South American Palm Weevil (SAPW)

The South American Palm Weevil (Rhynchophorus palmarum) is a destructive and invasive weevil known for attacking canary island date palms in their native areas of South America, Central America, Mexico and the Caribbean. It has also become an established palm pest in San Diego county, California.

In December of 2010, there were reports of dying Canary Island palms in Tijuana, Mexico. Examination found the palms to be infested with Rhynchophorus palmarum a.k.a the South American Palm Weevil (SAPW). In 2011 the SAPW was first detected in San Diego County, just 5 miles north in neighboring San Ysidro, California. The SAPW was officially confirmed on May 9th by the USDA with several other detections taking course over the next few months spreading palm mortality throughout the border cities of San Diego.

As of January 2025, the South American Palm Weevil is active throughout most of San Diego County killing Palms and establishing new hosts along the way as far north as the 78 Highway. Monthly monitoring stations in Carlsbad and San Marcos are showing consistent adult palm weevil activity throughout the year.

The communities of Encinitas, Solana Beach, Del Mar, Rancho Sante Fe, Fairbanks and Carmel Valley are currently the most northern “hot zones” in the county of San Diego. Communities south of the “hot zone” where SAPW is now well established, are seeing many tragic palm deaths throughout these areas as well. The maps below show the progressive spread of SAPW in San Diego County from 2020 to 2024 with the growing host list detailed.

The SAPW host list continues to grow. Currently, the most susceptible and targeted hosts are the Canary Island Date Palms (Phoenix Canariensis).  As of 2025, twelve different species of Palms have been confirmed as being attacked and killed by the South American Palm Weevil.

The palm weevil continues to travel north from its origination in the southern end of the county. SAPW infestations have been located as far north as Fallbrook/Bonsall and as far west as Ramona.

South American Palm Weevils are long-nosed beetles that utilize their snouts as drills to enter a palm’s meristem. Once a male weevil finds a suitable palm, it begins feeding on the meristem and emits a pheromone to attract a female counterpart. The kairomones that are produced by wounds on the healthy or stressed palm, create a foul-smelling odor which further attracts adult SAPWs. The female weevil then lays her eggs in the snout-drilled tunnels, which provide a protective environment for the larvae to develop and then feed on the tissue of the palm from the inside out.

Once large enough, the weevil larvae feed on the crown of the palm, destroying its meristem tissue. The SAPW larvae spin cocoons from the leftover palm fibers that they cannot eat, causing the tree’s fronds to starve and die. This feeding by the larvae in the crown of the palm causes significant damage to the apical meristem and internal tissues. Soon the palm is unable to produce new fronds, resulting in the tree’s death.

the drone image to the right shows a missing meristem view from top of the palm

Above images show a Canary Palm with early signs of decline, treated right away with a contact crown spraying and soil systemic. The canary palm was showing early signs of decline by the missing meristem in the left photo. After 4 treatments in 3 month intervals the picture on the right shows old damaged growth and new healthy growth coming in.

SAPW infestation is often difficult to detect in its early stages. One early symptom is that the top or center leaves of the canopy will typically appear cut off or missing. The center of the canopy, which is often difficult to view from ground level, can be seen with our drone technology.

Infested palms often show a progressive lightening and wilting of the foliage. The infestation that occurs at the leaf bases can show signs of tunnels or grooving which are often filled with cocoons from SAPW larvae. The tunnels appear as holes where they travel from one leaf base to another. Larvae bore into the trunk and can completely destroy the internal tissue of a palm in as little as 6 weeks.

Once established in the center leaves, the infestation moves into the apical meristem. This causes the death and collapse of the center leaves, preventing any future growth. Fronds often droop or turn brown in color. Because the structural damage is at the leaf base area, the leaves often collapse or fall easily. The iconic, normally upright palm fronds then begin to tilt and collapse.

The rot damage caused by larvae feeding can be so severe that trunk tissue is compromised, and the canopy can easily fall off. The destruction of internal tissues and apical meristem results in the death of the palm. Adult South American Palm Weevils then emerge and travel to other palms, seeking their preferred habitat among the tightly packed palm leaf bases.

Prevention is key because once a palm is “attacked”, the chance of survival is low. Preventative insecticidal applications are recommended to be made every 3 months throughout the year and have shown the best results in preventing future attacks. Insecticide treatments alone do not guarantee Palm survival.

Contact our team of arborists here in southern California if you need pest control for palm weevils. If you have any additional questions or concerns about your palms, feel free to reach out to our team of experts via the link below