Identification and pathogenicity of Botryosphaeria parva associated with grapevine decline in Kurdistan region - Iraq

Abstract

During a survey on fungi associated with decline symptoms on grapevine cultivars growing in Kurdistan region of Iraq, several isolates of Botryosphaeria species were encountered. All isolates were identified as Botryosphaeria parva Pennycook and Samuels. Pathogenicity test for isolate DKI 1 was performed on two cultivars, Taefi and Rashmew. Under greenhouse conditions, one-year grape rooted cuttings were inoculated with the pathogen isolate by two methods, injecting the spore suspension into the green shoots and by artificial inoculation of wounded shoots with mycelial mat. The highest canker length (15.0 mm) was produced after four months on the shoots of the Taife cultivar artificially inoculated with mycelial mat of the pathogen. Under field conditions, two methods of inoculation were adopted, wounding the green shoots and drilling a hole in the arms of mature vine, followed by inoculation with mycelial mat. The highest canker length (11.17 mm) was obtained after 5 months on wounded shoots of the Rashmew cultivar and with a significant difference from the Taefi cultivar. The pathogen caused a reduction in fresh and dry weight of green shoots and roots compared with the non-inoculated control. This is the first report on B. parva in Iraq.