Bougainvillea diseases and pests

Contents

Green, mean, bougainvillea eating machine

By Ralph E. Mitchell

Did you ever walk by your favorite bougainvillea and notice the tips of the leafy branches chewed to pieces and the culprit apparently gone? I just had that experience the other day. My pink ‘Pixie’ bougainvillea had suffered from some chewing insect which had damaged the tips of each branch and shredded the leaves on down. I poked through the mess and teased out the problem – a small green, pudgy caterpillar which had folded up some leaves and fed inside causing loss of foliage and piles of droppings. What was I dealing with?

As it turned out this caterpillar is known as the bougainvillea leaftier. The caterpillar had actually tied up several leaves with silken threads and formed a foliar tube of sorts offering a safe place to hide from predators. The silken threads actually contract as they dry completing a tight, enclosed shelter. As the caterpillar grows it feeds on the surrounding leaves and excretes droppings that build up within the folded leaf. Before too long, the damage becomes apparent. While the damage may look horrible, it is often more of an eyesore under a normal infestation and will quickly grow back. Damage could be extensive, but, with vigilance, you can normally take control measures before it gets out of hand.

Control measures will include handpicking – which I choose – to suppress the outbreak. I simply examined each branch tip, unrolled the leaf shelter, and dispatched the caterpillar. In this way I became the “predator” and essentially groomed the plant until all offending caterpillars were gone. Interestingly enough, paper wasps were also present hunting for these fat caterpillars to feed their brood – a welcome natural predator. Certain spiders and other beneficial organisms would also take their share of these caterpillars. Earlier on when the leaftier caterpillars were small, I could also have applied Bacillus thuringiensis (Bt) as an insecticide which only kills caterpillars. Another least-toxic material to try is spinosad which is a microbial insecticide derived from a species of soil bacteria. If the infestation is large, you could step it up a bit and try something ”harder” like carbaryl. As with all pesticides, please make sure to read the label, as the label is the law!

Pests like the bougainvillea leaftier will likely pop up from time to time. As such, regular monitoring – which is a part of Integrated Pest Management or IPM – is a common-sense tool that will help you better manage pests in your yard. For more information on all types of pests infesting your landscape, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Don’t forget to visit our other County Plant Clinics in the area. Please check this link for a complete list of site locations, dates and times –

Resources:
Caldwell, D. (2015) Bougainvillea Chewers. The University of Florida Extension Service, IFAS – Collier County.
Porchey, P. (2012) July Gardening Guide. The University of Florida Extension Service, IFAS – Sarasota County.
Buss, E. A. & Park Brown, S. G. (2014) Natural Products for Managing Landscape and Garden Pests in Florida. The University of Florida Extension Service, IFAS.

by spacemonkey

Posted: June 20, 2017

Category: Home Landscapes, Pests & Disease

Tags: bougainvillea leaftier, caterpillars, Integrated Pest Management

What Is Eating My Bougainvillea?

ksbank/iStock/Getty Images

A member of the four-o’clock family, bougainvillea (Bougainvillea spp.) is a vigorous woody vine characterized by scores of papery flowers in shades of magenta, purple, sunset orange and white. It is hardy in U.S. Department of Agriculture plant hardiness zones 9 to 11. Though diminishing the beauty of this lovely plant is tough, some pests do a good job by eating its tender green leaves.

Lousy Loopers

The bougainvillea looper is a species of green or brown caterpillar about 1 inch long that thrives on all species of bougainvilleas, leaving behind heavily scalloped leaf margins. Thoroughly stir 4 teaspoons of Bacillus thuringiensis, a type of soilborne bacteria available at some garden centers, with 1 gallon of water and spray the entire plant evenly using a hose-end or pressurized sprayer. Repeat weekly until pest is under control. Always follow label instructions exactly. Bacillus thuringiensis has a short shelf life and degrades in sunlight, so store it in a cool, dry place inaccessible to pets and children, and use within two years. Avoid contact with skin and clothing. If you inhale or swallow Bacillus thuringiensis, contact the American Association of Poison Control Centers at 1-800-222-1222.

Lose the Leafminers

The larva of various moths and flies are known as leaf miner insects. These insects burrow into leaves, causing winding tunnels and giving leaves a bare, skeletonized look before they drop from the plant. A severe infestation can kill the vine. Bougainvillea Growers International notes that contact pesticides are ineffective, as leaf miners feed inside the leaves. Instead, remove debris from around the base of the plant, as larva and eggs can overwinter there. Keep the planting area well-weeded, and mulch with organic matter to prevent new weeds from emerging.

Slugs and Snails

Slugs and snails nails tend to feed on the middle of leaves, although they sometimes work on the edges as well. Slugs and snails feed in the evening, thriving in damp conditions and leaving behind telltale trails of shining slime. Pick slug and snails off by hand in the evening and drown in soapy water or crush. You can create a physical barrier around your plant by spreading dry chalk, crushed eggshells or sharp cinders around the stem. Oak leaves also work well, since these pests dislike the tannin in the leaves.

Culture and Care

Plants that are stressed due to improper cultural care are more susceptible to attacks from pests. Bougainvilleas do best in bright, sunny situations with rich, loamy and well-draining soil. Water frequently to keep the soil moist, but not water logged or flooded. Watering in the morning will allow the plant to dry out before evening, discouraging slugs and snails. Prune away and destroy any dead, diseased or infested growth with disinfected pruning tools and keep the planting area tidy by removing organic debris.

Identifying and Treating Bougainvillea Diseases

Few bougainvillea diseases are deemed harmful enough to destroy a bougainvillea garden spread. Bougainvillea plants are naturally immune to bacterial diseases and common garden pests. Grown usually for landscaping purposes, bougainvilleas are woody, ornamental shrubs that need minimal care. However, an improper gardening regimen and the failure to spot early signs of fungal infections can cause widespread harm to bougainvilleas.

Bougainvillea Disease 1: Mildew

Powdery mildew is a fungal infection common to most ornamental shrubs. Mildew infections are often caused due to excessive watering of plants and poor soil drainage. Mildew infestations cannot be eradicated for a lifetime. You will have to ensure basic garden hygiene and take some precautions to guard against mildew disease.

Symptoms: The most identifiable feature of mildew infection is the presence of white, powder-like, dusted appearance of the foliage. The infection is more apparent among the leaves than the branches. Crowded branches and dense foliage help in mildew spreading quickly throughout the garden-spread. Root rot is commonly caused by waterlogging in the soil bed but bougainvilleas rarely suffer from it. However, bougainvilleas suffering from mildew infection often develop root rot due to decreased plant vigor.

Treating Mildew: The diseased foliage should be pruned off. You should not use this foliage in the garden compost or for any gardening activity. The best way to reduce chances of a mildew infection is to use a fungicide when transplanting the plants. This also helps to prevent root rot infection. Ensure proper drainage in the soil bed. You can increase the soil’s draining capability by adding some dry mulch prepared from wood bits. During damp weather conditions, regularly check for mildew development. You should water the plant minimally during this period. If signs of fungal growth are present, chemical control can be considered. You can use mild fungicides that contain triadimefon or propiconazole as ingredients. During the growing season, regularly check for decaying foliage and clip it with garden scissors but don’t prune. You should prune bougainvilleas before and after the growing season. Ensure that the basal and mid-level foliage is sufficiently pruned to allow greater air circulation within clustered parts of the foliage.

Bougainvillea Disease 2: Scale Disease

Scale insects or mealybugs are plant parasites, commonly found in household gardens. Mealybugs are attracted to bougainvilleas. They feed intensively on the sap of plants.

Symptoms: The smaller, unhatched scale insects can be observed on the underside of some leaves, covered in a waxy coating. The more mature scales have a sooty, black appearance. Scale infection can be easily detected with extensive canker development on branches and overall, stunted plant growth. Some cankers might develop a bigger, sore-like appearance. Scale-damaged bougainvilleas might have some sap oozing out of these sores.

Treating Scale Disease: You should regularly check for scale insect development. The insect’s eggs are commonly found around the leaf joints. If the number of scale insects is small, you can remove them with a scraping tool. After scarping them off the plant’s surface, wipe the infected site with a cloth dipped in horticultural oil. This seals any underlying canker sores. You can develop a spraying regimen to prevent scale disease. Prepare a mixture of water, insecticidal soap, and horticultural oil. Spray this all over the bougainvillea shrub every two weeks. To control mealybugs, use any of the branded chemical sprays available at garden supply stores. If the scale disease is becoming unmanageable, trying spraying the entire shrub with pyrethrin-based pesticides.

How To Prevent Bougainvillea Looper Caterpillar Damage On Kauai

If 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

Bougainvillea 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, 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

Are you seeing damage on your bougainvillea leaves? Like something’s been chomping and munching away? I’m not talking little nibbles here and there but some serious feasting. I’ll tell and show you what it might be so you can identify the pest and take action.

I had 2 bougainvilleas in my Santa Barbara garden and 4 here in Tucson. I’ve learned a lot about them from working at a nursery but mostly by hands-on experience. They’re relatively easy to maintain except for the pruning which I happen to enjoy (yes, it’s true!) and you can’t beat them for an all-out show of color.

There are a few pests which attack them that I’ve skimmed over in previous bougainvillea posts and videos – so it’s time for more details.

Something eating my bougainvillea leaves! Hopefully, this will help:

3 Possible Pests Are the Culprits

Leaf Cutter Bee

This 1 is very easy to identify because you’ll see large even chomps, like half moons, taken out of the sides of the foliage. You rarely see the leaf cutter bee itself because it does its thing & then is gone. I never saw leaf cutter bees in Santa Barbara but I did have them on 1 of my bougies in the spring. Nothing too bad but enough for me to notice. It’s now the very end of August & low & behold, I found 1 leaf with the evidence so I could show you.

What you should do as treatment: Nothing. These bees are beneficial pollinators & we need them. The leaves will grow back & by the way, they can’t be bothered with us humans so you don’t have to worry about being stung.

Evidence of leaf cutter bees. My how neatly they eat!

The next 2 pests are caterpillars which mean they eat like crazy. There are so many different types of caterpillars & they’re all hungry critters. The damage done by caterpillars can vary a bit but the treatment is generally the same.

All caterpillars (not only this one) eat & poop like crazy so the little black specks you’ll see on the leaves is their frass. And yes, caterpillar excrement has it’s own word.

Head’s up: Those black droppings are a sign caterpillars are in the house!

These are the 2 which I have seen on my bougainvilleas & have experience with:

Leaftier Caterpillar

I didn’t see these on my bougies in Santa Barbara either. They protect by getting on the under the leaves, rolling themselves up & then closing the leaves with silk threads. After the caterpillars have gone, you can unroll a leaf & still see evidence of the threads on the undersides. The damage to the plant is mainly at the end of the stems, as far as I can see anyway.

The leaftier caterpillar. You can see the webbing, like threads of silk, on the leaf behind the caterpillar which I unrolled.

Here’s the damage done to the ends of the stems by the leaftier. You can see how 1 of the leaves is rolled up.

Bougainvillea Looper

These are the most common chewing pests which attack bougainvilleas that I know of. My Bougainvillea glabra had them big time in Santa Barbara every year come late July. They’re inch worms & can be brown to green to yellow. The loopers are hard to spot because they hang out under the leaves & do their feeding at night.

To me, they damage they do a lot more damage then the leaftier. The leaves get chewed extensively, both old & new, & can ultimately look like thin lace or be gone all together. I’ve never seen the looper cause leaf curl – please let us know otherwise if you have.

Here’s what the bougainvillea looper looks like; basically a small green inchworm. In the video, you can see the damage done to my mint by the cabbage looper. It looks similar to the damage this looper does.

Treatment For These Caterpillars on Your Bougainvillea Leaves

Head’s up: These pests don’t do any harm to or endanger the health of an established plant. All the damage is cosmetic. Bougainvilleas shed & regrow foliage a couple of times a year so you’ll see new leaves appear. On the other hand, a young plant could be susceptible to a bad infestation.

Here are your three options for treating these bougainvillea pests:

1.) Nothing

My bougainvilleas are well established & the damage doesn’t bother me, with either caterpillar. They hatch into moths, fly away & then I won’t see them again for a year. That being said, I will eventually prune off the damage done by the leaftiers. I would let the loopers be because my glabra was so full & dense it was hard to see unless I got close up.Remove them by hand.

2.) Remove the Pests by Hand

This is much easier to do with the leaftier as you can find them covered in silk inside the rolled up leaves during the day. The looper is much harder to find so this would be extremely labor intensive.

If you choose to control them with a spray, my word of advise would be to do it early on before the infestation gets worse. Reapply if the caterpillars return. Be sure to spray where the caterpillars to make it effective. Even though both of these sprays are reported to be non-harmful to beneficial insects, please be sure to spray around dusk when they aren’t as active.

3.) Spray the Leaves

BT is a naturally occurring bacteria which makes the caterpillars sick & ultimately causes them to die. It’s considered to be a natural pesticide. When I worked at a nursery, this is what we always recommended to control caterpillars. The other product would be neem oil. It’s reported to control caterpillars though I have no experience with this. Please let us know if you have.

Head’s up: caterpillars are treated differently so insecticidal soap & horticultural oil wouldn’t be effective at all – don’t waste your time.

I’ve noticed that these pests don’t seem to attack the flowers and that’s a very good thing. We want that explosion of color that only bougainvillea leaves can provide! By the way, none of my other plants have been attacked by these pests. Whether you choose to treat or not, do a little more research to see what’s best for you, the plant and the environment.

Happy gardening,

what is causing the faded flowers and curling leaves?

You dont say how long you have had your plants or if these are new to you/garden, These plants are from Brazil, therefore they will be used to fairly constant temp’s however, they do have a growing/flowering season, so perhaps as Jasperdale has said, they have started to fade due to the cooler temps you have had over the past few nights, I can only say that as with all flowers, some colours fade faster than others, as for the leaves curling, it could also be a cooler temp, I was not too sure if I noticed some white-fly on one of the leaves right in the center of the pic, it may just have been drops of moisture, but worth a check, however, they are usually trouble free but we have all experienced some strange diseases and bugs that we dont usually have especially this year, I think most gardeners have had there ups and downs this year. Back to your plants, if they are going into a slight winter dormancy, then give less water than summer time, best way to find out if your plant needs water, is to poke your finger into the soil to about 2 or 3 inches, you will soon feel if the soil on these 2 plants are short of water, if you have a soak watering system, maybe some of the nozzles are blocked up, if it is overhead spraying, look see if the water spray has been altered by the mower/birds digging etc, it is worth checking out all the obvious things just to put your mind at rest, hope you get this solved as they are wonderful plants and unfortunately, I can only grow mine indoors and in pots, while growing, I have to give mine a feed every week in summer as they do use a lot of energy flowering for long periods. so good luck. WeeNel.

Common Diseases & Problems

A part of the bougainvillea’s appeal is that they are relatively disease and pest-free plants. It is NOT common for your bougainvillea to be affected by these pests and diseases if you follow BGI’s Rules for Care, and fertilize with Bougain® which contain a significant amount of micronutrients – vital for healthy, blooming bougainvillea. This page contains most (but not all) common pests/diseases that may affect your bougainvillea.

On the rare occurrences that your bougainvillea experiences pest problems or disease, always try the least toxic method of pest control as your first step. If you use chemical pesticides to control insect pests, you will also kill natural predators. If you choose a chemical control, follow directions and guidelines closely and always wear protective clothing and safety gear including a long-sleeved shirt, long pants, neoprene gloves, goggles and a respirator. Chemical pesticides are not recommended for use inside the home.

Aphids

Known also as greenfly, blackfly or plant lice, aphids are minute plant-feeding insects. Important natural enemies include the predatory ladybugs/ladybirds/ladybeetles, and lacewings. Aphids are tiny, pear-shaped, sap-sucking pests, appearing in the spring to feast on your plants’ tender new leaves. They leave behind a secretion that attracts ants and promotes mold growth. Not to fear; you don’t have to resort to toxic chemicals to save your bougainvillea.

Natural Control

  1. Examine your garden regularly for signs of aphids. Look for clusters of the little bugs on new growth as well as on the curled and twisted leaves.
  2. While wearing gloves, remove the aphids by hand, or use a sharp stream of water to knock them off the plant.
  3. Cut away and dispose of infested foliage.
  4. Capture flying aphids by placing yellow sticky traps near infected plants.
  5. Make a nontoxic pesticide by mixing 1 cup vegetable oil with 1 tablespoon liquid dish-washing soap. Add 1½ teaspoon solution per cup of warm water to a handheld spray bottle.
  6. Hit the aphids directly with above mixture and spray entire plant thoroughly.
  7. Introduce beneficial insects, such as ladybugs/ladybirds/ladybeetles, or green lacewings to your garden to feed on the aphids. Both can be bought from garden stores or online.
  8. Avoid planting bougainvillea near aphid-attracting plants, such as birch trees, and instead grow plants such as white sweet clover, spearmint, sweet fennel and Queen Anne’s lace, which attract and house the lacewings, ladybugs and other insects that feed on aphids.
  9. Rid your garden of ants. Ants love to eat the sugary sap (honeydew) secreted by aphids, and will “farm” the aphids, protecting them on the plant they eat.

Caterpillars; namely the Bougainvillea Looper Caterpillar

The bougainvillea looper is a green or brown caterpillar about 1 inch long. It is also called inchworm or measuring worm. The looper larva mimics stems and branches very well and feeds primarily at night, which is why you may see the damage but fail to find the culprit on the plant. The adult is a moth, a very fast flyer with a wingspan of about 1 inch. The moth does not feed on the foliage. Like the larva, it also is active at night, when it is believed to lay its eggs on the underside of bougainvillea leaves. Go out scouting very early in the morning or at night if you have a good strong flashlight. The bougainvillea looper feeds from the edges of the leaves, which results in severe scalloping of the foliage. Attacks begin on the young tender shoots and leaves before progressing down the stem. The insect will cause significant visual damage to bougainvillea, although this does not apparently result in the death of the plants.

Chemical Control

Bacillus thuringiensis (BT, or Dipel®) and neem-based biological insecticide products should are a good solution and should be effective on the loopers without harming other insects that may biologically control them. Insectical oils and soaps will not control caterpillars such as the looper. Most synthetic insecticides with labels permitting use against caterpillars on landscape ornamentals, such as carbaryl (Sevin®), will likely kill the bougainvillea looper, although these products are often destructive to beneficial insects as well. Spraying insecticides late in the evening is recommended. This is when the bougainvillea looper caterpillars and adult moths are active, and also when the beneficial insects are not likely to be active.

Leafminers: Moths, Flies, Beetles, Wasps

The vast majority of leaf-mining insects are moths (Lepidoptera) and flies (Diptera), though some beetles and wasps also exhibit this behavior. Although the types of insects differ, the damage they cause is very similar. Because of this, the larval stages of all insects which leaf mine are collectively and generically called “leaf miners”. All leaf miners will cause the leaves to look skeletonized, and to fall from the plant. Eventually they can kill the plant.

Natural Control

Cleaning around the plant is your best solution. Like wood borers, leaf miners are difficult to control as they are protected from insecticide sprays and plant defenses by feeding within the tissues of the leaves themselves. Some leaf miners can be killed by systemic pesticides (a type of pesticide that moves inside a plant following absorption by the plant), but many breeds are still immune to the effects of pesticide.

  1. Cleaning around the plants. Debris tends to collect at the base of plants, and this is where the adults of the leaf miner larvae lay their eggs. Some leaf mining larva may also “winter over” in this debris. Removing leaves and other debris from around plants is an excellent method for controlling them.
  2. Weeding provides an alternate food source for leaf miners, so areas around plants should be weeded and mulched.
  3. Do not use contact pesticides. Since the leaf miner is inside the leaf, contact poisons cannot reach it, and therefore cannot kill it. Additionally, leaf mining insect larvae quickly become resistant to contact pesticides.

Scale Insects: Parasites, Mealybugs

Most scale insects are parasites of plants, feeding on sap drawn directly from the plant’s vascular system. Scale insects vary dramatically in their appearance from very small organisms (1-2 mm) that occur under wax covers (some look like oyster shells), to shiny pearl-like objects (about 5 mm), to creatures covered with mealy wax. Scale insects’ waxy covering makes them quite resistant to pesticides, which are only effective against the juvenile crawler stage. Over time, scales and mealybugs turn leaves black with “sooty mold”.

Natural Control

  1. Identify scale insects by looking on the undersides of leaves and around leaf joints. Scale-damaged plants look withered and sickly and may have sticky sap or a black fungus on the leaves and stems.
  2. Move an infested plant to isolate it from the rest of your collection. Scale insects are invasive and will infest other plants.
  3. Remove scale insects with a twig or scraping tool. They will scrape off of plant tissue easily.
  4. Wash infested plants with a soap/oil mixture if scraping alone doesn’t do the job. Mix ½ tsp. insecticidal soap, ¼ tsp. horticultural oil into 1 quart of warm water. Wash the leaves individually with the soap/oil mixture. Rinse well. There are also numerous chemical products available for the control of mealybugs.
  5. Purchase and release a natural predator called Chilocorus nigritus or Lindorus lophanthae for serious infestations. Place the insects directly on the infested plant. Once they have consumed the scale, the predators will simply die from lack of food in the indoor environment.
  6. Spray with pyrethrin as a last resort. Pyrethrin is an organic pesticide made from chrysanthemums.
  7. Be diligent – examine infested plants for evidence of new scale every day. It may take some time, but your bougainvillea will thank you!

Snails & Slugs

Photo Credit: Weidners’ Gardens. Encinitas, California, Jeffrey Lotz; FDACS-DPI and David Robinson.

Snails usually eat from the middle of the leaf, but they can take bites out the edges as well. All this biting and chomping will make the leaf look scalloped. Putting down barriers that slugs can’t cross is, perhaps, the best way to protect your garden from these common pests. Keep them from entering and you won’t have to use pesticides.

Natural Control

  1. Water your garden only in the early morning, or use an underground irrigation pipe. This will keep the top of the soil dry and uninviting to slugs and snails.
  2. Spread dry soot, dry ashes, dry lime, sharp cinders and dry chalk around plants or beds. Any one of these or several in combination should do the trick.
  3. Rough, sharp sand is another option. Use it the same way as the materials in Step 2.
  4. Try calcified seaweed or crushed eggshells as a barrier.
  5. Another barrier material is clippings from thorny roses or holly leaves. Rosa rugosa (Japanese rose) clippings are good.
  6. Spread pine needles in your garden (these are also good mulch for strawberries).
  7. Spread chopped hair (human hair is fine) in your garden.
  8. Try using oak leaves as a barrier. Slugs and snails don’t like the tannin in the leaves.

Chemical Control
Any brand of slug/snail killer will do the job. Sluggo is good because it can be used around pets and people.

Mites; namely Spider Mites

The webspinning two-spotted spider mite occasionally makes their home on bougainvillea. To the naked eye, spider mites look like tiny moving dots. Adult females, the largest forms, are less than 1/20 inch long. Spider mites live in colonies, mostly on the under-surfaces of leaves. The names “spider mite” and “webspinning mite” come from the silk webbing most species produce on infested leaves. The presence of webbing is an easy way to distinguish them from all other types of mites. Mites cause damage by sucking cell contents from leaves. A small number of mites is not usually reason for concern, but very high populations—levels high enough to show visible damage to leaves—can be damaging to plants. At first, the damage shows up as a stippling of light dots on the leaves; sometimes the leaves take on a bronze color. As feeding continues, the leaves turn yellow and drop off. Often leaves, twigs, and fruit are covered with large amounts of webbing. Damage is usually worse when compounded by water stress. Check the undersides of leaves for mites, their eggs, and webbing; you will need a hand lens to identify them. To observe them more closely, shake a few off the leaf surface onto a white sheet of paper. Once disturbed, they will move around rapidly. Be sure mites are present before you treat. Sometimes the mites will be gone by the time you notice the damage; plants will often recover after mites have left.

Natural Control
If a treatment for mites is necessary, use selective materials, preferably insecticidal soap or insecticidal oil. Petroleum-based horticultural oils or neem oils are both acceptable. Oils and soaps must contact mites to kill them so excellent coverage, especially on the undersides of leaves, is essential and repeat applications may be required. Mid-season washing with water to remove dust may help prevent serious late-season mite infestations. Regular, forceful spraying of plants with water will often reduce spider mite numbers adequately. Be sure to get good coverage, especially on the undersides of leaves.

Chemical Contol
Spider mites frequently become a problem after the application of insecticides. Such outbreaks are commonly a result of the insecticide killing off the natural enemies of the mites, but also occur when certain insecticides stimulate mite reproduction. Naturally controlling mites is the best method.

Thrips

Thrips are tiny, slender insects with fringed wings that cause discoloration and deformities on bougainvillea and other plants. Other common names for thrips include thunderflies, thunderbugs, storm flies and corn lice. Thrips are generally tiny (1 mm long or less) and are not good flyers, although they can be carried long distances by the wind. Thrips feed by piercing plant cells with their paired maxillary stylets, which form a feeding tube. Due to their small size, cryptophilic behavior, and high rate of reproduction, thrips are difficult to control using classical biological control. Only two families of parasitoid hymenoptera are known to hunt them, the Eulophidae and the Trichogrammatidae.

Whitefly

Whiteflies typically feed on the underside of plant leaves. Whiteflies feed by tapping into the phloem of plants, exposing plants to the whiteflies’ toxic saliva and decreasing the plant’s overall turgor pressure. The damage is quickly elevated as whiteflies congregate in large numbers, quickly overwhelming susceptible plants. Damage is further exacerbated as whiteflies, like aphids, excrete honeydew as a waste product, which promotes mold growth. Whitefly control is difficult and complex, as they rapidly gain resistance to chemical pesticides. A major problem is the fact that the whiteflies and the viruses they carry can infect many different host plants. Use of yellow sticky traps to monitor infestations and only selective use of insecticides is advised.

Fungal and Bacterial Leaf Spot (Pseudomonas and ropogonis)

The early symptoms are small reddish-brown leaf spots which usually occur on younger foliage, and cause the leaves to look “rusty”. These enlarge into circular or irregular dark necrotic spots. When environmental conditions are drier and less favorable, leaf spots are slower to develop. Lesions have a tan center surrounded by a dark redbrown margin, and are sometimes bordered by a chlorotic halo. In time, leaf edges may become ragged as the necrotic tissue turns dry and papery. Under conditions of high rainfall or relative humidity the lesions develop quickly and are often black and vein delimited.
Infection of developing leaves and bracts results in puckered, distorted growth.

Defoliation will occur when leaf spotting, blighting or marginal necrosis becomes severe.

Natural Control
Maintaining dry foliage is the primary control measure. Prune branches back and away from each other or, if just starting to grow, allow a large amount of space between them. Branches that are overlapping can’t dry quickly and become more susceptible to leaf spot disease. Remove infected leaves and/or plants from the growing area.
Dispose of them immediately to reduce the spreading of infection.

Chemical Control
Spray fungicide in the spring if necessary. It will not cure infection that is already there, but it can control the spread of it. In frost-free climates where bougainvillea is perennial, disease incidence drops during cool and/or dry weather.

Black, Sooty Mold

See “Aphids”, “Scale Insects: Parasites, Mealybugs”, and “Whiteflies”

Leaf drop

Problem as a result of over-watering, under-watering, low light levels, or cold temperatures.

Leaf spots

Yellow or tan spots appear on older leaves may be sign of Magnesium deficiency (common with yellow bougainvillea varieties), or from over-watering.

Root rot

Plants that are over-watered or subjected to water logged conditions can develop root or stem rot. It’s easily prevented by careful handling and by the application of a broad spectrum fungicide drench during transplanting or planting in the landscape.

Scalloped Leaves a.k.a. “Help, Something’s Eating My Bougainvillea!”

See “Snails & Slugs” and “Bougainvillea Looper Caterpillar”

Yellowing or chlorosis on new growth

Often a result of a magnesium or iron deficiency, and an application of a complete micronutrient blend should help, but use caution–too much of either Mn or Fe will result in a secondary deficiency, as the plant is unable to absorb one when the other is present at high levels.

Yellowing or chlorosis on old growth

Often a result of a magnesium or iron deficiency. Apply Epsom salts at 1-2 tsp/gal as a drench or foliar spray.

Deficiency signs

Nitrogen deficiency: Older leaves turn a pale green and the veins are usually a reddish color. New growth will be stunted.

Phosphorus deficiency: The veins will turn red to purple and the plant as a whole will look purplish.

Potassium deficiency: Causes the edges of older the leaves to be a purple color and the leaf tips will be a brownish color.

Magnesium deficiency: First appears on older leaves where they turn a spotted yellow or tan color.

Zinc deficiency (rare): Will look almost like magnesium but here the leaf will be twisted.

Iron deficiency: Young growth is stunted and pale — you’ll know its iron if the veins on the leaf remain green.

Calcium deficiency: Dead areas appear in young growth and the tips soon die.

Bougainvillea Plant Pests: Learn More About Bougainvillea Loopers

Few plants better represent warm weather climates than the bougainvillea, with its bright bracts and lush growth. Many bougainvillea owners may find themselves at a loss when suddenly their healthy bougainvillea vine looks as though a mysterious night-time intruder has eaten away at all the leaves.

This damage is caused by bougainvillea loopers. While not deadly to the plant, their damage is unsightly. Learn how to control the bougainvillea looper caterpillar below.

What Does a Bougainvillea Looper Caterpillar Look Like?

Bougainvillea loopers are small worm-like caterpillars that are commonly called “inchworms.” They will move by bunching up their body and then stretching back out, as though they are measuring the space.

The bougainvillea looper caterpillar will be yellow, green or brown and will be found on bougainvilleas, but may also be found on plants from the same family as the bougainvillea, such as four o’clocks and amaranthus.

These bougainvillea worms are the larva of the somber carpet moth. This moth is small, only about 1 inch wide, and has brown wings.

Signs of Bougainvillea Caterpillar Damage

Normally, you will not know you have bougainvillea loopers until you see their damage. These bougainvillea plant pests are very hard to spot, as they tend to blend into the plant and will feed only at night, while hiding deep in the plant during the day.

The signs that you have bougainvillea looper caterpillar is mainly damage to the leaves. The edges of the bougainvillea leaves will look chewed on and have a scalloped edge. A heavy infestation may even result in tender shoots being eaten and even complete defoliation of the affected bougainvillea vine.

While the damage may look terrible, bougainvillea caterpillar damage will not kill a mature, healthy bougainvillea vine. It may be a threat to a very young bougainvillea plant though.

How to Control Bougainvillea Looper Caterpillars

Bougainvillea loopers have many natural predators, such as birds and omnivorous animals. Attracting these animals to your yard can help keep the bougainvillea looper caterpillar population under control.

Even with natural predators, bougainvillea loopers can sometimes multiply faster than the predators can eat. In these cases, you may want to spray the plant with a pesticide. Neem oil and bacillus thuringiensis (Bt) are effective against these bougainvillea plant pests. Not all pesticides will have an effect on bougainvillea loopers, though. Check the packaging of your chosen pesticide to see if it affects caterpillars. If it does not, then it will not be useful against the bougainvillea looper caterpillar.

How to Manage Pests

Bougainvillea looper— Disclisioprocta stellata

The bougainvillea looper is a smooth-skinned yellowish or green to brown caterpillar, up to 1 inch long. Like other loopers, or “inchworms”, these caterpillars move by drawing their rear up to their head in a loop, then moving their front legs forward. Adults are fast-flying gray to brown colored moths with a wingspan of about 1 inch. Larvae and adults are active at night.

Damage

Newly hatched and young larvae feed on tender shoots and along the edges of leaves, causing them to appear scalloped. Older larvae feed on mature leaves. Heavy infestations may cause severe defoliation. Adults do not feed on foliage.

Solutions

Check bougainvillea periodically during warm weather for signs of a looper infestation. Look for feeding damage and dark fecal pellets. Birds and other natural enemies feed on loopers, but may not provide adequate control at certain times of the year. Applications of Bacillus thuringiensis will control young loopers, but may not be very effective against mature ones. Spinosad is effective against both mature and young larvae.

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