Slow mildewing in Pumpkins: an opportunity to reduce Pumpkin yield losses caused by Erysiphe cichoracearum

Pumpkin powdery mildews, a disease caused by fungus Erysiphe cichoracearum, is one of the major diseases that reduce yield and quality of pumpkins. A field screening study involving fifty two pumpkin accessions was carried out at three powdery mildew hot spot sites in Malawi. The main objective was to assess the reactions of pumpkin accessions to E. cichoracearum. The experiment was laid out in a randomized complete block design replicated three times. Plot size was 3m x 3. 7m. There were statistically significant differences in apparent infection rates (P<0.001), area under disease progress curve, AUDPC (P<0.001), percent disease index, PDI (P<0.001) among the accessions across all sites. Pumpkin accessions 6 and 42 consistently showed slow rate of powdery mildew development at 4th, 6th, and 8th week after germination. A strong positive correlation (R= 0.7 at 8th week, and 0.97 at 12th week after germination) was observed between the number of rotten fruits and AUDPC. This study showed that out of the fifty two pumpkin accessions tested, none was immune to Erysiphe cichoracearum. However the accessions that recorded very slow rate of powdery mildew development showed high potential to maintain viable vines and support their fruits up to physiological maturity. We concluded that promoting slow mildewing pumpkin genotypes is appropriate solution to fruit yield and quality losses caused by E. cichoracearum.