Prune out diseased tissue and destroy it. Spindly Shoots; Foliage Are Yellowed, Curled By Virus Diseases Various diseases caused by viruses occasionally attack zinnias. Spray with insecticides every few weeks to control sucking insects which spread the viruses. Serious infections cause the leaves to turn brown quickly and shrivel. You can apply powdered fox urine or blood meal around the foliage to repel rabbits from the plant. For example, an attack by bacteria is manifested by wet spots with yellow borders on the stem, blooms, and leaves of the Zinnias. Mosaic Virus. Zinnias are susceptible to a disease called bacterial leaf spot. As the spots become larger, they may develop dark concentric rings in the centers. Disease incidence is greater if plants are watered in the late afternoon or evening, thus causing the leaves to stay wet longer. The flowers of zinnia they exist in all colors except blue. Insecticidal soap sprays must be directed at the lower leaf surfaces where many pests feed. Pour alcohol or soapy water over trapped earwigs to kill them. For this reason, this article will help you to figure out what pests could be eating your precious plants. Stem and Root Rot Stem and root rot diseases cause black, mushy growth, and often kill zinnias. Nevertheless, it becomes heartbreaking when pests start to eat the leaves. These spots become brown or dark gray and wither, leaving holes in the leaves. Fungus grows best on damp foliage, so either water the plants with a dripper system or soaker hose, or if you’ve installed an overhead sprinkler system, water in the morning. Use pesticides only according to the directions on the label. Hi all , I have not come here for a long time. Just like bacterial leaf spot, when they become gray, they wither leaving holes in the leaves. zinniae) is a common disease, which occurs under conditions of extended leaf wetness.Penn State Dept. When to sow outside:RECOMMENDED. If your answer is yes, slugs are the pests eating your Zinnias. Discarded affected plant parts and keep the area around the plant neat. Purchase resistant varieties. That way, it won’t be difficult to identify the pest eating your Zinnias. Spray neem oil in the evening to avoid leaf burns during the day. The interesting fact is: it’s not difficult to identify them as the culprit because they are very greedy. Cercospora Leaf Spot: This fungal leaf spot, caused by Cercospora zinniae, occurs less commonly than Alternaria leaf spot, powdery mildew, or bacterial leaf spot, but it can be just as damaging. However, zinnias often carry powdery mildew and other diseases. Stems of these annuals will deteriorate over the winter, and we do not have research weighing their value for insects over the winter. Zinnias have few insect pests, but aphids, spider mites, and whiteflies may damage plants, especially during hot, dry weather. Join our mailing list to receive the latest updates from HGIC. Spray Zinnias with neem oil to control Japenese Beetles. I bought them and planted them about a week ago and they looked healthy. zinniae is the causal agent of bacterial leaf spot of zinnias, and the symptoms of infection are purplish spots that usually remain small, but they become angular in shape. 2. Ok. The holes bores are usually visible enough to notice the damage done to the plant. Zinnias grown as ornamental flowers are hybrid species derived from Z. elegans. Also, you will find the damage done to your leaves in the morning because slugs mainly feed when it is dark. Flower colors vary and include white, orange, yellow, pink, red, purple, and gold. See Table 1 for examples of insecticidal soap products. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Fungicide & Insecticide Products for Disease & Pest Control on Zinnias. Monitor for pests and diseases. Use natural predators such as parasitic wasps to keep away aphids from your Zinnias. Spray plants weekly with a copper fungicide following periods of leaf wetness to reduce disease incidence. ALTERNARIA LEAF SPOT OR BLIGHT It is also possible to find two-colored and mottled varieties. Pests & Disease: The biggest pests of zinnias are powdery mildew disease and Japanese beetles. Follow label directions for mixing and use. The center of these leaf spots may eventually tear, fall out, and leave behind holes in the leaves. Zinnias are either annual or perennial plants with colorful round flowers. Finally, rotate where you plant your zinnias (and all plants) each year so pests and diseases specific to that plant don't have a good chance to buildup in the soil over time. That means you may wake up one day and discover that only the stem of your plant is left behind. 3. Gather and destroy dead leaves and stems in the fall. This method works because the female parasitic wasps use Aphids as hosts to lay their eggs. As they feed, they inject the phytoplasma into the vascular system of the zinnia and cause the developing flowers to become deformed. Spray as needed following rainy periods with chlorothalonil, copper fungicides, or mancozeb. Follow all directions, precautions and restrictions that are listed. However, if fungicides are required, there are several that are very effective. Pests and diseases on Zinnias Old zinnia plants are susceptible to fungal disease, although they will still bloom successfully if affected. These spots may coalesce (run together), and heavily infected leaves usually die. The most common problem for zinnias is powdery mildew. Do the spraying early in the morning to allow the water to dry early and prevent mildew. Eventually the leaves turn yellow and drop. When to start inside:4 to 6 weeks before your average last frost date. College of Agriculture, Forestry and Life Sciences, Centipedegrass Yearly Maintenance Program, Ferti-lome Horticultural Oil Spray Concentrate, Bonide Insecticidal Soap Concentrate; & RTU, Spectracide Immunox Multi-Purpose Fungicide Concentrate, Bonide Sulfur Plant Fungicide (dust or spray), Bayer BioAdvanced Disease Control for Roses, Flowers & Shrubs Concentrate, Cleary’s 3336-WP Turf & Ornamental Fungicide. Follow label directions for mixing and use. Zinnias can be susceptible to fungal diseases, especially powdery mildew. See Table 1 for examples of brands and products. This is the best strategy for avoiding powdery mildew. Thus, zinnia does … Remove plants after they are killed by frost in fall to avoid disease issues the following year. Check with your local Cooperative Extension Service for pest controls recommended for your area. Can anyone tell me what is wrong with my zinnias? Bacterial and fungal spots, powdery mildew, and bacterial wilt may affect zinnias. Additionally, organic pellets containing ferric phosphate are effective slug repellant. These sap-sucking insects love to suck the juice from the Zinnias plant by boring holes into the leaves and stems. Spray plants following rainy periods, as rainy conditions increase disease occurrence and spread. Fortunately, aster yellows is not extremely common. Name: Lily (Zone 11) cornflower Nov 6, 2016 8:39 AM CST. Seed collected from infected plants may spread bacterial leaf spot. Barbara H. Smith, HGIC Horticulture Extension Agent, Clemson UniversityJoey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University. Integrated Pest Management Strategies. They ravage the foliage, remaining only skeleton-like leaves. Zinnia Pests & Diseases. Although most research proves that rabbits don’t like Zinnias, they may still munch on the plant for the fun of it. At the end of this season, remove ALL plant tissue from these plants, and dispose of them in a method other than composting. See Table 1 for examples of brands and products containing these fungicides. Likewise, fungal infections are manifested by large, round spots on the leaves of the zinnias. Alternaria blight is the most common and conspicuous. Pick out slugs as soon as you notice them. See Table 1 for examples of brands and products containing copper. Informational table showing disease name, symptoms, pathogen/cause, and management of Zinnia diseases. Zinnia or Zinnia, a beautiful flower. Which Foods Should I Select to Promote Health? See: Zinnia-Bacterial Leaf Spot. These zinnias have become infected with powdery mildew (Golovinomyces cichoracearum).Mary Ann Hansen, Virginia Polytechnic Institute & State University, Bugwood.org. COVID-19 Extension Updates and Resources ... More Information », Factsheet | HGIC 2110 | Published: Nov 9, 2020 | Print, Zinnias are excellent sources of pollen and nectar for many beneficial insects; therefore, it is not recommended that insecticides, other than insecticidal soap, be used to control damaging mite and insect pests.Barbara H. Smith, ©2019 HGIC, Clemson University. Deer scat is different from rabbit droppings, so look for paw prints and scat to identify the pest. Some may have distinct markings or blotches. Usually, they bore tiny holes into the Zinnias leaves and flowers. Views: 5748, Replies: 9 » Jump to the end. If you find a metallic green insect with cooper brown wings, feeding on your Zinnias, that is most likely a Japanese Beetle. Insect Pest Prevention & Control: Zinnias are excellent sources of pollen and nectar for many beneficial insects; therefore, it is not recommended that insecticides, other than insecticidal soap, be used to control damaging mite and insect pests. More often than not, diseases and infections in zinnia plants happen mainly because of insects. In the people these flowers are known as majors. Caterpillars, mealybugs, and spider mites also cause problems. Make sure not to compost them; otherwise, you run at a risk of infecting other susceptible plants with the pathogens. Destroy infected plant. Table 1. It is carried by aster leafhoppers (Macrosteles quadrilineatus), which are insects that feed on the sap of the plants. Alternaria blight is the most common and conspicuous. Japanese Beetles could be the insect that eats your Zinnias. Do not use thiophanate methyl fungicides, as these are ineffective. 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