Bougainvilleas are fairly hardy ornamental plants that do very well in climates such as the Coachella Valley. Even though Bougainvilleas are resistant to many bugs, some insects still find this plant very attractive.
Aphids – feeds off tender new leaves. Its secretion can attract ants and promotes mold gowth
Spider mites – Leaves dropping off the plant
The Bougainvillea Looper Caterpillar – Eat the plant leaves
Mealybug – creates black, sooty-looking mold.
The most natural form of pest control for your Bougainvillea is the ladybug. It is a predator of aphids and most of the other bugs found on a Bougainvillea. You can also combine Neem tree oil concentrate with water and a bit of dishwashing liquid to create a spray. This is effective as a repellent to aphids as well as mealybugs.
If you do use a chemical pesticide, make sure to wear protective clothing and follow the directions closely. Keep in mind that pesticides not only kill off harmful insects, but they may kill off natural predators such as the praying mantis and the garden spiders that control infestation of aphids and mealybugs.