Bicarbonate salts and calcium cyanamide suppress apothecial production by <i>Ciborinia camelliae</i>

Abstract

Apothecia of Ciborinia camelliae arise from soilborne sclerotia that are often located at the base of camellia bushes and release ascospores that infect camellia flowers To suppress the production of apothecia as a strategy to control camellia flower blight granule formulations of potassium bicarbonate (Armicarb 100SR) at 300 kg/ha ammonium bicarbonate (Armicarb 300) at 300 kg/ha and calcium cyanamide at 500 and 1000 kg/ha were applied to soil beneath camellia bushes After 16 days potassium bicarbonate ammonium bicarbonate and calcium cyanamide at both rates reduced the numbers of apothecia from 321/m² in untreated plots to 46 30 08 and 03/m² respectively This level of control continued for the duration of apothecial production Calcium cyanamide at 5001000 kg/ha and the bicarbonate salts at 300 kg/ha offer potential for cultural control of camellia flower blight The optimum rate for bicarbonate salts to achieve complete suppression of apothecia still needs to be determined