Control of Dieback, Caused by Eutypa lata, in Red Currant (Ribes rubrum) and Gooseberry (Ribes uva-crispa) in the Netherlands

Over decades, growers in the Netherlands have problems with a disease that causes dying branches and stem cankers in red currant. For many years it was assumed that this disease was related to fungi such as Nectria cinnabarina, Phomopsis spp. and the insect Synanthedon tipuliformis. However, recently it was found by Applied Plant Research and the Plant Protection Service that the causal organism is the fungus Eutypa lata. The disease is considered of major economic importance, especially as red currant growing is rapidly expanding in the Netherlands. E. lata was identified with three detection methods (visual, plating and DNA). Symptoms of E. lata do not usually appear until currant plants are at least three to four years old. These cankers are always associated with old pruning wounds. Eventually, the entire branch is killed. High disease incidences and annual losses of 10% to 30% of the productive branches are reported. In some cases entire fields have to be replanted. E. lata is well known as one of the most destructive diseases of grapevines (Vitis vinifera). The importance of this disease in currant growing was not known. Research is focusing on the evaluation of control measures; e.g. chemical and biological control treatment of pruning wounds, and disease management such as sanitation practices. Also, the epidemiology of E. lata is studied. High densities of ascospores of E. lata were found in a spore trap placed in a red currant field in the Netherlands. In the subsequent field survey fruiting structures (stromata) and ascospores were found on dead infected red currant wood.