Hazards, Pests, Diseases

Question 1

Minimum amount of water needed a year for vine growth

Answer 1

500mm for cool climates, 750mm for warm climates

Question 2

Problem with drought

Answer 2

• close of stomach on leaves and reduces photosynthesis
• reduce grape size -> affect yield
• slow ripening -> unripe flavourful
• eventually vine may die

Question 3

Drought management option

Answer 3

• irrigation
• drought resistant rootstock (110R and 14R)
• drought tolerant variety (Garnacha)
• weed control (reduce competition)

Question 4

Problem with excess water

Answer 4

• too much vegetation -> competition
• high humidity -> fungal disease
• waterlogged of soil -> root damage
• compacted soil -> difficult to work with

Question 5

Management of excess water

Answer 5

• drainage system
• vineyard on slope
• vineyard on fre drained soil

Question 6

Problem with untimely rainfall

Answer 6

• pollination and fruit set -> millerandage and couture
• summer / veraison -> shoot growth slow ripening
• harvest
  –> swollen grapes, dilution of flavour
  –> grape splitting -> Grey rot
  –> difficult to use machine on wet soil

Question 7

Management option for untimely rainfall

Answer 7

• site management ( choice of soil, slope, drainage, cover plant)
• early harvest

Question 8

At what temperature would vine be seriously damaged

Answer 8

-20°C

Question 9

Management option for winter freeze

Answer 9

• site selection (altitude, near bodies of water, thick snow)
• grape varieties (Cab Franc, Riesling, hybrid with American or Mongolian parent (hardy -30°C)
• protecting vines (soil around vine graft, burying vines, pruned with several trunks)

Question 10

When does frosts occur

Answer 10

When cold air below 0°C collects at ground level, freezing water in the vines growing buds and shoots

Question 11

What is advective frost

Answer 11

Caused by large volumes of cold air moving in from very cold area

Question 12

What is radiative frost

Answer 12

• earth heated during the day, release heat at night
• on windless night, a layer of freezing cold air forms just above the surface of soil
• cold air denser than warm air, collect at valley bottom

Question 13

Management option for frost

Answer 13

• site selection -> avoid Frost pocket
• delay pruning to postpone budburst
• Grape varieties -> late budding (Riesling)
• vines trained high off ground
• soil (vs cover crop) absorbs more heat during the day
• water sprinklers (aspersion): release latent heat, for advective frosts
• wind machine: 4-7 m high, pull warmer air from above to down level; alternative: helicopter
• oil / propane gas burning heaters, wax candles (high cost of fuel and labour, low efficiency, pollution)

Question 14

What is hail

Answer 14

Pellets of frozen rain

Question 15

Management option for hail

Answer 15

• rockets fired to thunderclouds, seeding them with silver iodine to cause rainfall rather than hail
• netting (mendoza) (caution: shading)
• vine in plots in different area to diversify risk
• crop insurance