Treating Vines with Plant Extracts
A plant extract is a solution made from a plant. The goal is for the plant to release all the complex elements and molecules it contains into a solvent (water or alcohol).
It is important to differentiate macerations, decoctions, infusions, fermented extracts, essential oils, and plant juices. Each has a different preparation method and a different influence on the plant.
They can be used in a phytosanitary strategy (upstream and downstream) as well as growth stimulators for the plant (focus on photosynthesis) and the microbiological life of soils (focus on fermented extracts).
Plant extracts can be prepared on the farm.
Principle
Plant extracts have been used for millennia in agriculture. The development of biodynamic agriculture (technical itineraries focused on respect for life) and the search for alternatives to phytosanitary products mark a significant renewed interest in these products.
Plant extracts show three benefits in their use :
- Reduction of doses of copper and sulfur in the fight against downy mildew and powdery mildew
- Reduction of insecticides in the fight against pests
- Foliar Fertilization in the prevention of deficiencies
Modes of action
Plant extracts act on plants through various modes of action.
Plant extracts mainly act as plant defense stimulators but also have significant secondary effects on pathogens and pests : repulsion, competition, biocidal and fungicidal action.
Uses in viticulture
Plant extracts are used alone or added to the treatment mixture. In viticulture, plant-based products are infusions, decoctions, fermented extracts, essential oils, and plant juices.
These plant-based preparations can be valuable allies to maintain efficacy and satisfactory phytosanitary conditions while reducing doses of phytosanitary products. However, with current knowledge, their efficacy often remains partial and does not allow completely dispensing with copper and sulfur but aims at a dose reduction.
Other beneficial effects of applying plant preparations on the vine are to be noted. Some plants promote the development of the vine (growth, flowering, for example nettle) and others, its repair (healing, for example comfrey).
Which plants?
Species that may be of interest for vines are numerous and varied; they can be herbaceous or trees. The following paragraphs present 9 relatively common plants chosen for the benefits their extracts bring to the vineyard (vitalizing defenses, stimulating soil life, strengthening fungicidal preparations, frost prevention…), but many others exist (Wormwood, Peppermint, Rhubarb, Savory,...). It should be noted that the properties presented here are based on vineyard observations but not necessarily scientific studies.
Horsetail
Properties
- Strengthens the action of fungicides.
- Stimulates growth.
- Insect repellent.
Main constituents
- Silicic acid, alkaloids.
- Formic acid.
Uses
- Decoctions and herbal teas of stems.
Caution, horsetail plant extracts are drying and trigger an oxidative reaction in the plant, so they should be used in warm and humid weather.
Positioning
- At harvest.
- At storage.
- During plant protection.
Nettle
Properties
- Strengthens soil microbial flora.
- Stimulates natural plant defenses.
Main constituents
- Formic acid.
- Mineral elements.
Uses
- Infusions and fermentations of whole plants.
- Preparation of biodynamic compost no. 504.
Fermented extract can only be used on foliage in warm and dry weather; otherwise, it should be applied to the soil.
Positioning
- At storage.
- During photosynthesis.
Yarrow
Properties
- Strengthens the action of fungicides.
- Action against water stress.
Main constituents
- Isovaleric and salicylic acids.
- Flavonoids.
- Alkaloids.
Uses
- Infusions, decoctions or cold macerations of whole plants.
- Preparation of biodynamic compost no. 502.
Positioning
- Flowering.
- Veraison.
Buckthorn
Properties
- Strengthens the action of fungicides.
Main constituents
- Anthraquinones.
- Tannins.
Uses
- Decoctions and cold macerations of bark.
Positioning
- Plant defense.
Comfrey
Properties
- Strengthens soil microbial flora.
- Promotes cell multiplication (in case of hail or pruning wounds).
- Promotes flowering and fruit set.
Main constituents
- Allantoin.
- Boron.
Uses
- Fermentations (whole plant), infusions, concentrated juice.
Positioning
- At harvest.
- At storage.
- During leaf development.
German chamomile
Properties
- Promotes sugar formation in fruits.
- Regulates evaporation by stimulating the potassium cycle.
Main constituents
- Terpenoids.
- Flavonoids.
Uses
- Herbal teas of flowers.
- Biodynamic preparation no. 503.
Positioning
- At veraison.
Willow
Properties
- Strengthens the action of fungicides.
- Facilitates cuttings.
Main constituents
- Salicylic acid.
- Tannins.
- Flavonoids.
Uses
- Infusions of young wood bark.
Willow infusions should be used in warm and humid weather.
Positioning
- Plant defense (SDN).
Valerian
Properties
Main constituents
- Valeric acid.
Uses
- Infusions, juices and macerations of inflorescences.
- Preparation of biodynamic compost no. 507.
Positioning
- Against spring frost.
- At flowering.
Dandelion
Properties
- Promotes fruit ripening
- Stimulates natural plant defenses
Main constituents
- Salicylic acid
- Potassium
- Ethylene
Uses
- Herbal teas (from the beginning to the end of veraison) of whole plants or flowers
- Preparation of biodynamic compost no. 506
Positioning
- At harvest.
Available processes
Success conditions for a plant extract
- Favor rainwater
- pH of water between 6 and 6.5
- Prefer a stainless steel or copper cauldron and use a lid
- Control boiling
- Favor application of plant extracts in the morning
- Adapt extracts to your plots and the year's climate
- Beware of mixing plant extracts :
- Avoid mixing more than 2 plants at once
- Avoid mixing several decoctions, essential oils, and manures
- Alternate plants
Herbal teas and infusions, instructions
Once the plants of interest are chosen, the preparation steps for herbal teas and infusions are as follows :
- Cut plants into coarse fragments
- Immerse plant fragments in cold water
- Heat
- Turn off the heat when the water starts to simmer (from 80°C for willow and meadowsweet whose active principle, salicylic acid, is destroyed above this temperature)
- Cover and let infuse until cooled (infusion must last at least 20min)
- Dynamize or stir for 20min
- Filter
Once all these steps are completed, the herbal tea is ready for use.
Doses per hectare :
- 100 to 150 grams of dry plants in 5L of water / ha
or
- 800 to 1000g of fresh plants in 5L of water / ha
This preparation can be kept for a few days in the fridge or several months if bottled hot and stored cool and away from light.
Decoctions, instructions
Once the plants of interest are chosen, the preparation steps for decoctions are as follows :
- Cut plants into coarse fragments
- Let soak for 24h in water
- Heat and maintain boiling for 20 to 30min at a very low boil (90 to 100°C) and covered, to avoid losing vapors rich in essence
- Let cool without removing the lid
- Filter
- Dilute to 10% and spray
Once all these steps are completed, the decoction is ready for use.
Doses per hectare :
- 100 to 150 grams of dry plants in 5L of water / ha
or
- 800 to 1000g of fresh plants in 5L of water / ha
This preparation can be kept for a few days in the fridge or several months if bottled hot and stored cool and away from light.
Manures and fermented extracts, instructions
- Cut plants into fragments
- Immerse plant fragments in cold water
- Let ferment with a floating lid
- When there are no more fine bubbles rising due to fermentation, the extract is ready.
Fermentation lasts about 15 days at a temperature of 18 to 20°C.
- Filter carefully
- Dilute to 5-10% for foliar spraying and 20% for soil spraying.
Once all these steps are completed, the extract is ready for use.
Doses per hectare :
- 1.5kg of fresh plants macerated for 15 days in 10L of water
This preparation can be kept for several months in an airless container, cool and away from light.
Cold maceration, instructions
It is possible to perform a maceration cold, following these steps :
- Let finely cut plant fragments soak in water at room temperature for about 4h
- Filter
- Dilute to 5% for foliar spraying and 20% for soil spraying
Once all these steps are completed, the extract is ready for use.
Doses per hectare :
- 100g of dry plants in 5L of water
- Let macerate for 4h
Plant juices, instructions
Once the plants of interest are chosen, the preparation steps for plant juices are as follows :
- Coarsely cut the plant
- Let the plant ferment alone for 2 days
- Press the plant and collect the juice in a container
- Filter
- Dilute to 3-5% for foliar spraying and 10-20% for soil spraying
Once all these steps are completed, the plant juice is ready for use.
Doses per hectare :
- 1.5kg of fresh plants macerated
Advantages
- Natural products allowing significant biodegradability
- Many molecules present in plant extracts : multisite actions on bioagressors limiting resistance development
- Possibility of on-farm preparation
- Reappropriation of knowledge by the professional community
Disadvantages
- Low persistence of action : frequent treatment renewal
- Generally weaker action than synthetic products
- Time and variability of preparations
- Difficulty in sourcing "finished" extracts
- Inadequate and rather heavy regulatory frameworks
- Toxicity of "over" extracted products
Further reading
See the page Macérations, huiles essentielles et santé des cultures - Eric PETIOT.
Sources
- This page was created from PDF documents :
- "PLANT EXTRACTS TO CARE FOR VINES?", published by the Chamber of Agriculture of Var
- "The interest of plant extracts in organic viticulture and arboriculture", published by the CTIFL
- Vichard, J. (2021). Phytotherapy applied to vines explained by plants.
- Vichard, J. (2023). What is the role of nettle in the cycle of my vines? Le Pacte Végétal.
Appendices
Est complémentaire des leviers
S'applique aux cultures suivantes
Défavorise les bioagresseurs suivants
- ↑ Vichard, J. (2021). Phytotherapy applied to vines explained by plants.
