Hibiscus flowers steal the show throughout the summer, even though each bloom only lasts for one or two days. Although Hibiscus plants don’t suffer from many problems, they’re still vulnerable to certain diseases and pests. In this article, we’ll look at nine common hibiscus pests and diseases and how to tackle them.
9 Common Hibiscus Pests and Diseases
Aphids are common sap-sucking garden pests that target hibiscus plants. These tiny black or green insects excrete honeydew, a sticky substance that encourages the growth of sooty black mold. Misshapen or stunted growth is another symptom of an aphid infestation.
Aphids congregate underneath leaves and along stems. Use a hose to remove large numbers of aphids quickly. Alternatively, use biological controls, insecticidal soap, or horticultural oils like neem oil.
2) Botrytis Blight
Botrytis blight is a common fungal disease often called gray mold after the growths that appear on infected plants. Large spots that turn from brown to black may also appear on flower buds.
Botrytis blight loves humid conditions, so provide good air circulation by leaving enough space between your hibiscus and other plants. Remove any infected parts of your hibiscus and burn them to stop the disease from spreading.
3) Japanese Beetles
Japanese beetles are annoying pests that eat hibiscus leaves and flowers. Adults have brown bodies with metallic green heads and lay their eggs in the soil. The larvae start to eat nearby roots once they hatch.
Pick off adult Japanese beetles and drown them. Use Japanese beetle traps to lure these pests away from your hibiscus. You can also eliminate them using horticultural oils or insecticidal soap.
4) Leaf Spot Diseases
Leaf spot diseases are common fungal infections that can impact hibiscus plants and thrive in warm, humid conditions. Yellow or black spots appear on infected leaves. Grayish-white fungus may develop on the undersides of infected leaves.
Leaf spot diseases interrupt photosynthesis, causing your hibiscus to produce weak or stunted growth. Eliminate leaf spot diseases using organic fungicides and give your hibiscus plants plenty of space to promote good air circulation.
Mealybugs are slow-moving, sap-sucking insects with oval-shaped bodies covered in white wax that can impact hibiscus plants. Symptoms of a mealybug infestation include clumps of fluffy white wax and weak or stunted growth. Mealybugs also produce honeydew, which can lead to the appearance of sooty black mold.
Mealybugs cause hibiscus plants to produce weak or stunted growth. Treat them using insecticidal soap or horticultural oils. You can also use biological control methods like mealybug destroyers.
6) Powdery Mildew
Powdery mildew is a common fungal disease that can infect hibiscus plants. Symptoms of powdery mildew include powdery white growths on hibiscus foliage and curled or discolored leaves. Powdery mildew can also cause stunted growth.
Powdery mildew thrives in humid conditions, so avoid overwatering your hibiscus. Promote good air circulation by leaving plenty of space around your plants. Remove infected leaves and any leaf debris around your hibiscus.
7) Scale Insects
Scale insects are another type of sap-sucking pest that can infest hibiscus plants. Scale insects are small bugs with waxy armored shells that can be spotted crawling over leaves. Symptoms include deposits of honeydew, sooty black mold, and white eggs on the undersides of leaves.
Get rid of scale insects using insecticidal soap or horticultural oils. Use biological controls or organic pesticides to eliminate large-scale insect infestations.
Whiteflies are small white-flying insects closely related to aphids. Whiteflies feed on sap and excrete deposits of honeydew that can lead to the growth of black sooty mold. Other symptoms include yellowing or wilting leaves on hibiscus plants.
Eliminate whiteflies using biological controls, insecticidal soap, and horticultural oils. Use a hose to dislodge eggs and adults from your hibiscus. Whiteflies thrive in warm weather, so be vigilant during the summer.
9) Wilt Disease
Wilt disease is a fungal infection caused by fungi entering your hibiscus through the roots. These fungi impair your hibiscus’s ability to circulate water properly. Wilt disease affects the entire plant, causing wilting, dying leaves that turn dark green or black rather than yellow.
Mist the leaves of your hibiscus daily until the leaves look healthy and new growth appears. In some cases, the disease can’t be stopped, which unfortunately means you’ll have to dispose of your hibiscus.
Hibiscus Pests and Diseases FAQs:
What are the most common pests that affect hibiscus plants?
The most common pests affecting hibiscus plants include aphids, spider mites, whiteflies, and thrips.
How can I tell if my hibiscus plant has a pest problem?
Signs of a pest problem on a hibiscus plant can include discolored or distorted leaves, sticky residue on the leaves or stems, webs, or insects on the plant.
What are some of the diseases that hibiscus plants can be susceptible to?
Hibiscus plants can be susceptible to diseases such as powdery mildew, leaf spot, root rot, and bacterial blight.
How can I prevent pests and diseases from affecting my hibiscus plant?
Keeping your hibiscus plant healthy with regular watering and fertilization, removing dead or diseased plant material, and keeping the area around the plant clean and debris-free can help prevent pest and disease issues.
What are some natural ways to control pests on my hibiscus plant?
Some natural pest control methods include spraying the plant with water and dish soap, using neem oil, or introducing beneficial insects such as ladybugs or lacewings.
How can I treat a hibiscus plant that a disease has infected?
Treatment for a diseased hibiscus plant will depend on the specific disease, but some options can include removing infected plant material, applying fungicides or bactericides, or adjusting watering or fertilization practices.
What are some signs that my hibiscus plant may be suffering from a nutrient deficiency instead of a pest or disease issue?
Signs of nutrient deficiency in hibiscus plants can include yellowing leaves, stunted growth, and smaller or fewer flowers.
How often should I inspect my hibiscus plant for signs of pests or disease?
In my experience, inspecting your hibiscus plant at least once a week for signs of pests or disease is a good idea.
Can hibiscus pests or diseases spread to other plants in my garden?
Yes, hibiscus pests or diseases can potentially spread to other plants in your garden if not adequately controlled.
Should I be concerned if my hibiscus plant drops its leaves or flowers suddenly?
Sudden leaf or flower drop can be a sign of stress on the plant, which could be caused by factors such as over or under-watering, pest or disease issues, or environmental factors. It’s essential to identify the cause of the stress and address it to prevent further damage to the plant.
Hibiscus flowers can be vulnerable to pests like aphids, mealybugs, or diseases such as gray mold or wilt disease. Treat diseases with organic fungicides and eliminate pests using horticultural oils and insecticidal soap. Provide ideal growing conditions to reduce the risk of pests and diseases in the future.
For more, see our in-depth guide to troubleshooting non-flowering hibiscus plants, common causes of yellow leaves on hibiscus, and 32 amazing uses and benefits of hibiscus plants.
Edd is a budding content writer and gardener living in the United Kingdom. He has a bachelor's degree in Creative and Professional Writing and has written for several gardening publications online. He is passionate about nature and sustainability with a focus on gardening and wildlife.
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