Hidden Valley Hibiscus
Growers & Hybridizers of Exotic, Tropical Hibiscus
Hibiscus Gall Midge
All I get is Tiny Yellow Buds and No Flowers! Why?
Microbud Infested with Gall Midge
Yellow, Skinny, Drooping
Hibiscus gall midge is not all over the United States yet. It is thought to be native to southeast Asia, and has been in Hawaii since the early 1900's where it is called "blossom midge." It was carried in plants to Florida in the mid-1990's, and since then has slowly moved along the Gulf Coast area, through Louisiana and into southeast Texas. If you live outside these areas, you will most likely be safe from hibiscus gall midge. But if you have bought plants from the Gulf Coast states, you could have imported this frustrating pest without realizing it.
Hibiscus gall midge are very similar to thrips. Like thrips, adult insects fly onto the bud to lay their eggs. The eggs hatch, and the larvae (little yellow worms) eat their way through the buds, destroying them as they munch, until they drop with the fallen bud into the soil beneath the plant. The larvae then burrow into the soil to pupate for about 3 weeks. When they emerge from the soil as adult insects, they fly away, then go find a new bud to lay their eggs in.
How Can I Tell if I have Hibiscus Gall Midge?
The first sign that your hibiscus have thrips and gall midge both is that the buds drop off before the flower opens. To tell the difference between these two pests, look at the fallen buds closely. Thrips allow the buds to get fairly big before they infest them. When thrips damage a bud, the petals are already visibly forming ("showing color") but the bud turns a rotten, grayish-brown color, then it falls off or stays on the bush and fails to open into a flower. Thrips larvae are so tiny that when you break open a bud, you can barely see them. If you do see them, they look like tiny black lines, like this typed hyphen: -
A Healthy Microbud ~
Plump, Green, Upright
How do I get Rid of Hibiscus Gall Midge?
Treating hibiscus gall midge takes some work. These resilient bugs can be quite hard to get rid of. It's important to carefully treat each stage of the midge's lifecycle.
Gather the Yellow Buds Every Day:
First and foremost, gather up all the yellow buds you find every day. It is best to pick them off the plants before they fall, but if any fall it is still a good idea to gather them up. Seal them into a zip lock bag and dispose of them in the trash right away. The idea is to break their life cycle by preventing the larvae from emerging from the bud and burrowing into the soil to pupate.
Drench Pesticide into the Soil:
Use a systemic pesticide in the soil around the base of your hibiscus plants to kill any larvae that have burrowed into the soil. Bayer Tree and Shrub is a good systemic pest control products that will kill the midge in soil.
Sprays the Buds and Tops of your Hibiscus:
As a final precaution, to kill any adult flying bugs and crawling larvae on your plants, spray all buds, branch tips, and tops of your hibiscus with Bayer Advanced 3-in-1 or a similar insecticide that kills insects actively feeding on plants.
There is a lot of work involved with getting rid of hibiscus gall midge, but you'll be glad you did it when you see your hibiscus start blooming again. Remember, the best prevention for both thrips and gall midge is to clean up spent blooms and fallen buds as often as you can. Daily is best of course, but if you can't manage it every day, try to clean them up once or twice a week at least.
Here's to happy, bug-free blooming!