Application of Pythium oligandrum against wheat fusarium

Pythium Oligandrum is a mycoparasitic oomycete. It parasitizes a large number of phytopathogenic fungi such as Fusarium graminearum and Sclerotinia sclerotiorum.

Pythium oligandrum can be found in commercial solutions listed here.

How does it work?

Pythium Oligandrum grows towards pathogenic fungi, enters into competition with them and parasitizes them. Then it degrades the cell wall of the target fungi by enzymatic action to colonize them, thus causing the death of the host. While mycoparasitism is the main mode of action of Pythium oligandrum, it also acts as a plant defense stimulator (PDS) by inducing the synthesis of specific proteins. It accelerates root growth by stimulating the production of growth phytohormones. The absorption of phosphorus and trace elements by the plant is thus favored.

Trials on rapeseed

In the Terres Inovia trials of 2016, POLYVERSUM used alone showed an efficacy of about 30% on stem with 11% of plants having attacked stems. However, persistence was not sufficient to protect secondary branches, unlike references based on boscalid or prothioconazole. Although close to the references, the efficacy of the pack combining POLYVERSUM with metconazole or tebuconazole at half dose remains behind compared to Propulse or Pictor Pro at full or half dose.

Trials on wheat

Arvalis has tested Polyversum since 2016 in combination with metconazole and also with prothioconazole and tebuconazole. In these trials, the contribution of Polyversum was judged low and variable, whether used alone or in mixture. Trials set up by the Chamber of Agriculture of Nord Pas de Calais go in the same direction. The addition of Polyversum at T3 on the Fructidor variety did not provide a yield gain.

Benefits

No known environmental impact
Reduction of the IFT in combination with a fungicide
Positioning identical to fungicides
Prevention of the risk of resistance development

Limitations

Living organisms with variable efficacies
Cost compared to a conventional fungicide at full dose
Use not recommended in low volume due to clogging issues with some filters
Cannot be combined with all fungicides

Advisor's opinion

On wheat, the benefit of POLYVERSUM has not been demonstrated in trials conducted in recent years. On rapeseed, it is recommended to combine POLYVERSUM with a conventional fungicide at half dose. However, the POLYVERSUM + half-dose fungicide pack does not provide a significant efficacy gain compared to Propulse alone at 0.5 l/ha. Given the cost of the pack, its interest therefore seems limited.

Cost

20-27 €/ha

Sources

This article was written based on the document The fields of possibility in biological control in large-scale crops jointly written by François DUMOULIN, Hélène BAUDET, Gilles SALITOT and Inma TINOCO from the Chamber of Agriculture of Oise.

Appendices

Est complémentaire des leviers

S'applique aux cultures suivantes

Défavorise les bioagresseurs suivants