This work studied the effect of mineral and organic fertilization, fungicides, foliar fertilizers and plant extracts on the severity of onion leaf blight caused by Botrytis squamosa and onseedling quality. Field experiment was carried out at Epagri's experimental station in Ituporanga-SC from May to July 2005. In a split-plot design with four replicates the following treatments (factor A) were tested: a) control; b) fungicide ciprodinil (75 g a.i./100 L); c) potassium fosfite (00-30-20, 250 mL./100 L); d) foliar fertilizer (03-00-16, 400 mL/100 L); e) Bordeaux mixture (0.3%); f) Bordeaux mixture/potassium fosfite; g) extract of the alga Ulva fasciata (0.2%, dry weight: volume); h) field horsetail (Equisetum arwense) extract (0.26%) and i) Urtiga dioica extract (0.47%). Seedling beds were established under mineral or organic fertilization (factor B). Leaf necrosis area (%) was weekly evaluated and used to calculate the area under disease progress curve (AUDPC). Fertilizer type did not affect the development of leaf blight, but the mineral fertilizer increased both plant height and pseudostem diameter. While plant extracts were not effective, the application of fungicide, potassium fosfite, foliar fertilizer (03-00-16), Bordeaux mixture alone or combined with fosfite, significantly reduced leaf blight.
Allium cepa L.; Botrytis squamosa; disease management
