GreenCast validation of anthracnose (Colletotrichum graminicola) on golf greens in the Nordic region

Summary

Anthracnose is a stress-related disease on golf greens with Poa annua or Agrostis stolonifera as the dominant species. As for other diseases, Integrated Pest Management principles require that pesticides for control of anthracnose should only be applied according to monitoring in the field or to disease forecasts or early warning methods.

In this project, GreenCast (GC) predictions for anthracnose were validated from 1 June-1 Nov. 2014 on a Poa annua green at Bioforsk Landvik, Norway. The turf was mown to 3 mm three times per week, fertilised weekly with total N per season of 27 g m^-2, irrigated to field capacity twice per week and subjected to wear corresponding to 24 000 rounds of golf per year. Headway (propiconazole+azoxystrobin) was applied at a rate of 3 L ha^-1 according to the following criteria (treatments):  (1) Unsprayed control; (2) GC-Some risk; (3) GC-Medium risk; (4) GC-Medium/high risk; (5) GC High risk;  (6) First application at GC-Medium risk, then at GC-High risk; (7) First sign of disease and (8) Prophylactic. After one application, the turf was considered protected for 28 days before the next application according to the same criteria. Visual turf quality and percentage of plot area affected by antrachnose were assessed at weekly intervals.

The first application according to ‘First sign of disease’ (treatm. 2) was made on 10 June, one week after the prophylactic treatment. During the entire season, these treatments were sprayed 5 and 6 times, respectively. ‘GC-Some risk’ resulted in 2 applications (10 July and 7 Aug.), ‘GC-Medium risk’ in one application (23 July), and ‘GC-Medium/High’ and ‘GC-High risk’ in zero applications. Anthracnose on unsprayed control plots showed the first outbreak from <0.1 to 1.4 % of plot area between 25 June and 3 July and increased rapidly from 3 to 7 % of plot area  during an exceptionally warm and dry period from 22 July to 5 Aug. GreenCast failed to predict the first outbreak, but issued a medium risk warning before the warm, dry period. As a result, plots sprayed on 23 July (treatments 4 and 6) had significantly less anthracnose and better turf quality in August and early September than unsprayed plots.  

In conclusion, it seems that GreenCast has some merit in predicting the risk of increased anthracnose during warm and stressful periods, but the model needs refinement in order to predict the first and less visible increases that occur when the disease is still affecting less than 1% of the green area.  

Fundings (kSEK)

Project participants

Tatsiana Espevig

Researcher

Norwegian Institute for Bioeconomy (NIBIO), Department for Urban Greening and Environmental Technology, Turfgrass Research Group, Landvik, Reddalsveien 215, 4886 Grimstad, Norway.

+47 406 23 778

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