The effects of barley and common vetch on Verticillium wilt intensity were examined at Nazilli Cotton Reserach experiment fields during 2006-2007. Applications used in experiment were planted as barley, barley+common vetch, common vetch (traditional production), common vetch (growing at last irrigation) and control (conventional cotton production). After a four weeks residue decomposition period, seeds of Nazilli 84-S cotton variety were planted in a randomized complete block design with four replications. The data for disease intensity were determined during the stage of 5-10%, 50-60% cotton boll opening and after harvest. Seed cotton yield and fiber quality properties were also determined. Disease intensity identified according to symptoms on leaf and cross section of stems was determined lower level in organic growing plots and it was followed by control growing plot. During experiments, green manure applications of barley and barley+common vetch provided with a larger decrease on disease intensity than control growing plot. This also shows that cotton growing increase disease intensity every year. In common vetch and control plots, average yield values were determined higher according to barley+common vetch and barley growing plots. Cotton fiber properties have not been affected by these treatments.
