Destroying Weeds and Regrowth Potentially Hosting Bioaggressors
1. Presentation
Characterization of the technique
Description of the technique:
Hoe for organic aromatic plants
| Julien Halska | INRA | julien.halska(at)grignon.inra.fr | Dijon (21) |
Destroy (preferably mechanically) the weeds and regrowth likely to host bioagressors of crops. This involves 1) properly managing weed control in the fields 2) monitoring the weeds in borders, wheel tracks and grass strips (mowing before flowering, weeding hotspots) and 3) controlling regrowth of certain crops. This may require additional operations or modifying the schedule of planned operations (destruction of rapeseed regrowth before emergence of rapeseed in neighboring fields).
Example of implementation: Generally, hoeing is very effective for eliminating sunflower regrowth in spring, in all fields where regrowth is likely to develop. In cereals, if the cover is not suitable for hoeing or if equipment is not available, a post-emergence herbicide can be applied.
Implementation period On established crop
In the case of managing bioagressor hosts confined to the field, this technique has a preventive effect in the rotation.
Spatial scale of implementation Field
Farm
Territory
Depending on the interannual dispersal distance of the bioagressor to be controlled, as hosted bioagressors can be maintained on the same field, or spread to neighboring fields, or even further away.
Application of the technique to...
All crops: Sometimes difficult to generalize
Some regrowth should be monitored more closely (potato, grasses, sunflower).
Potato: managing potato regrowth in subsequent crops is essential for controlling late blight (removal of as many tubers as possible at harvest, no ploughing after harvest to expose to frost, chemical or mechanical interventions in following crops).
Durum wheat, Winter wheat, Spring wheat, Spelt, Einkorn (Small Spelt): destroy cereal regrowth against brown and yellow rusts (at territorial level), against powdery mildew, against bunt (before heading, in contaminated fields). Manage regrowth of cereals and sensitive grasses in rotation against take-all.
Grassland: destroy regrowth before planting behind cereals or in nearby fields. Remove mowed vegetation quickly.
Winter oat, Spring oat: against oat helminthosporiosis: control wild oat which is host of the disease. Destroy cereal regrowth against crown rust (at territorial level), against powdery mildew.
Winter barley: manage regrowth of cereals and sensitive grasses in rotation against take-all. Destroy cereal regrowth against powdery mildew.
Winter rye: manage regrowth of cereals and sensitive grasses in rotation against take-all. Destroy regrowth (at territorial level) against stripe rust.
Winter triticale: manage regrowth of cereals and sensitive grasses in rotation against take-all. Destroy regrowth (at territorial level) against brown and yellow rusts.
Spring triticale: destroy wheat and triticale regrowth (at territorial level). Destroy cereal regrowth against powdery mildew.
Winter rapeseed, Spring rapeseed: destroy secondary host weeds of broomrape. However, encourage regrowth for one month (to germinate broomrape seeds and then destroy the plants). Destroy rapeseed regrowth in neighboring fields before sowing.
Sunflower: destroy regrowth after sunflower, but also in neighboring fields and fallows. Control secondary host weeds (ragweed, bidens, centaureas, cocklebur, etc.).
All soil types: Easily generalizable
All climatic contexts: Easily generalizable
Regulation
2. Services provided by the technique
3. Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality: Variable
phytosanitary emissions: DECREASE
GHG emissions: VARIABLE
Effect on water quality: Increasing
pesticides: DECREASE
Effect on fossil resource consumption: Variable
fossil energy consumption: VARIABLE
Other: No effect (neutral)
Pollutant transfer to water (N, P, phytosanitary ...): Decrease
In cases where the technique reduces the use of products likely to pollute water resources.
Pollutant transfer to air (N, P, phytosanitary ...): Decrease
In cases where the technique reduces the use of products likely to diffuse into the air.
Fossil energy consumption: variable
Possible increase if destruction requires specific interventions.
GHG emissions: variable
Possible increase in CO2 emissions if destruction requires specific interventions.
"Agronomic" criteria
Productivity: No effect (neutral)
Soil fertility: No effect (neutral)
Water stress: Variable
Their destruction prevents regrowth and weeds from consuming water. This effect is proportional to the amount of plants destroyed. In the case of shallow tillage, drying of the upper soil layer may occur, however breaking capillaries also limits evaporation.
Functional Biodiversity: No effect (neutral)
Negative effect on soil macrofauna in case of shallow tillage?
"Economic" criteria
Operational costs: Variable
Decrease if treatment savings are made, or if crop losses are avoided.
Mechanization costs: Variable
Increase in case of additional interventions. No effect if shifting planned intervention anyway.
Margin: Variable
Effect on margins depends on the balance between possible additional costs, treatment savings and losses avoided.
"Social" criteria
Working time: Variable
Increase in case of additional interventions. No effect if shifting planned intervention anyway.
Observation time: Increasing
It is necessary to closely monitor weed flora, including in borders and grass strips.
4. Organisms favored or disadvantaged
Favored bioagressors
| Organism | Impact of the technique | Type | Details |
|---|
Disadvantaged bioagressors
| Organism | Impact of the technique | Type | Details |
|---|---|---|---|
| common bunt of wheat | LOW | pathogen (bioagressor) | |
| oat helminthosporiosis | pathogen (bioagressor) | ||
| potato late blight | MEDIUM | pathogen (bioagressor) | Very important preventive measure. |
| sunflower downy mildew | MEDIUM | pathogen (bioagressor) | Destroy regrowth and control secondary host weeds (ragweed, bidens, centaureas, cocklebur, etc.). |
| branched broomrape | MEDIUM | weeds | Destruction of secondary host weeds is essential to limit its spread. However, encouraging regrowth for one month allows broomrape seeds to germinate and then destroy the plants. |
| powdery mildew of cereals | pathogen (bioagressor) | Powdery mildew can survive during summer on regrowth. | |
| phoma of crucifers | MEDIUM | pathogen (bioagressor) | Destroy rapeseed regrowth in neighboring fields before sowing. |
| take-all | pathogen (bioagressor) | ||
| brown rust | pathogen (bioagressor) | Destroy wheat and triticale regrowth (at territorial level). | |
| crown rust | pathogen (bioagressor) | Destroy oat regrowth (at territorial level). | |
| stripe rust | pathogen (bioagressor) | Destroy rye regrowth (at territorial level). | |
| yellow rust | pathogen (bioagressor) | Destroy wheat and triticale regrowth (at territorial level). | |
| pea thrips | pest, predator or parasite | For lentil, volunteer soybean shoots have been reported as sources of thrips infestation. | |
| zabrus | pest, predator or parasite | Destroy cereal regrowth in the field where a grassland will be sown or in nearby fields. Remove mowed vegetation quickly. |
Favored Auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Disadvantaged auxiliaries
| Organism | Impact of the technique | Type | Details |
|---|
Favored climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
Disadvantaged climatic and physiological accidents
| Organism | Impact of the technique | Details |
|---|
5. For further information
- Cahier technique. Common bunt of wheat
- -Fontaine L. and Hédont M. (ITAB); Caron D., Bernicot M.H., Robin N. (Arvalis); Fougereux J.A., Collin F. (FNAMS); Maurice R. (Regional Chamber of Agriculture of Pays de la Loire); Mercier F. (RSP)
ITAB, Technical brochure, 2007
- Rapeseed - Branched broomrape
Terres Inovia, Website, 2017
- Potato late blight. The method to protect against it
Perspectives Agricoles n°343, March 2008, pp 56-58, Press article, 2008
- Technical assistance memo for implementing good practices in plant health
- -Délos M. et al. (DRAAF- SRAl)
DRAAF-SRAl, Book, 2011
Source of data on beet, potato and flax. Document not published.
- Sunflower - Late blight: control methods
- -Terres Inovia
Terres Inovia, Website, 2017
6. Keywords
Bioagressor control method: Cultural control
Mode of action: Action on initial stock
Type of strategy regarding pesticide use: Redesign
Annexes
S'applique aux cultures suivantes
