WSET DIPLOMA D1 HAZARD AND PESTS
How can winemakers deal with smoke taint? - answers :- analysis pre-harvest
- gentle handling of grapes
- low fermentation temp
- flash detente, reverse osmosis- blending with unaffected wines
What are the symptoms of phylloxera infestation? - answers :- vines die of drought in
patches that increase in size year by year
- vine roots are covered with the insects surrounded by yellow eggs
- swellings on older roots
- pale green leaf galls on the under-surface of the leaves
- slow, stunted shoot growth and leaf yellowing appears in around 3 years, the plant
dies after around 5 years
What determines the growth rate of powdery mildew? - answers :temperature, optimal
around 25c
What conditions are favorable to powdery mildew? - answers :- optimal temperature
(25c)
- shade
- can thrive in dry conditions
What causes downy mildew (peronospora)? - answers :a water mold that lives within
vine tissue, not on the surface
What is the main effect of downy mildew? - answers :attacks green parts of the vines,
defoliates
What conditions are optimal for downy mildew? What are its symptoms? - answers :-
rainfall- temperature = 20c
- yellow, circular 'oil spots' and then white, downy fungal growth on the underside of
leaves
How can powdery mildew be managed? - answers :- keeping an open canopy to reduce
shade and the density of leaves
- applications of sulfur
- systemic fungicides (can become resistant)
How can downy mildew be managed? - answers :- sprays made from copper salts
(bordeaux mixture) (protection from these copper sprays only lasts until 20 mm of rain
has fallen)
- other fungicides
- good drainage and an open canopy that dries quickly
How can winemakers deal with smoke taint? - answers :- analysis pre-harvest
- gentle handling of grapes
- low fermentation temp
- flash detente, reverse osmosis- blending with unaffected wines
What are the symptoms of phylloxera infestation? - answers :- vines die of drought in
patches that increase in size year by year
- vine roots are covered with the insects surrounded by yellow eggs
- swellings on older roots
- pale green leaf galls on the under-surface of the leaves
- slow, stunted shoot growth and leaf yellowing appears in around 3 years, the plant
dies after around 5 years
What determines the growth rate of powdery mildew? - answers :temperature, optimal
around 25c
What conditions are favorable to powdery mildew? - answers :- optimal temperature
(25c)
- shade
- can thrive in dry conditions
What causes downy mildew (peronospora)? - answers :a water mold that lives within
vine tissue, not on the surface
What is the main effect of downy mildew? - answers :attacks green parts of the vines,
defoliates
What conditions are optimal for downy mildew? What are its symptoms? - answers :-
rainfall- temperature = 20c
- yellow, circular 'oil spots' and then white, downy fungal growth on the underside of
leaves
How can powdery mildew be managed? - answers :- keeping an open canopy to reduce
shade and the density of leaves
- applications of sulfur
- systemic fungicides (can become resistant)
How can downy mildew be managed? - answers :- sprays made from copper salts
(bordeaux mixture) (protection from these copper sprays only lasts until 20 mm of rain
has fallen)
- other fungicides
- good drainage and an open canopy that dries quickly
