Control of Spider Mites

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The twospotted spider mite, a natural enemy of the bougainvillea. Image by unh.edu

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. Check the undersides of leaves for mites, their eggs, and webbing; you will need a hand lens to identify them.

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.

Natural Control
Cleaning around the plant is your best solution. Debris tends to collect at the base of plants, and this is where the adults lay their eggs. Some 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 pests, so areas around plants should be weeded and mulched.

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Factors to Consider when Caring for Bougainvillea

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Pruning and pinching is an important technique for bougainvillea growth. Image by bgi-usa.com

Environment

1. Light

Bougainvillea prefer full sunlight and like to be kept outside in the sun or indoors where an adequate amount of sunlight available. Some harsher areas, such as desert-like environments, can be a bit tough on the plant, so make sure to be careful. If the plant does not receive enough sunlight, it will grow without any leaves.

2. Water

Water drainage is essential for bougainvillea, as roots kept in damp and moist soil can potentially grow fungus. However, it is important to water the plant (link to watering bonsai page) consistently, especially when there is a lot of foliage on the plant.

3. Temperature

Bougainvillea are best kept above 40 degrees Fahrenheit; anything below this temperature must be monitored or moved to a warmer area. When pruning or potting, wait for a temperature of approximately 50 degrees Fahrenheit.

4. Pruning

Pruning is advised to shape the plant as needed; however, caution must be taken to avoid damaging the plant. Pruning should not be done while the plant is dormant; the best time to prune is when it is healthy and in active growth. It can be reduced and cut to one or two leaves.

New branches can be trained to take shape on a wire, but older ones become thick and cannot be shaped without breaking. Except for formal upright (link to bonsai tree styles page), you can shape the viney plant whichever way possible.

5. Diseases & Insects

Bougainvillea are generally protected from all pests except aphids. The main cause of death for this plant is fungus, which forms on its roots due to overwatering. Also, keep a lookout for the usual garden pests.

Control of Thrips and white fly pests

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. White flies 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.

Chemical Control of Pests

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 of Pests

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.
While wearing gloves, remove the aphids by hand, or use a sharp stream of water to knock them off the plant.
Cut away and dispose of infested foliage.
Capture flying aphids by placing yellow sticky traps near infected plants.
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.
Hit the aphids directly with above mixture and spray entire plant thoroughly.
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.
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.
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.

Bougainvillea Pests & Diseases

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, black fly or plant lice, aphids are minute plant-feeding insects. Important natural enemies include the predatory ladybugs/ladybirds/lady beetles, 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.

Tips For Growing Bougainvillea In Containers:

Bougainvillea is a hardy tropical vine that grows in areas where winter temperatures remain above 30 degrees F. (-1 C.). The plant usually produces three rounds of vibrant blooms in spring, summer and autumn. If you don’t have growing space or live in a suitable climate, you can plant bougainvillea in a pot. If you live in a chilly climate, bring potted bougainvillea plants indoors before the first frost. Bougainvillea for Pots Several bougainvillea varieties are suitable for growing in containers. “Miss Alice” is a shrubby, easily pruned variety with white blooms. “Bambino Baby Sophia,” which provides orange blooms, tops out at about 5 feet. If you like pink, consider “Rosenka” or “Singapore Pink,” which you can prune to maintain container size. Red varieties suitable for container growing include “La Jolla” or “Crimson Jewel.” “Oo-La-La”, with magenta-red blooms, is a dwarf variety that reaches heights of 18 inches. “Raspberry Ice” is another variety suitable for a container or hanging basket. If purple is your favorite color, “Vera Deep Purple” is a good choice. Growing Bougainvillea in Containers Bougainvillea performs well in a relatively small container where its roots are slightly restricted. When the plant is large enough for re-potting, move it to a container only one size larger. Use a regular potting soil without a high level of peat moss; too much peat retains moisture and may result in root rot. Any container used for growing bougainvillea must have at least one drainage hole. Install a trellis or support at planting time; installing one later may damage the roots.