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.
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.
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.
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.
Yellow or tan spots appear on older leaves may be sign of Magnesium deficiency (common with yellow bougainvillea varieties), or from over-watering.
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.
With their vibrant pinkish-red bracts and lush foliage, Barbara Karst bougainvilleas make stunning additions to tropical gardens. However, these plants can fall prey to borers, which are destructive pests that tunnel into stems and branches. borers are the larvae of certain moths and beetles that feed on the inner bark and tissues of plants, eventually killing them if left uncontrolled. Getting rid of borers on your prized Barbara Karst bougainvillea requires persistence and an integrated pest management approach. This comprehensive guide covers borer identification, prevention, and effective control strategies to eliminate infestations.
Identifying Borer Infestations
The first step is learning how to spot the signs of borer activity
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Small holes in stems and branches, These are entry/exit holes created by borers
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Sawdust-like frass around base of plant or on leaves This results from borers chewing through plant tissues
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Wilting, yellowing leaves or dying branches. Borers disrupt water and nutrient flow.
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Swollen or cracked stems. Chewing damage compromises structural integrity.
Carefully inspect plants frequently to detect borer infestations early before extensive damage occurs. Act quickly at first signs.
Preventing Borer Infestations
Prevention is key to avoid borer issues:
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Select borer-resistant bougainvillea varieties when available.
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Maintain optimal growing conditions. Healthy, vigorous plants better withstand pests.
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Prune out dead/damaged branches which attract borers.
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Control weeds around plants to eliminate alternative borer hosts.
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Use pheromone traps to monitor and disrupt borer mating cycles.
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Apply preventive trunk spray of neem oil to deter borers.
Non-Chemical Borer Treatments
Several effective options control borers without harsh pesticides:
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Handpick and destroy borers and eggs when noticed. Check undersides of leaves.
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Introduce natural predators like birds, parasitic wasps, or green lacewings to eat borers.
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Use sharp knife or wire to slice out borer tunnels within stems.
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Inject boric acid or nematodes into borer holes to kill larvae inside.
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Apply neem oil spray as a repellent and feeding deterrent.
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Insert straws coated in Tanglefoot paste into holes to trap emerging borers.
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Hang pheromone or blacklight traps around plants to capture adult moths.
Organic Borer Treatments
When natural remedies fail, try these organic-approved borer treatments:
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Bacillus thuringiensis (Bt) – This bacteria-based insecticide is effective against borer larvae.
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Spinosad – Made from a soil microbe, spinosad works systemically against borers.
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Pyrethrins – Derived from chrysanthemums, these compounds kill borers on contact.
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Azadirachtin – Neem-based azadirachtin repels and disrupts borer growth.
Always follow label directions for these organic pesticides to safely and effectively control borers. Multiple applications are likely needed to break borer life cycles. Rotate between different options to prevent resistance.
Conventional Insecticide Options
For severe borer infestations, conventional insecticides may offer stronger knockdown:
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Imidacloprid – Absorbed by plants, imidacloprid poisons borers ingesting tissues.
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Carbaryl – This carbamate insecticide kills borers on contact.
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Lambda-cyhalothrin – A pyrethroid that provides rapid borer knockdown.
While very effective, these chemicals may negatively impact beneficial insects. Use judiciously according to label instructions and local regulations.
Borer Treatment Program
The best borer control integrates multiple tactics into a treatment program:
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Monitor plants routinely for early detection.
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Remove and destroy severely damaged branches.
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Apply preventive neem oil spray to deter infestation.
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Introduce natural predators to provide biological control.
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Inject borer tunnels with nematodes or boric acid solution.
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Spray spinosad or Bt weekly to kill larvae.
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Hang pheromone traps around perimeter to disrupt mating.
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Rotate between different organic pesticides to prevent resistance.
Remain vigilant with follow-up monitoring and maintenance applications to achieve complete borer elimination. Avoiding chemical pesticides whenever possible reduces risks for bees, butterflies and other beneficial insects in the landscape. Implement preventive practices going forward to protect your Barbara Karst bougainvilleas from future borer issues.
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.
- 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.
- Weeding provides an alternate food source for leaf miners, so areas around plants should be weeded and mulched.
- 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.
How to Grow Beautiful Barbara Karst Bougainvillea – Tips and Tricks for Success
How much water does Barbara karst bougainvillea need?
Barbara Karst Bougainvillea needs 0.8 cups of water every 9 days when it doesn’t get direct sunlight and is potted in a 5.0″ pot. Use our water calculator to personalize watering recommendations to your environment or download Greg for more advanced recommendations for all of your plants. Does your plant get direct sunlight?
When to plant Barbara karst bougainvillea?
Choosing the Right Time and Location: The best time to plant your Barbara Karst Bougainvillea is in spring or early summer after the danger of frost has passed. Select a location that receives full sun, ideally at least 6-8 hours of direct sunlight daily. Bougainvillea thrives in warm temperatures. Ensure the planting site has well-draining soil.
How do you care for Barbara karst bougainvillea?
Barbara Karst Bougainvillea is a fast growing plant and may deplete the nutrients in its soil over time. Replenish them with a gentle organic fertilizer or compost every 1-2 months depending on your location and season. Fertilize more often during the growing season and in warmer and brighter climates.
Why does my Barbara karst bougainvillea lose its leaves?
There are times when my Barbara Karst Bougainvillea loses its leaves, particularly if it gets too cold. It’s a semi-deciduous plant, which means it can shed its leaves in response to stress, like a drop in temperature or insufficient water. However, once the conditions improve, it usually bounces back with new growth.