Luis Sánchez A.1 y L. G. Weathers2

The periods of greatest susceptibility of sunflower to Sclerotinia sclerotiorum (Lib.) De Bary, durin its growing cycle were determined.
Sunflower plants were inoculated with the funges every 8 days from the 5 pair leaf stage until full nature using infected toothpicks.
The tests were conducted both under field and greenhouse conditions.

1Ing. Agr. MS, Estación Experimental Agronómica y Profesor de Fruticultura, Facultad de Agronomía, Universidad de Chile, Casilla 1004, Santiago, Chile.
2Ph D, Profesor de Patología Vegetal, Universidad de California, Riverside, California.