There is only one generation a year of the gall midge, so as the year progresses you should find the later flowering daylilies are less and less affected as the midge life cycle winds down and they start to pupate for the next year's hatch. That's why people in areas where the gall midge occurs are often advised to concetrate on the later flowering daylily cultivars which avoid the midge, rather than the early ones that coincide with the midge's activities.
