COMPARISON OF POWDERY MILDEW (Erysiphe cichoracearum) INOCULATION METHODS IN Cucurbita moschata

Powdery mildew (Erysiphe cichoracearum) limits pumpkin (Cucurbita moschata) production in Puerto Rico and other areas of the Caribbean. In order to effectively use half-sib family recurrent selection to develop polygenic mildew resistance we tested various inoculation methods to determine which method can best be used to quantify small differences in resistance. Dusting leaves using infected plant tissue was a fast and effective method that would be useful in a screening program where many genotypes need t4o be evaluated but where resistance need not be quantified. Spraying with a 1 x 10 spores/cc triton suspension was an efficient method for a recurrent selection program where small differences in resistance among families must be determined