Evaluation of disinfectants, algicides, and fungicides for control of orange cane blotch of blackberry in the field

• Published in: Crop protection Vol. 122; pp. 112 - 117
• Main Authors: Browne, Frances B., Brannen, Phillip M., Scherm, Harald, Taylor, Jeremy R., Shealey, Justin S., Fall, Leigh A., Beasley, Edward D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2019
• Subjects: Blackberry; Cephaleuros virescens; Chemical control; Orange cane blotch; Orange felt; Rubus; Orange cane blotch; Blackberry; Orange felt; Cephaleuros virescens; Rubus; Chemical control
• ISSN: 0261-2194; 1873-6904
• DOI: 10.1016/j.cropro.2019.04.019

The alga Cephaleuros virescens causes orange cane blotch (OCB), a serious disease of blackberry in the southeastern United States. Field efficacy trials with diverse algicides, disinfectants, and fungicides were conducted over a 3-year period at two locations on ‘Ouachita’ thornless blackberry. Foliar treatments, applied as multiple sprays during the summer and fall, included ametoctradin + dimethomorph, calcium polysulfide, calcium polysulfide + surfactants, captan, chlorothalonil, copper hydroxide, copper hydroxide + hydrogen dioxide, fluazinam, fluopicolide, hydrogen dioxide, mancozeb, mancozeb + copper hydroxide, mandipropamid, mefenoxam, mefenoxam + copper hydroxide, mefenoxam + mancozeb, potassium phosphite, potassium phosphite + captan, potassium phosphite + copper hydroxide, oxathiapiprolin and diluted sodium hypochlorite. Potassium phosphite was the only active ingredient that provided consistent and significant disease suppression. Management of OCB will be difficult in light of the limited number of labeled applications of potassium phosphite allowed and the potentially long infection period of the pathogen.
•Alga Cephaleuros virescens causes orange cane blotch of blackberry.•Potassium phosphite found effective for suppression.•Management is difficult due to limited labeled applications of potassium phosphite.