Chapter 8 - Part 2: Pests

Question 1

What is Phylloxera?

Answer 1

insect that feeds and lays eggs on roots. It damages the roots and reduces the uptake of nutrients and water. The damaged roots also become vulnerable to bacteria and fungi
Leads to death of the vine

Signs that a vineyard has an infestation:
vines die of drought in patches
vine roots are covered with the insects surrounded by yellow eggs
swellings on older roots
pale green leaf galls on the under-surface of leaves
slow, stunted growth, leaf yellowing in ~3yrs
plant dies in ~5yrs

mostly transported by humans - by equipment, water, dirt on shoes

Question 2

Phylloxera Management

Answer 2

1. grafting onto American rootstock - V. berlandieri, V. riparia, V. rupestris. They form hard, corky layers that surround the eggs, sealing the wounds and preventing invasion by bacteria or fungi
2. Single American varieties have little lime tolerance so rootstock hybrids between the various American species was created. Also done for other problems - nematodes, extreme soil pH, water stress, salinity, vigor

Question 3

What are nematodes?

Answer 3

microscopic worms that feed off vine roots
Reduces yield, vigor
transmits diseases (fanleaf virus is spread by dagger nematode)

Most common: root-knot nematode and dagger nematode

They are either already in the soil or spread by unclean nursery stock, irrigation water, or vehicles.

Once present can only be managed. not eliminated

Question 4

Nematode Management

Answer 4

1. fumigate soil but mostly banned now
2. plough in a cover crop of mustard plant that works as a biofumigant
3. use nematode-resistant rootstock ie Ramsey and Dog Ridge

Question 5

What are Grape Moths?

Answer 5

they feed on flowers and grapes
Many have several generations per season so attack from flowers in spring to grapes in fall
The wounds make them vulnerable to bacteria and fungi
causes significant crop loss

Question 6

Grape Moth Management

Answer 6

1. biological controls
   a. the bacterium Bacillus thuringiensis produces substances toxic to moths
   b. sexual confusion with pheromone capsules
   c. natural predators - wasps, spiders
2. insecticides

Question 7

What are spider mites

Answer 7

feed on the surface cells of leaves leading to discoloration, reduction in photosynthesis, delayed ripening, and reduction in yields

thrive in dusty conditions

most damaging to vines already water stressed

Question 8

Spider Mites Management

Answer 8

1. use water sprinklers, cover crops, or mulch to reduce dust
2. encourage predatory mites that feed on spider mites
3. pesticides

Question 9

Bird Management

Answer 9

1. netting
2. bird scarers or noises - must be rotated regularly
3. falcons

Question 10

Mammal management

They eat shoots, grapes, and leaves

Answer 10

Fencing