With its gorgeous foliage and lush blooms that come in a variety of spectacular shades, hibiscus is certainly a beautiful plant that can accentuate any outdoor space. Unfortunately, homeowners aren’t the only ones that appreciate their value. Several pests find hibiscus irresistible, too, and often announce their presence by eating holes in its leaves.
Aphids, Japanese beetles, caterpillars, earwigs, and grasshoppers are the most common causes of holes in hibiscus leaves. But while they all perforate hibiscus leaves, these pests may manifest in other varying ways, and knowing the signs of each is critical to choosing the right control measure.
If you’ve been noticing unsightly holes in the leaves of your hibiscus plants lately, keep reading to learn more about the above common culprits and the most effective ways to control them.
Aphids on Your Hibiscus Leaves
Aphids are most common during spring and fall and typically live in large colonies. They create tiny holes on hibiscus leaves and flower buds by sucking plant sap from these areas.
They also secrete honeydew, which, more often than not, attracts a swarm of ants that crave these secretions.
Although ants do not damage hibiscus plants per se, you probably don’t want herds of them in your garden. Leafcutter ants, in particular, can kill entire trees.
How to Control Aphids in Your Garden
There are several ways to control aphids in your garden without using chemicals. One such method involves spraying your plants with a steady, pressurized stream of water, such as that from a garden hose.
While water alone won’t kill these bugs, the pressure will knock them off your plants. And because dislodged aphids can’t return to the plant, spraying your plants with pressurized water can be an effective way to keep the bugs at bay. The beauty of this hack is that it doesn’t kill aphids’ natural enemy, ladybug beetles.
In fact, you can combine hose water with a commercial ladybug beetle culture to make your aphids control solution twice as effective. Ladybug beetles feast on adult aphids and their larvae, as well as other slow-moving insects such as chinch bugs, thrips, asparagus beetle larvae, moth eggs, scales, mites, leafhoppers, whiteflies, and mealybugs.
Japanese Beetles Invading Your Hibiscus Plant
Japanese Beetles feed on virtually every part of the hibiscus plant (and over 200 other plant species), from flowers to leaves. These metallic green-gold colored, bee-mimicking beetle species from Asia eat and breeds in broad daylight, so it won’t be hard to spot them.
But identifying Japanese beetles isn’t the problem; that would be controlling them.
Being an invasive species, Japanese Beetles don’t have many natural predators, meaning using biological control methods is off the table. You can’t effectively control them by picking them off your plants, either, because more will appear out of nowhere, not to mention how tiring it can be to pick hundreds of these insects by hand.
How to Get Rid of Japanese Beetles in Your Garden
The most effective way (and just about the only way) to control Japanese Beetles is by using Milky Spore. Milky Spore is a disease that kills them in their early life stages, and you can buy their cultures at your local gardening store.
If it isn’t available locally, but you can check out Gardener’s Supply Company Milky Spore on Amazon. It’s safe for humans and pets, fairly priced, and good for soil-enriching organisms. A 10-oz box will cover 2500 sq.ft (232.2576 sq. meters), so be sure to measure your garden beforehand to estimate how much of it you’ll need.
Caterpillars Feeding On Hibiscus Leaves
For most people, caterpillars are often the first culprit that springs to mind when any garden plant has holes in its leaves, and rightly so. They feed on a multitude of plants, but the hibiscus is particularly prone to three types: the saddleback caterpillar, the Io moth, and the hibiscus sawfly.
The hibiscus sawfly’s larvae typically have yellow-green bodies with dark heads, while the Io moth has a green body with a white/red/purple stripe down the sides. Meanwhile, the saddleback caterpillar has a brown body and green colored back and sides. It also has a brown spot with a white border that makes it look like a saddle.
How to Control Caterpillars in Your Garden
Being able to tell the difference between the signs of earwigs (more on these later) infestation and that of caterpillars is critical to choosing the right control method.
Since both types of worms leave similar-looking bite marks on hibiscus leaves, a surefire way to tell what’s eating your plants would be to look out for “frass.” These are black dots of excrement that caterpillars leave on leaves. Earwigs don’t leave such dots.
If you don’t like to use chemicals in your garden, you can control caterpillars through biological means since many bird species and animals such as lizards feast on them. Birds, in particular, are easy to use as a means to keep caterpillars in check. Simply install bird feeders and houses in your garden to attract birds, and let nature take its course.
Remember that biological control will come with its fair share of drawbacks, most notably birds and other caterpillar predators defecating on structures in your home.
If you prefer the efficiency of chemical control methods, simply spray your garden with Thuricide B.T. This formula works on virtually all types of caterpillars, and is safe to use on all garden plants, including ornamentals (such as hibiscus), vegetables, and fruit trees.
Earwig Infestation Around Your Hibiscus Plant
In most cases, earwigs do more good than harm in gardens because they feed on adult aphids and eggs of other pests. However, that doesn’t mean that they don’t take their fair share of soft plant tissue. When they are a problem, the leaves of your hibiscus plants will look rugged and chewed around the edges.
How to Control an Earwigs Infestation
Earwigs are pretty easy to control, especially if you’re only looking to reduce their numbers (instead of completely eradicating them). Simply fill a pot with hay and leave it for a few days in your garden. It will attract earwigs, after which you can dump them elsewhere.
If you want to get rid of them through deterrence measures completely, sprinkle a good amount of abrasive material such as diatomaceous earth, wood ash, or crushed shells on and around the affected plants. Typically, earwigs avoid abrasive surfaces because they cause small cuts on the insects when they crawl over these materials, which can kill them.
Grasshoppers Habitation in Your Hibiscus Plants
Grasshoppers are often overlooked potential sources of damage to hibiscus and other garden plants, particularly in late summer. If (like most homeowners) your garden is a little wild in September, the chances are that grasshoppers are responsible for the damage you see on your hibiscus plants’ leaves.
That’s because baby grasshoppers mature during this time of the year. This gives them fully-developed wings for hopping from one plant to the next when feeding, as well as a chance to mate and multiply their numbers.
Most grasshopper species feed at night, leaving behind irregular-shaped holes on the leaves. Their life cycle involves incomplete metamorphosis, meaning that baby grasshoppers aren’t that different from adults except for size. When combined, these characteristics make grasshoppers very easy to detect when an infestation occurs.
How to Control Grasshoppers in your Garden
As with many other jumping/ flying insects, you can control using diatomaceous earth.
Alternatively, you can use predators like birds or insects that feed on grasshoppers (robber flies, for instance)by making your garden attractive to these animals.
There are several ways to attract these predators to your garden, but perhaps the most effective one is by introducing something they feed on in your garden.
Lastly, you can use chemical agents to kill grasshoppers. However, that may prove problematic given their mobility, where they lay their eggs, and the multitude of species of these insects.
Final Thoughts
As you can see, holes in hibiscus leaves can be caused by a number of pests, and each has different control measures. Hopefully, you’ll be able to use the solutions we’ve explored to control each pest and keep your hibiscus plants healthy and gorgeous—Best of luck!
ReadyToDIY is the owner of this article. This post was published on August 3, 2020.
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