Using Phosphonates in the Fight Against Downy Mildew
The use of phosphonates in biocontrol (potassium phosphonate, disodium phosphonate) is an interesting alternative to copper given their effectiveness[1].
Phosphonates are salts of acid phosphorous acid, derived from phosphate rocks[2]. Phosphonates have fungicidal properties. Numerous trials in different countries have shown the effectiveness of phosphonates against many diseases caused by fungi: Grapevine downy mildew, Phytophthora of trees fruit trees, Pythium,...
How does it work?
Biocontrol phosphonates have a dual activity: fungicidal and plant defense stimulator. They act directly on the pathogen (main fungicidal effect) but also indirectly by stimulating plant defenses, notably activating phytoalexins.
Biocontrol phosphonates are used preventively.
Their use counts in the biocontrol IFT but not in the general IFT.
In case of low pressure, using phosphonates alone is possible but it is recommended to combine them with a partner contact fungicide at a reduced dose, to complement leaf efficacy and ensure optimal plant protection. Managing intervals between applications is as important as with any other fungicide, especially in case of heavy rainfall.
Benefits
- Using phosphonates allows to save on average 20 to 25% of the dose of conventional fungicides, i.e. a reduction of about 1.5 IFT per year on a standard protection schedule.
- In exceptional situations of high disease pressure, phosphonates provide essential additional protection to fungicide use without adjusting their dose and thus without reducing the IFT.
- Phosphonate is biodegradable in soil.
- Low risk of resistance.
- It does not affect beneficial insects and mites.
- Aquatic organisms are much less affected by phosphonate than by copper.
- Using phosphonates does not generate additional cost compared to conventional references, with similar efficacy.
Limits
- Phosphonate sprays systematically lead to residues of phosphorous acid in wines. These residues are below MRLs and safe for consumers.
- Prohibited in Organic farming.
Cost
40 to 55 euros per ha for downy mildew protection (compared to 40 to 60 euros per ha for conventional protection).
Commercial solutions
Phosphonates are available on the market under the commercial names: Results on the Ephy website
Sources
- ↑ Contrat de Solutions, Fighting downy mildew on grapevine using biocontrol phosphonates
- ↑ Agriclean, Phosphites
Appendices
Est complémentaire des leviers
- Practicing biocontrol using natural substances
- Practicing biocontrol
- Practicing biocontrol in viticulture
S'applique aux cultures suivantes
