However, a distinguishing symptom with daylily rust is the appearance of small orange pustules that develop on the lower surface of leaves. of Plant and Environmental Sciences, Clemson UniversityClyde S. Gorsuch, PhD, Emeritus Faculty, Entomology, Clemson University, Joey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University. To control leaf streak the fungicide thiophanate-methyl or myclobutanil may be applied to slow disease development and to protect susceptible new growth from infection. Two-spotted Spider Mites (Tetranychus urticae): The two-spotted spider mite and other mite species can be a problem on daylilies. If this document didn’t answer your questions, please contact HGIC at [email protected] or 1-888-656-9988. ; & RTS, Bonide Mancozeb Flowable with Zinc Concentrate, Spectracide Immunox Multi-purpose Fungicide Concentrate, Bonide Eight Insect Control Vegetable, Fruit & Flower Concentrate, Bonide Colorado Potato Beetle Beater Concentrate, Bayer Advanced 3-in-1 Insect, Disease & Mite Control Conc. Because of the evident plant root galling by the root-knot nematode, entire plant samples should be submitted, not soil samples for assays as for other soil nematodes. Leaf Streak: Daylily leaf streak is caused by the fungus Aureobasidium microstictum. Table 1. Control: Remove their daytime hiding places by removing mulch and leaf litter near the base of the plant. Aphids: Various aphids can be pests on daylilies. There may be several contributing factors to this daylily issue including bulb mites and leaf streak fungus. The use of a slow-release fertilizer is preferred. However, be aware that some nutrient deficiencies cause streaking in leaves and flowers. Joey Williamson, ©2015 HGIC, Clemson Extension. Blue sticky traps will help protect daylilies from thrips. Daylily Rust: Daylily rust is caused by the fungal pathogen Puccinia hemerocallidis. With a light infestation, daylily leaves and flowers develop yellowish speckles. Aphids are soft-bodied insects that vary in color from yellow-green to almost black. Two-spotted Spider Mites (Tetranychus urticae): The two-spotted spider mite and other mite species can be a problem on daylilies. According to AHS, spring sickness occurs in early spring with daylilies showing discolored, twisted, bent, or stunted foliage on some of the daylily’s fans. Flower thrips are small, dark-colored insects that suck sap from the plant by scraping into the surface of plant cells. They feed on leaves and flower buds by inserting their mouthparts and sucking plant sap. If a single aphid survives, a new colony can be produced in a short period of time. Removing nearby weeds before spring growth is an important step in the control of spider mites. Leaf streak is a fungal disease that's usually mistaken for poor nutrition and often ignored. Sampling: As a result of their small size, thrips are difficult to detect before damage is obvious. Daylily leafminer damage is more aesthetic, but not extremely significant to plant health. They are very small, less than 1 / 50 -inch long. The leafminer adult is a small black fly, which oviposits (lays) its eggs on daylily foliage in the spring. These symptoms usually develop from the leaf tip downward. These pustules produce the yellowish-orange urediniospores that spread to infect additional daylily foliage. They are typically more of a problem during cool weather in the spring. All recommendations are for South Carolina conditions and may not apply to other areas. The small pale-yellow larvae then feed within the leaves in meandering mines that become wider as the larvae grow. As with any pesticide, read and follow all label directions and precautions. Both adults and nymphs (immature insect stage resembling the adult, but smaller) feed by scraping surface cells to suck plant sap. Recovery and normal blooms occurring that season are uncertain. Along with leaf decline, growth is stunted. Prevention & Treatment: Inspect and purchase disease-free plants, especially the lower leaf surfaces. Symptoms are elongated yellow streaks along the leaf mid-vein followed by browning, or spots on the infected leaves with yellow borders. Discard all infected plant material. Check for and plant resistant cultivars. Do not spray chlorothalonil during blooming period. To avoid killing these beneficial insects, which naturally reduce thrips populations, insecticides should be avoided as much as possible. Remove and dispose of infested plants, but do not add them to the compost pile. Examples of resistant daylily cultivars include: Betty Bennet, Edna Spalding, Ella Pettigrew, Globe Trotter, Nancy Hicks, Pink Superior, Ron Rousseau, Sudie, Tropical Tones, Upper Room, and Winsome Lady. They have piercing mouthparts that allow them to puncture plant tissue and suck plant sap. When they feed on flower buds, the flower may die without opening. Prevention & Treatment: To prevent soft rot, avoid poor soil drainage by amending heavy clay soils with organic matter (such as with composted pine bark or compost), avoid poor air circulation conditions in plant areas, avoid problem planting sites (do not plant susceptible daylily varieties in the same spot where plants show soft rot symptoms), permit wounded plants to heal (cork over) before planting, and do not fertilize or water too much. Maggots develop inside daylily flower buds causing them to become inflated, distorted and unable to open properly. In the right column are the probably causes of those symptoms. This pest over-winters as small tan pupae, approximately the size of a grain of rice. To help with your bud blast care, the most common environmental problems are listed below, along with solutions for treating bud blast: Improper Watering – Improper watering causes a great deal of stress to many plants. Join our mailing list to receive the latest updates from HGIC. The feeding activities of the larvae inside the buds cause abnormal bud development and these buds … They are very small, less than 1/50-inch long. Bacterial soft rot, also known as crown rot, is caused from damaged roots or crowns and occurs in... Slugs and Snails. The appearance of shiny, slimy trails is a typical sign of their presence. With severe infestations, leaves and flowers are stunted and distorted and may turn brown and die. Their feeding results in ragged notches along leaf edges and sometimes holes in the middle of leaves. Daylilies prefer a well-drained soil with adequate organic matter. Apply environmentally safe snail and slug baits (containing iron phosphate) near the beds. Early flowering daylilies are typically the most heavily infested and egg-laying may have ceased by the time later flowering daylilies … If rust-infected foliage is wiped with a white tissue, the spores will rub off and are visible as a yellowish-orange stain. This means it will penetrate the foliage to kill the larvae within the leaves. For more severe infestations, tau-fluvalinate or bifenthrin sprays will control spider mites. Prevention & Treatment: If root-knot nematodes are suspected in residential landscape beds, plant samples may be submitted to the Clemson Plant and Pest Diagnostic Clinic through any county Clemson Extension office for verification. Daylily leaf streak may be avoided by purchasing disease-free stock plants and propagating only from healthy specimens. With a heavy infestation, the speckles will run together and entire leaves can become bleached and die. Daylily Leafminer: The daylily leafminer (Ophiomyia kwansonis) was introduced into the US around 2006 from Japan and Taiwan, and has quickly spread over the Eastern US. Under watering may cause plants to redirect water from enlarging buds to food-producing areas in an act of self-preservation. Flower Thrips (Frankliniella tritici): Flower thrips and various other thrips species are serious pests of daylilies. See Table 1 for examples of products. Daylily rust is capable of spreading quickly. Joey Williamson, ©2015 HGIC, Clemson Extension. As with all pesticides, read and follow all label directions and precautions. Spray at 2-week intervals as needed, and also after cutting back plants. Over-wintering occurs either near the base of the leaves or at the base of the plants. Make 3 or 4 applications at 2-week intervals. Control: Several naturally occurring enemies feed on aphids, including green lacewings and ladybird beetles (ladybugs). If serious damage is occurring, insecticidal soap or spinosad sprays are recommended. See Table 1 for examples of brands and products. Daylily leaf streak is caused by the fungal pathogen Aureobasidium microstictum. To aid in control of daylily rust, plants may be sprayed with propiconazole, myclobutanil or chlorothalonil. Root-Knot Nematode: Root-knot nematodes (Meloidogyne species) can cause loss of vigor and severe decline of daylilies. Control: Spider mites overwinter (survive the winter) on weeds, such as chickweed. In the fall, remove dead foliage from around the base of the plants and dispose of the clippings, as the fungus will over-winter on senesced foliage, and spores will be produced the next spring to infect new leaves. As a result of their phenomenal reproductive rate, aphids are very difficult to control with insecticides.