Distinctive and elegant plumeria blossoms are highly prized for their colors and shape. Although the bright flowers, traditionally used in leis, are the visual stars of the plants, the less showy green leaves require care and attention as well. Bugs on the surface of plumeria leaves indicate a pest infestation that threatens the health of the plant. Identifying and eradicating the pests are critical to ensure the long-term survival of the plumeria. These tropical beauties grow as shrubs or trees in Sunset Garden Zones H1 and H2. On the mainland, depending on the variety, plumerias grow in zones 12, 13, 19 and 21 through 24.
The tropical plumeria is particularly resistant to bugs and mites. If a pest makes its way to the leaves of your plumeria, the plant can withstand a considerable amount of infestation damage before its health is negatively affected. Despite high resistance, plumerias are not immune to disease or infestation, and if left untreated, a pest problem can overtake and kill the plant.
If you notice bugs on the plumeria leaves, they are likely spider mites, whiteflies or mealybugs. Leaves infested with bugs are likely to wilt, droop or turn from green to yellow or gold. Small white bugs and delicate webbing on the underside of the plumeria leaves are telltale signs of a spider mite infestation. A sticky or waxlike coating on the leaves coupled with small, white bugs is indicative of mealybugs, which leave behind a honeydew secretion. Whiteflies deposit a similar residue but feature rounder bodies than mealybugs.
Eliminating a slight-to-moderate infestation on plumeria leaves is relatively simple. If you spot only a few mealybugs on the leaves, wet a cotton swab with rubbing alcohol and dab the bugs and the affected area. For spider mites or whiteflies, direct a forceful blast of water from a garden hose at the affected leaves to wash away the bugs; you may need to repeat the treatments over a few weeks, but water washing eliminates the need for harsher treatments that may affect surrounding plants and soil. If water treatments aren't effective, or the pests return, an insecticidal soap will eliminate the bugs. Reserve systemic insecticides for extreme cases to limit chemical exposure.
After you've eliminated the pests, reduce the risk of recurrence with routine leaf checks. Even if you don't see any adult bugs, scan the leaves for larvae or eggs. Wipe the leaves down or apply a horticultural oil to eliminate the immature pests. When watering plumeria, wet the leaves as well to discourage bugs from returning to the plant.
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