The Plumeria Pests and Diseases Guide is an essential resource for identifying, preventing, and treating the most common threats to plumeria plants, including pests, fungi, and environmental stressors. This guide offers detailed information on how to recognize early signs of trouble, from insect infestations to fungal infections, and provides practical solutions to address these issues. It also covers strategies for managing environmental factors such as excessive humidity, temperature fluctuations, and poor soil conditions, which can weaken plumeria. With expert tips on natural and chemical treatments, as well as proactive care practices, this guide ensures your plumeria remains healthy, resilient, and free from common ailments, allowing it to thrive season after season.
How to Identify Root Weevils on Plumeria – Leaf Notching, Larval Root Damage & Hidden Signs
How to Identify Root Weevils on Plumeria – Leaf Notching, Larval Root Damage & Hidden Signs
Root weevils are two-part plumeria pests: the adult insects chew distinctive notches into leaves, while the larvae feed on root tissue underground—often going unnoticed until the plant begins to wilt or decline. These nocturnal pests are difficult to spot directly, but their damage provides clear clues if you know what to look for.
This guide covers how to identify root weevils and their larval stages on plumeria, helping you catch infestations early before significant root damage occurs.
What Are Root Weevils?
Root weevils are beetles belonging to the family Curculionidae. On plumeria, the most common suspects include:
- Black vine weevil (Otiorhynchus sulcatus)
- Sri Lankan weevil (Myllocerus undecimpustulatus)
- Other generalist tropical weevil species
Life Stages:
- Adult beetles: Chew foliage at night
- Larvae (grubs): Live in soil, feed on roots
- Pupae: Develop in soil before emerging as adults
Symptoms of Root Weevil Infestation
1. Notched Leaf Edges (Adult Feeding)
- Clean, semi-circular notches along the edges of mature leaves
- Most visible in the middle to lower canopy
- Feeding occurs at night, beetles hide during the day
2. Wilting or Stunted Growth (Larval Root Feeding)
- Plumeria appears weak or wilts during hot days despite moist soil
- Growth slows, flowering declines
- May resemble nutrient deficiency or drought stress
3. Root System Decline
- Unpotting reveals thinned, chewed, or darkened roots
- Fine root hairs often missing
- Root ball may appear loose or unanchored
4. Visible Larvae in Soil
- White to cream-colored grubs with brown heads
- C-shaped, legless, ¼–½ inch long
- Found near root tips or in top 4–6 inches of soil
5. Soil Crusting or Beetle Frass (Advanced Cases)
- Light granular frass or soil castings may appear at soil surface
- In moist conditions, larvae may push up when disturbed
When and Where to Inspect
Best Times:
- Evenings or early morning for adult beetle sightings
- Spring through early fall for larval activity in soil
- During repotting, transplanting, or when wilt symptoms appear
Inspection Zones:
- Leaf edges (for feeding damage)
- Soil surface and drainage holes
- Root zone (remove gently and rinse soil to inspect)
- Under pots, bricks, mulch, or shaded areas nearby
Root Weevils vs. Other Plumeria Pests
| Symptom | Likely Cause | How to Tell |
|---|---|---|
| Leaf notches + night feeders | Root weevils | No slime, only chew marks on edges |
| Jagged leaf edges + slime | Snails/Slugs | Presence of slime trails and night feeding |
| Sudden wilt + hollow roots | Root mealybugs or rot | Mealybugs leave cottony residue; rot smells bad |
| Wilting + stunted growth | Nematodes or weevils | Nematodes create galls; weevils chew roots |
Tools for Detection
- Headlamp or flashlight for night inspection
- White paper test to catch crawling beetles
- Trowel or soil knife to expose larvae
- Hand lens to examine leaf margins for feeding patterns
Conclusion
Root weevils quietly attack plumeria from both above and below—adults leave notched leaf edges, while larvae chew the roots out of sight. Recognizing the combination of symptoms (especially leaf damage + wilting) is key to early detection. In the next article, we’ll explore how to treat root weevil infestations in plumeria using organic, biological, and soil-safe methods.