Pest and Disease Management Flashcards
What can explain the level of damage of a disease in a vineyard?
quantity/quality of inoculum (example. quality of downy mildew dependent on winter weather conditions)
multiplication rate (dependent on weather conditions)
susceptibility of vine (phenology, cultivar)
cultural practices
What shape does fungal disease development take on a graph?
an S shape
How to manage fungal disease in a vineyard?
prophylaxis
chemical control
biological control
resistant varieties (4 available in France)
What prophylactic measures help manage fungal diseases?
Vigor control- shoot topping (except GM), leaf thinning, grass cover (only GM), fertilization management
Removal of unwanted shoots at the trunk of the base in spring (DM and BR)
Removal of primary inoculum (mummified berries, contaminated shoots) (BR)
Drainage (DM)
What is most effective in reducing grey mold?
Leaf thinning early in season (at fruit set)
Contact fungicides
No penetration of the product inside the plant
Leachable, will go away with rain
Newly formed organs are unprotected
Penetrating fungicides
distribution in all treated organs
not leachable
Newly formed organs are unprotected
Systemic fungicides
Distribution in all of plant by sap
not leachable
New formed organs are protected
When to spray?
When the crop is susceptible
when the pathogen is able to cause damages
when the previous spraying is no longer effective or washed out
How to combat fungicide resistance?
Alternate type of fungicide and don’t use the same mode of action two times in a row
Which element is active against downey mildew?
copper
Which element is active against powdery mildew?
sulfur
Why are there no specific sprayings for black rot?
If you combine downey/powdery mildew fungicides you will also treat BR if you choose properly.
All fungicides in organic viticulture are ________ fungicides.
contact
What is the copper restriction?
28 kg/ha for 7 years
Few fungicides have _____________ properties?
curative
Should spraying be based on curative positioning?
No, it should be preventative. There are few curative fungicides and they have an effect limited with time. (risk of resistance)
Antisporulant treatments
Destroy fruiting bodies of mycelium (but are not recommended)(risk of resistance); sweet orange oil
Preventative positioning
Spray before infection; all fungicides are effective
What form of sulfur is curative for powdery mildew?
powder
Why is grey mold difficult to manage?
no relation between latent botrytis and grey mold rate at harvest: strong relationship of post-veraison weather conditions; no risk forcasting model available
Grey mold favors:
grape berry moths
wounds
berry splitting
What is the most serious virus in viticulture?
Grapevine Fanleaf Virus
What transmits grapevine fanleaf virus?
nematodes