67

What is the bacteria that causes Pierce's Disease?

Answer 67

Xylella Fastidiosa