Hibiscus Problems?
Lately, several local gardeners have been reaching out about their hibiscus plants being devastated by a disease or fungus while I’ve been working the Brevard County Master Gardener Help Desk. After checking out photos and listening to the symptoms, I’ve found the culprit isn’t a disease or fungus. It would appear that the Pink Hibiscus Mealybug has been munching on their plants - mainly their hibiscuses.
Feeling a little paranoid about your garden pests? I’m going to walk you through what the Pink Hibiscus Mealybug is, what the symptoms are, and the best ways to get rid of this bad guy!
What are Pink Hibiscus Mealybugs?
Florida hasn’t always had Pink Mealybugs, Hibiscus Mealbugs, or the most common name - Pink Hibiscus Mealybugs (PHM), snacking on our residential and agricultural plants. In 2002, these pests were discovered in South Florida and now they’ve been spotted in over 30 counties throughout the state. Tropical and subtropical fruit, vegetables, and ornamental plants can all be a host to the PHM, but the hibiscus seems to be their favorite. Gardeners across Florida have seen them severely infect and kill hibiscus trees and bushes. Hints the name.
Pest Investigation
Look for a mass(s) of white, waxy substance on your plant’s flower buds, fruit, leaves or branches. I’ve had local gardeners say their hibiscus leaves appeared contorted, twisted, or curled and/or new hibiscus buds never reaching their full bloom. Which really stinks! These symptoms are from the bug’s toxic saliva that is left behind after eating the leaves or the unopened flower bloom. From reading various University of Florida/IFAS articles, I found PHM most commonly like to attack the ornamental parts of flowers.
The two images above are from a friend’s garden in Indian Harbour Beach, Florida. You can see the damage Pink Hibiscus Mealybugs have done to her hibiscus bushes. Notice the white, waxy substance and the devastated hibiscus bloom.
Natural PHM Rx
So sorry if I ruined your appetite with those last few details, but let’s move on to solutions to get rid of this hellacious pest! Let’s say your plant is minimally infected - meaning it’s not a full takeover. Prune that one area of that plant/hibiscus with shears or clippers. Then, immediately place those infected plant clippings into a garbage bag and dispose of in your residential trash (NOT yard waste) to prevent the infestation from spreading to more of your garden or the neighbor’s. The next step is also equally important : sanitize whatever tool was used to prune the infected area of the plant.
If your plant has a major infestation, Neem oil is an organic remedy that can be sprayed onto the problem areas. Moving forward I’d recommend using the following home remedy for your garden: three uncoated aspirin, one tablespoon of liquid seaweed, and one gallon of water combined to spray leaves and root area at least once a week to prevent recurrence.
Several Florida gardeners have asked what insecticides they should pick up to fix this pest problem. I always highly encourage homeowners to go try several natural or organic options before going the chemical route. Insecticides don’t just kill the bad guys, but they also exterminate beneficial insects, such as ladybugs and wasps. (Yes, I said wasps which I will expand on shortly!) Another important reason not to use insecticides, is it could backfire and make your PHM problem worse.
A few federal and statewide agencies, such as the Florida Department of Agriculture, are using biological efforts to help control the PHM populations. Parasitic wasps are the most common control method that has seen good results. The wasps don’t attack plants and are so small they don’t bother humans.
Overall, it’s best to address garden issues before they get crazy out of control. Once the PHM have infected one or more of your plants, it’s hard to get rid of them but not impossible. A weekly stroll around the yard is never a bad idea to keep an eye on stressed areas and give you more time to troubleshoot.
Sources:
https://edis.ifas.ufl.edu/in156
https://trec.ifas.ufl.edu/mannion/pdfs/PinkHibiscusMealybug.pdf
http://blogs.ifas.ufl.edu/collierco/files/2018/03/Pink-Hibiscus-Mealybug.pdf