Monitoring and Control

Nutsedge in leeks

Yellow nutsedge is no ordinary weed for a number of reasons:

• It belongs to the sedge family, which is why graminicides (=grass-weed herbicides) are not effective against it.
• There are no effective herbicides for many crops.
• Basically, it propagates vegetatively (via tubers).
• The tubers are dispersed everywhere via machinery, vehicles, footwear, etc.
• The number of tubers in the soil of an infested field increases rapidly.

Preventive Measures

Nutsedge can be defeated if identified sufficiently early. Regular monitoring of the plots is the only way to achieve this early identification. Prophylactic measures aim to prevent the formation of new tubers and their propagation in non-infested plots. Said measures are applied in all affected geographic areas.

• Mark the contaminated areas and cultivate them separately.
• Notify owners of farm machinery to enable them to plan their farming operations.
• As far as possible, machinery and equipment used in infested fields should not be used in non-infested fields.
• Remove all visible soil from the machinery in situ and after each use.
• The earth resulting from the washing of the machinery and root crops must be returned to an already-contaminated field. Particular attention must be paid to inputs of soil from outside sources as well as to the movement of soil.
• Clean soiled tracks and roads.
• Use uncontaminated plants, soil and compost only.
• Do not plant root crops in contaminated fields (because of the high risk of contagion).

Indirect Measures

The spread of the tubers is a key factor in field infestation, and the involvement of all stakeholders is necessary to reduce this spread. Farmers need to report their outbreaks to allow contractors to optimise the use of machinery (e.g. a machine for exclusive use in infested fields).

Making the reporting of outbreaks and the control of nutsedge obligatory would be an effective way of slowing the infestation of new fields. This obligation must form part of a comprehensive national strategy.  Producers and contractors must not feel as if they are being punished.

Direct Measures

In addition to preventive and indirect measures, an individual control strategy must be developed in cooperation with the cantonal authorities whenever a contamination is ascertained. Direct measures will then be implemented depending on the specifics of each situation.

Initial Contamination

These measures are used when an early discovery is made. They must be implemented before new tubers are formed, i.e. in early summer.

• Grub up plants individually with their rhizomes and tubers.
• Infected soil must be disposed of in general waste or in landfill, but not in compost.
• Prevent propagation by seed by not allowing the plants to flower.

Minor Outbreaks

• Mark the affected areas to ensure monitoring over the following years.
• Halt tillage and harvest work in order to reduce the risk of propagation both within and outside of the plot.
• Establish an individual control strategy in cooperation with the cantonal authorities.

Said control strategy may include:

• Plant-by-plant application of an effective herbicide
• Hoeing the earth where the outbreak occurs according to the contaminated depth.
• Soil disinfection or sterilisation.

Contaminated Land

These measures do not permit total eradication of the tubers, and require time and persistence to achieve remediation. An integrated approach must be favoured. Mechanical and chemical measures must be combined with a reorganisation of crop rotations to allow the stages of the crops and the dates of farming operations in these crops to be adjusted to the life cycle of nutsedge.  A custom-tailored control strategy implemented in cooperation with the cantonal authorities might include:

• Application of an effective herbicide on the young plants
• Hoeing the soil where the outbreak occurs according to the contaminated depth
• Soil disinfection or sterilisation
• Adjustment of the crop rotation
• Non-cultivation during a remediation period.

 

In presenza di un’infestazione di zigolo dolce, la prevenzione e le misure di contenimento indirette vanno affiancate, d’intesa con l’autorità cantonale, da una strategia di lotta specifica, che prevede l’applicazione di misure dirette, in funzione delle diverse situazioni.

La scheda tecnica sullo zigolo dolce fornisce molte informazioni sulle misure di lotta diretta che è possibile applicare a seconda del livello d’infestazione riscontrato.