The aim of the present study was to develop a diagrammatic scale to assess gray mold caused by Amphobotrys ricini in castor bean (Ricinus communis L.). The experiment included 59 clusters, which were disinfected in solution of sodium hypochlorite to 2% for 30 seconds and distilled water and sterilized. Then, they were packed in moistened foam trays which received 5mm mycelial discs, and were kept in a climatic chamber at 25º C and 80%. RH. The disease evolution was observed daily pictures of the clusters diseased. To determine the severity percentage of the bunches, infected and healthy fruits were counted, estimating thus the percentage of the injured area, and developing a diagrammatic scale with six severity levels. The adoption of the proposed scale, improved the accuracy (R² = 0,94) "a" values were not significantly different from zero (0) and "b" values were not significantly different from one (1).
evaluation; severity; accuracy; precision
