How to Identify Caterpillars on Plumeria (Including Frangipani Worm)

Caterpillars are among the most dramatic pests to affect plumeria. Unlike sap-sucking insects that quietly weaken the plant, caterpillars can rapidly strip leaves, leaving bare stems behind. The most common offender is the Frangipani Caterpillar (Tetrio sphinx moth larva), but other chewing larvae may appear seasonally. Recognizing their presence early—before they defoliate your plumeria—is the key to successful management.

This guide covers how to identify caterpillars, the signs they leave behind, and how to distinguish their damage from other plumeria pests.

What Are Caterpillars?

Caterpillars are the larval stage of moths or butterflies. On plumeria, the most common are:

Frangipani Caterpillar (Pseudosphinx tetrio)

• Large (up to 5–6 inches long)
• Black body with bold yellow rings and a red-orange head and tail
• Very noticeable and feed in groups on plumeria leaves
• Larvae of the Tetrio sphinx moth, found in Florida, the Caribbean, Central America, and other tropical zones

Other Occasional Caterpillars

• Smaller green or brown caterpillars that chew holes or scallop leaf edges
• Armyworms or cutworms (rare, usually affect seedlings or potted plants)

Why Caterpillars Are a Problem

• Defoliate plants rapidly, sometimes within 24–48 hours
• Reduce energy reserves needed for blooming or root growth
• Weaken young or newly rooted plumeria
• Large frass (droppings) attract ants or mold and indicate heavy feeding
• May return in cycles during warm months

Where and When to Look

Caterpillars prefer warm, humid weather and tend to feed:

• On leaf edges, moving inward
• In clusters during early development
• In the morning and evening, hiding during midday heat
• On upper and outer foliage, especially after summer rains

Inspect:

• Leaf margins for missing sections
• Stems for black frass droppings (small cylinders)
• Branch tips for feeding clusters (early instars group together)

Visual Signs of Caterpillar Damage

1. Chewed Leaves

• Jagged or scalloped edges
• Midribs often left behind after full leaf is eaten
• Multiple leaves missing overnight is a strong indicator

2. Large Black Frass (Droppings)

• Found on leaves or soil below the plant
• About the size of a peppercorn or pencil lead
• May be clustered near feeding sites

3. Visible Caterpillars

• Often grouped together early on
• Easy to see by mid-size (2–3 inches)
• Bright coloration and size make Frangipani Caterpillars unmistakable

4. Sudden Leaf Loss

• Entire tree or branch may be bare by the time damage is noticed
• Most common on plumeria left unattended for several days in summer

Frangipani Caterpillar vs. Other Pests

When Caterpillar Activity Peaks

• Late spring through summer, especially in tropical climates
• After rains, when moths lay eggs and foliage is plentiful
• During plumeria blooming season, when trees are leafed out
• Often multiple cycles during warm months if unchecked

Additional Identification Tips

• Look up during inspection – caterpillars start at the top and work down
• Check surrounding soil and mulch for frass or crawling larvae
• Flashlight inspection at dusk can reveal evening feeding

Conclusion

Caterpillars, especially the bold Frangipani Worm, can do serious damage to plumeria foliage if not spotted early. Watch for scalloped leaves, large black droppings, and clusters of larvae on outer branches. With daily or weekly observation during warm months, you can prevent major defoliation and keep your plumeria growing strong. In the next article, we’ll explore how to treat caterpillars on plumeria with safe, effective methods—both organic and chemical.