How To Prevent Bougainvillea Looper Caterpillar Damage On Kauai

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scalloped leaves on bougainvillea plants bougainvillea looper caterpillarIf you spot scalloped leaves on your bougainvillea plants—foliage that looks daintily munched on—then the culprit is a small but mighty hungry caterpillar known as the bougainvillea looper. The green or brown caterpillar is an inch long (earning it the nickname “inchworm”) and blends in with bougainvillea branches and stems, making it a tough pest to spot.

It doesn’t help that this looper likes to feed at night, so you won’t catch it feeding on leaves when landscape crews are generally on your property maintaining or treating plants. It’s like waking up in the morning and finding out that a hungry caterpillar had a midnight snack—your plants!

Bougainvillea looper caterpillars were first reported on Oahu in 1993, and since have spread to Maui, the Big Island, Kauai and likely Molokai. If you’re a commercial property owner in Kauai, you should know how to identify the looper, what its damage looks like and how to control it before their appetites take over and you’re left with naked (as in, no foliage) bougainvillea.

Protect the bougainvilleas on your Kauai commercial property. Here’s what you need to know to prevent bougainvillea looper caterpillar damage.

Be Aware—If Your Landscape Includes Bougainvillea

Bougainvillea is a popular Kauai landscape plant because of its bright bracts, lush leaves and preference for warm climates. That’s why so many commercial properties on Kauai are landscaped with some bougainvillea —it’s colorful, full and eye-catching. But if you own some bougainvillea, then you should know that the bougainvillea looper caterpillar is a pest risk and you must constantly monitor your plants. (More on that below.)

The bougainvillea looper is usually found feeding on purple bougainvillea, but it does not discriminate and will settle in on any variety. These loopers are also known to feed on plants in the Nyctaginaceae family like the four-o’clock (Mirabilis jalapa).

So, if your Kauai landscape includes bougainvillea of any variety or four-o’clocks, understand that these plants are a target for damage by this “inchworm.”

Identify The Pest Before It Latches On

prevent bougainvillea looper caterpillar damage with the right insecticideBougainvillea looper caterpillars are born from fast-flying winged moths (the adult) that are also about one inch in size and harmless. They fly around at night, land on bougainvillea foliage and lay eggs on the undersides of leaves.

If you notice moths hovering around your bougainvillea plants at night, you can bet that you’ll have looper presence before long. The larvae are hard to spot because they blend in with the stems and branches of plants, and they feed at night.

At this early stage, you can treat your bougainvillea—before caterpillar larvae hatch, grow and feed on your plants. A professional landscaper can advise on the best insecticide that will protect the plant without harming beneficial insects.

Identify Symptoms Before Damage Progresses

The problem with these looper caterpillars is that you generally will not know they’re present until they cause enough visible damage on the plant to trigger an “aha!”—something is wrong here. And by this time, your bougainvillea might already be under distress. They feed on the edges of leaves, nipping away at foliage and giving it a scalloped appearance.

The thing about looper caterpillars is, they don’t actually hurt the plant’s health, but they do make for an unsightly bougainvillea. And they can completely defoliate the plant if you don’t control the pest. Even a severely infested bougainvillea that loses its leaves will live on. But, as a commercial property owner, you’ll likely make the decision at this stage to replace the plant for aesthetic reasons, which is an additional cost to you.

Select An Insecticide That Protects Beneficial Insects

There are a number of products you can use to control the bougainvillea looper caterpillar

There are a number of products you can use to control the bougainvillea looper caterpillar, but take care to choose an insecticide that will not take out good insects that can actually control the loopers. Parasitic, mud and paper wasps do a good job of biologically managing loopers.

Of course, if you’ve got an infestation on a plant, you’ll need an insecticide. Bacillus thuringiensis (known as BT or Dipel®) and neem-based biological insecticide products will stop loopers without harming beneficial insects. This is sprayed on the leaves. Spinosad is applied to the soil at the base of the plant, which soaks in the insecticide. Loopers that feed on leaves digest the spinosad and die on contact.

While many insecticides are labeled to use against caterpillars in the landscape, products containing carbaryl will likely take out beneficial insects in the process.

Constant Monitoring Protects Bougainvillea—and All Plants

Understanding what pests can be present on your Kauai commercial property, knowing how to identify them, and monitoring the landscape for infestations will go a long way toward protecting plants.

But we get it—as a commercial property owner—you can’t do it all. That’s why enlisting in a landscape professional that understands Kauai’s unique growing environment is a wise move. You’ll catch pests before they become a problem, and you’ll protect the investment in your landscape while avoiding costly plant replacement from insect damage.

Let’s talk more about how to keep your plants, including bougainvillea, healthy and beautiful. Call us any time at 808.335.5887, or fill out this simple contact form and we’ll get in touch with you.


Images: Damaged leaves, Looper caterpillar, Damaged leaf


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