PEST & DISEASE MANAGEMENT Flashcards
Name the four most important fungal diseases
Downy mildew
Powdery mildew
Black rot
Grey mould (botrytis)
Name the two most important vine virusses
Fanleaf virus
(Leafroll virus)
Name the two most important vine bacterial diseases
Grapevine yellow (Bois Noir & Flavescence)
Pierce’s disease
What is typical for downy mildew? (5)
Multiple cycles
Weather dependant
Risk as long as the stomata work
10-15 days incubation times
‘Oil’ spots on leaves and grey/brown rot on clusters
What do the oospores of downy mildew need in order to germinate?
Min 11C in spring and rain. ‘Splash’ effect
What is causing powdery mildew?
Erysiphe Necator, originally from north America
What is typical for powdery mildew? (6)
Risky earlier in the season (with UV)
Multiple cycles
Attacts young leaves
Flag symptoms + grey/white powder on two sides of the leave
Need humidity (not especially rain)
No new infections after bunch closure
What his causing black rot?
Guignardia Biwellii, originally from north America
What is typical for black rot (4)
No new infection after stop growth
Maximum damage at fruitset
Mummification of berries + necrosis shoots
Multiple cycles –> needs rain
What is typical for black rot (5)
No new infection after stop growth
Maximum damage at fruitset
Mummification of berries + necrosis shoots
Multiple cycles –> needs rain
10 Days incubation (=longer) so less cycles
What is typical for grey mould? (4)
Causes problems for all kinds of crops
Latent phase between flowering and veraison (lazy mould goes for the juice!)
Needs rain
Infection at flowering, damage shown at veraison
What can influence the level of damages? (5)
Weather
Timing of infection + multiplication rate
Viticultural practises (pruning/canopy etc)
Susceptibility of the variety
Quantity and quality of the inocuum
Name 4 ways to manage diseases in the vineyard
Prophylaxis
Chemical control
Biological control
Resistant varieties
What is the difference between contacts-/penetrating-/systemic fungicides?
Contact: no penetration / leachable
Penetrating: penetrating / leachable
Systemic: penetrating / not leachable / also for new organs
When do you spray for downy mildew?
Between flowering and fruitset
At veraison
When do you spray for powdery mildew?
Between flowering and bunch closure
Or when flag symptoms appear
When do you spray the clusters for grey mould?
Flowering
Bunch closure
Veraison
Not recommended: 2-3 wk before harvest
What is the vector of Fanleaf virus?
Infected nematodes in the soil
Xiphinema Index - can survive for 7 years
Many host plants
Why is it so difficult to get rid of Fanleaf virus?
Because the vector can survive for 7 years in the soil also when the vineyard is uprooted.
What is the vector for Flavescence Doree?
Infected leafhopper
Scaphoideus Titanus
Phytoplasma: Candidatus Phytoplasma Vitis (infected for life)
How many generations does a leafhopper have per season?
Just one. So one spraying per year is enough.
Why is it so difficult to treat against FD?
Minimum 1 year between inoculation and symptoms. When you realise it, it is too late. You can only treat the vector, not the disease
What is the vector for Pierce’s disease?
Leafhopper & Xylella Fastidiosa
Blue-green sharpshooter
Green sharpshooter
Red-headed sharpshooter
Glassy-winged sharpshooter
Why are the sharpshooters difficult to treat?
Because they don’t spend their whole lifecycle in the vineyard
Name 3 closely related trunk diseases
Esca
BDA (black dead arm)
Apoplexy
Can you cure trunk diseases?
No. They are infected for life. The necrosis wil spread over the years and eventually the vine will die. Till then you can still harvest grapes from this vines
What causes eutypa dieback?
A fungus. Eutypa lata
Why is eutypa dieback hard to treat?
Fungus is being spread by wind and rain
Vine is getting infected via pruning wounds
Fungus can survive on dead arm for 5 years
4-8 years of incubation time
How do you see the difference between eutypa dieback and esca?
When you cut the trunk:
Esca: necrosis in the middle of the trunk
Eutypa: sectorial necrosis
What is the vector of leaf roll virus?
Grape berry moths (3 generations)
Multiple generations
They host in grapes, piercing the skin and inducing grey mould
What are the most important practical things to think of when spraying? (4)
Don’t spray with high wind (<20km/h)
Spray before the rain
Respect the renewal rates of the product
Control spray quality
Which 4 treatments are mostly combined?
Downy mildew
Powdery mildew
Black rot
Insecticides for leaf hoppers
!! Only if allowed to mix
What is the ‘bee label’?
Label at insecticides that are no harm for bees. Otherwise not allowed to spray during flowering (also not during flowering of the cover crop)
What are ‘parasitoids’?
Insects that lay their eggs/larvae in the body of the pest species. It will not kill the host immediately, but it will make them less effective.
What is a downside of pesticide use?
It will kill all insects, also the beneficial ones.
What do we mean by ‘connectivity’?
The ability for insects/animals to move from one habitat to another.
Via trees/hedges for example.
