Pathogens associated with blueberry cutting failure in south Georgia nurseries and their control

Abstract

n 2007 and 2008, a survey of 18 blueberry propagators in south Georgia was conducted to determine the incidence of soilborne plant pathogens and the prevalence of propagation practices currently used. There was little consistency in propagation methods across nurseries, documenting a need for developing standardized best practices. Across 204 symptomatic blueberry cuttings sampled during four survey dates, 15.2, 4.9, 1.0, and 16.7% harbored species of Cylindrocladium, Rhizoctonia, Oomycetes, and Fusarium, respectively, although the pathogenicity of Fusarium remains to be confirmed. A link was established between propagation media reuse and presence or absence of Cylindrocladium. Fungicide efficacy trials were conducted on cuttings planted in propagation medium infested with Cylindrocladium parasiticum or Rhizoctonia sp. Fludioxonil proved to be the most effective against Cylindrocladium, whereas fludioxinil, flutolanil, and azoxystrobin were effective against Rhizoctonia. This survey provides the groundwork for future standardized recommendations for propagating diseases-free blueberry cuttings.