CONTROL STRATEGIES FOR COLLETOTRICHUM ACUTATUM ON STRAWBERRIES IN NORTH ITALY

Studies were conducted during three fruiting seasons on anthracnose susceptible cv. ‘Onda’ (first year) and cv. ‘Alba’ (second and third year) strawberry cultivars in the Romagna Region of Italy.
In the spring, four and two weeks before bloom, the plants were inoculated by spraying each plant with a 10 ml-volume of a C. acutatum conidial suspension (10⁶ conidia ml^-1). To test the in vivo efficacy of a newer fungicide compared with older ones used in conventional spray programs the following fungicides were used: a combination of cyprodinil (37.5% a.i.) and fludioxonil (25% a.i.) (trade name Switch^®) at 0.8 kg ha^-1; a combination of boscalid (26.7% a.i.) and pyraclostrobin (6.7% a.i.) (trade name Signum^®) at 1.8 kg ha-1; azoxystrobin (23.2% a.i.) (trade name Ortiva^®) at 0.9 l ha^-1. Two treatments were applied: the first a week before full-bloom and the second at the full-bloom stage.
The timing of Signum^® fungicide application was also evaluated in the same fields but in another batch of fruits inoculated with C. acutatum as described above.
Berries were harvested in threefold, examined and categorized as marketable or diseased fruit.
Marketable fruit was stored for 2 days at 2°C and another 3 days at 20°C and examined at each time interval.
Treatments with pyraclostrobin+boscalid or cyprodinil+fludioxonil lead to higher marketable yields, significantly reducing the infections with respect to controls in all years, with an efficacy ranging from 50% to 81%. Azoxystrobin reduced the infections significantly with respect to controls but less effectively than pyraclostrobin+boscalid and cyprodinil+fludioxonil.
Two applications of Signum^® during bloom were able to control anthracnose, although only one treatment near harvest may be useful when weather conditions are favourable to C. acutatum development.

VI International Strawberry Symposium

M. Mari, S. Gengotti, G. Ceredi, L. Antoniacci, C. Montuschi, E. De Paoli

Fragaria × ananassa, anthracnose, disease control, fungicide, shelf-life

https://doi.org/10.17660/ActaHortic.2009.842.53