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Report2022Peer reviewed

Microbial biocontrol agents in IPM strategies - reducing pesticide use in wheat and lowering the risk of fungicide resistance

Jensen, Birgit; Jørgensen, Hans J.L.; Collinge, David B.; Jensen, Dan Funck; Dubey, Mukesh; Karlsson, Magnus; Heick, Thies M.; Jorgensen, Lise N.


The main questions of the project were: (i) Can Septoria tritici blotch and Fusarium head blight be efficiently controlled by microbial biological control agents alone or combined with traditional chemical fungicides applied in low dosages? (ii) Can the development of fungicide resistance in the Z. tritici pathogen population be reduced by the combined use of microbial biological control and fungicides as compared to re-peated chemical fungicide applications? And (iii) can accumulation of mycotoxins in harvested grain be reduced by the use of microbial biological control agents? The project included three microbial biological control agents. The versatile fungal Clonostachys rosea, IK726, isolated from barley roots in Denmark and the two regis-tered bacteria-based products Cedomon (Pseudomonas chlororaphis, strain MA341) and Serenade ASO (Bacillus velezensis, syn. B. amyloliquefaciens, strain QST713). The azole fungicide Proline EC 250 (a.i. prothioconazole), belonging to the group of demethylase inhibitors, was chosen as a model fungicide in order to look for possible changes in fungicide sensitivity and mutations in the CYP51 gene of Z. tritici. In re-cent years, fungicide resistance to azoles in the Z. tritici population has developed in Denmark and the Nordic countries. The current study has not revealed any clear economic benefit, as only one of three trials gave a significant and positive yield increase with fungicide and biocontrol treat-ments. In order for biological control agents to provide attractive solutions, trial data should verify an economic benefit for the farmers in a range of 3-4 Dt/ha in order to pay for the cost of treatments.

Published in

Pesticide research
2022, number: 211ISBN: 978-87-7038-460-5Publisher: Danish Environmental Protection Agency