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
How long does grapevine fanleaf virus last?
a lifetime
What are the nepoviruses associated with grapevine fanleaf virus?
GFLV (grapevine fanleaf virus)
ArMV (Arabis Mosaic virus)
What makes controlling nematodes hard?
They have a long life span (can survive up to 7 years without food)
They have many host plants
They reproduce by parthenogenesis
How do you manage nematodes?
Devitalize and remove roots
Cultural practices (tillage, fallow period)
‘Suspressive plants’: oat, alfalfa, vetch
Resistant rootstock: Nemadex
What are the grapevine yellows?
a group of bacterial contaminations characterized by yellow and red leaves including flavescence doree and bois noir.
What spreads flavescence doree?
leaf hoppers
How many generations of the flavescence doree leaf hopper are there per year?
once with a long hatching period between the beginning of May to the end of June.
What spreads Pierce’s disease?
Sharpshooters, with varying lifecylces
What do the symptoms of Pierce’s disease mimic?
water stress
Will symptoms of trunk diseases appear every year?
No
What is the egg incubation time of grape berry moths?
5 to 15 days
Should spraying decisions be based off egg counting or larvae counting of grape berry moths?
larvae counting; eggs are hard to indentify
When will insect traps have bad efficiency?
during bad weather conditions; so have a net of traps with neighbors in the region
What is the purpose of egg counting?
For knowing when to position treatments
What is the purpose of trap monitoring?
For determining if counting should occur
What are the egg stages of grape berry moths?
Fresh egg (a few days old)
Yellow egg
Blackhead egg (just before hatching)
When you find the max trappings during a flight, how long should you wait to do larvae counting?
3-4 weeks
What is the grape berry moth threshhold?
5 glomerulus/100 bunches
Are insecticides more effective on young larvae or old larvae?
young larvae
How much is mating disruption?
200-250 euros/ha
What are the kinds of chemical insecticides?
insect growth regulators/inhibitors
neurotoxins
When spraying insecticides should you spray on the whole canopy?
No;
also don’t mix fungicide treatments because you are not spraying the whole area
“choc”, action
duration of efficiency of insecticide; range of time you can spray insecticide; maximum of age affected by insecticide.
Ex. if you have ‘choc’ of 1 day, you have to position it precisely at the stage for good efficiency
What is the glomerulus?
When several flowers are kept together due to silk nest of grape berry moths.
Why are parasites still inoperative at this time?
They are still not well understood in how to introduce them (nests?). Plus you must introduce a lot to be infected.
What are the generalist beneficial insects?
ladybugs, mites, harvestmen, lacewings, heteroptera, spiders
What should you not use to preserve beneficial insects?
neurotoxins
How often should you renew organic pesticides?
every 20 mm of rain
What is the pesticide approval process in Europe?
- European approval for active substance
- National approval for formulated product
What is included in the approval process?
classification for toxicological, ecotoxicological, and environmental hazards
hazard and precautionary statements
preharvest interval
interval between applications
distance to water zones (nontreated areas)
What is a formulated product?
1 or several active substances with coformulants
What is included in the registration?
1 dose for 1 target on 1 crop, under specific proper conditions
What is the restricted entry interval?
the duration in which you can not go into the vineyard after spraying; depends on hazard statement
minimum is 6 hours (12 hours in Bordeaux)
closed environment (8 hours)
irritant products for skin and eyes (24 hours)
sensitizing products (48 hours)
What is the bee hazard mention?
you can spray during flowering during times when bees aren’t there
normally you can’t use insecticides during flowering so you don’t arm pollinators (for crop or if you have flowering grass cover; must destroy flowers first)
Can you mix any products?
No; you must check first
What regulations are in force with spraying?
wind speed <20 km/hr; cannot spray
max copper 28 kg/ha for 7 years
no noise pollution from 22:00 to 6:00
prefectural orders to preserve places hosting vulnerable people
What are good conditions for the use of pesticides?
do not spray in high wind, high heat, or under wind
spray before the rain
respect the renewal rates of the products
shoot or leaf top before spraying
respect dying and penetration time (between 1 to 4 hours)
adjust volume of mixture to vegetation surface
if possible use recovery panels for early treatments
control sprayer and spray quality (avoid wasting product/check nozzles)
Why should you not spray for grape berry moths and grey mold at the same time as other treatments?
Because you are only spraying the bunches and not the canopy
