Yields and resistance of strawberry cultivars to crown and root diseases in the field, and cultivar responses to pathogens under controlled environment conditions.

Abstract

Devastating outbreaks of crown and root diseases have impacted severely on commercial strawberry production in Western Australia (W.A.). Studies were conducted to evaluate the yields, and resistance of three commercial strawberry cultivars to crown and root diseases, both in fumigated and non-fumigated field beds, and to determine the responses of eight commercial cultivars to individual pathogens under controlled conditions. In the field, cv. Camino Real showed the greatest fruit yield both in fumigated and non-fumigated beds, and was the most disease-resistant cultivar. Each cultivar had a greater fruit yield and a lower amount of plant decline in fumigated beds, compared with non-fumigated beds. Both for fumigated and non-fumigated beds, the amount of plant decline increased from August to November, particularly in non-fumigated beds. Under controlled conditions, cv. Festival was most resistant and cv. Camarosa most susceptible to wilt-causing Fusarium oxysporum . Against binucleate Rhizoctonia AG-A, Cylindrocarpon destructans and Phoma exigua , cv. Festival was most resistant and cv. Aromas most susceptible. Cultivar Camino Real was the most resistant to Gnomonia fructicola and Phytophthora cactorum and cv. Festival most resistant to Pythium ultimum . Against Macrophomina phaseolina , cv. Albion was the most resistant with cv. Camarosa the most susceptible. Cultivar Camarosa, the most widely grown cultivar in W.A., was most susceptible to F. oxysporum , while cv. Camino Real was resistant to F. oxysporum both in the field and the controlled environment conditions. Cultivar Festival is the most resistant cultivar to F. oxysporum and a range of different pathogens. The Australian bred cv. Juliette was as susceptible as cv. Camarosa to F. oxysporum, but relatively resistant to binucleate Rhizoctonia AG-A. This is the first study, not only to define the relative yield potentials of different cultivars in a situation where crown and root disease prevails in the field, but also to demonstrate differential resistance of current cultivars to specific pathogens associated with crown and root disease in W.A. For the first time, growers can now make informed choices about the cultivars they can deploy to minimise losses caused by diseases.