Daylilies, Hemerocallis sp., are quickly becoming one of the most popular garden perennials. No longer are they confined to the roadsides, they are the centerpieces of gardens. Daylilies come in many different colors and in a multitude of shapes and sizes. They are edible and considered to be relatively pest and disease free. However, two of the most serious fungal diseases of daylilies are leaf streak caused by Aureobasidium microstictum and leaf rust caused by Puccinia hemerocallidis.
To determine the over-wintering capability of P. hemerocallidis two field trials were conducted at The Ohio State University's Waterman Agricultural and Natural Resources Laboratory, Columbus, Ohio. Results from these trials indicate that P. hemerocallidis will not over-wintering in central Ohio.
To learn how to better control leaf streak, several experiments were carried out. First, a variety trial looked for resistance among 415 different varieties of daylilies. Mean percent leaf area affected and various traits of the daylilies, such as ploidy, growth habit, height class, breeder, and year introduced were analyzed. Survival was also recorded and analyzed based on ploidy and growth habit. Tetraploid daylilies were found to have a significantly higher survival rate than diploid daylilies, while no significant difference was found based on growth habit. No significant difference in mean percent leaf area affected was found based on height class, growth habit, ploidy, or year of introduction. A significant difference in mean percent leaf area affected was found based on breeder.
Second, a field-conducted fungicide trial examined control of leaf streak by five different fungicides, Triact 70®, Phyton 27®, Fungo 50®, Heritage®, and Eagle®, on five different daylily cultivars, 'Aztec Gold', 'Pardon Me', 'Little Grapette', 'Happy Returns', and 'Hyperion', in a split plot design. Phyton 27®, Fungo 50®, Heritage® and Eagle® controlled leaf streak significantly better than Triact 70® and the untreated control treatment. 'Hyperion', 'Little Grapette', and 'Happy Returns' were found to be significantly more resistant than 'Aztec Gold' and 'Pardon Me'.
Finally, a third experiment assessed the effect of nitrogen on leaf streak symptom development in a greenhouse trial. No significant difference in lesion length based on nutrient treatment was found. Daylilies treated with 200 ppm N and 100 ppm N were found to produce significantly more leaves than those treated with 0 ppm N.