Pests And Disease Flashcards
How can disease and pests affect yields
What are nematodes ?
They are microscopic worms that attack the roots of the vines interfering with water and nutrient intake
How can you deal with nematodes?
Prevention is better than cure
Sanitising the soil before replanting and using resistant rootstocks
How do birds and mammals affect yields?
They consume large volumes of grapes.
Half eaten or crushed grapes can promote fungal diseases
How can growers protect against birds and mammals?
Netting is the best option to prevent birds whereas protective fencing is needed to stop deer, wild boar or raccoons
Insects - what do insects feed on in the vineyard?
Both grapes and leaves
How can the grower treat the problem with insects?
Grower may choose to treat the problem with regular spraying of insecticides or more environmentally friendly techniques such as integrated pest management
What is Downey mildew and what conditions does it thrive in?
Downey mildew is a fungal disease which affects the green parts of the vine
What are the symptoms and side affects of Downey mildew?
Downey mildew appears as yellow dots on upper side of leaves and furry grey patches on underside of leaves.
It can cause leaves to drop prematurely as well as affecting inflorescences and young grapes reducing yields
What is powderey mildew and what conditions does it thrive in?
It’s a fungal disease which attacks the green part of the vine including leaves and the grapes
It thrives in warm shady humid conditions
What are the symptoms and side affects of powderey mildew?
It appears as a grey white powderey coating on green part of vine as well as leaves and grapes.
Grapes may shrivel, split and fail to ripen
Severe infections can cause leaves to dry up and fall off vine
What is Grey rot otherwise known as?
Botrytis cinerea
Where does grey rot thrive and what does it attack?
In damp conditions and it attacks the grapes
What are the side affects of grey rot?
It taints the flavours of the grapes and in black grapes leads to colour loss
How does grey rot turn to noble rot?
Noble rot is when white grapes in certain conditions are infected by botrytis and make sweet wines
How can you control fungal dieases?
By spraying fungicides
What fungicides do you spray to control powderey mildew?
Treated with sulphur based sprays
What fungicides do you spray to control Downey mildew?
Bordeaux mix a copper based spray
How is spraying using done?
By tractor
Which climate is spraying needed more and why?
Maritime climate due to high levels of rainfall in growing season
When and why should spraying stop?
Weeks before harvest to reduce harmful residues in the wine
How else can fungal infections be reduced?
Appropriate canopy management
An open canopy allows airflow and evaporation. This also reduces the need for expensive chemical sprays
What type of pruning can reduce the risk of fungal disease?
Trellised Vertical shoot positioning
What other diseases are present in the vineyard?
Viruses are common - most don’t kill the vine but limit its ability to function which can reduce yields and quality
How can growers treat viruses?
There are no cures or treatments and can only be eradicated by digging up the vine and sanitising the soil
How are bacterial diseases spread throughout the vineyard
By sharpshooters which are small insects
How can you treat bacterial diseases?
There are no cures or treatments. The only thing a grower can do is quarantine the vine and intercept the life of the sharpshooter which will prevent the spread. Once a vine is infected the only thing to do is dig up the vine and sanitise the soil
