Iris Borer Description: Eggs overwinter in stems of iris and other debris. After eggs hatch they must crawl to the base of the iris to bore into stems. During this migration they are susceptible to Grub-Away Nematodes. Infested leaves are yellow from the tip back, have notches on the edge; plants lose vigor; many fail to bloom. Solution: Grub-Away Nematodes are the only effective control; soak bottom portion of stem and soil. Keep soil moist for first week.