Perennial flax is rarely bothered by insects and disease. Mentioned below are two occasional insect pests.
Plant Parts Eaten Away By Grasshoppers
Grasshoppers commonly visit residential yards and gardens as well as roadsides and rural fields. Occasionally they become a major pest of ornamental plantings. This usually happens when the weather, such as a series of warm dry summers, creates favorable conditions for their reproduction. (Cool, wet weather with extended periods of high humidity discourages them). Typically grasshoppers eat indiscriminately, devouring any and all plants in the area. Rarely do they appear in large enough numbers to cause major problems for homeowners. Control them by keeping weeds down. Spray visible hoppers with neem oil soap or insecticidal soap. In the event of a major infestation spray them with a pyrethroid insecticide. Read product labels and follow the directions carefully. Do not spray insecticides indiscriminately around the landscape. For more information see the file Controlling Grasshoppers
Stems Cut Off At Soil; Leaves, Blooms Eaten By Cutworms
Cutworms are actually the larvae, or worm form, of a certain moth. They hatch from eggs laid in grass and weeds, then burrow into the ground from which they emerge to feed at night on nearby plants. Sometimes they crawl up plants and chew on the leaves and blossoms. They are tough to combat because they live underground and work at night. Keep the area clear of grass and weeds. If problems with cutworms are extensive, it may be necessary to use an insecticide. Choose a product containing a pyrethroid insecticide. Read the label carefully and follow the instructions for use against cutworms. Take all recommended precautions. For more information see the file Controlling Cutworms