The Florida palmetto weevil (Rhynchophorus cruentatus ) can be a problematic species in stressed palms and palms that are transplanted. This native species is the largest weevil in the United States. The palmetto weevil can be identified by its long snout or rostrum. There can be different color variations. Some weevils are solid black while some are red and black.
The palmetto weevil has a complete life cycle; egg, larvae, pre-pupae, pupal, and adult stage. Eggs are laid on bases of the leaves or in a wound of the palm. The larvae or grubs feeds on the soft apical meristem and when mature they pupate. The whole lifecycle can take as long as 84 days. The damage from the grubs to the apical meristem can be fatal.
Symptoms vary. The most common is the collapse of the crown. Insecticidal treatments after a infestation can be difficult because by the time the damages is seen, it is usually too late. The infested tree should be cut down and the beetles destroyed before spreading to another palm. Sanitation is very important in growing healthy palms and preventing unwanted pests. Preventative treatments are possible, but can be very costly and time consuming.
As in most pest management programs, a integrated approach is the best route. Growers should increase vigor by fertilizing, pruning and irrigating correctly. Growers should also practice the Florida-Friendly Landscape principle of Right Plant, Right Place. Growing Christmas tree palms, foxtail or royal palms here in Central Florida can increase risks.
If you suspect palmetto weevils, call your local UF/IFAS Extension Agent. Collecting samples would be ideal. Place either the grubs or adults in a vial of rubbing alcohol and bring them to the Extension office. From there, the agent can provide any assistance and positive identification. For more information, please visit https://edis.ifas.ufl.edu/in139