The Canary Island palms that line Southern California’s streets, particularly in La Jolla and elsewhere in San Diego County, are disappearing at an alarming rate.
Many of these majestic trees, some as old as 80 to 100 years, have long been a staple of our landscape. As their numbers dwindle, we are left wondering: Can we stop this loss? And can we learn something from the Canary Islands, where these palms originate?
I have been visiting the Canary Islands and I’ve observed something remarkable. Like California, this region also struggles with the palm weevil, a destructive beetle that has decimated palms in San Diego County.
Despite the challenges, the Canary Islanders have found a simple yet effective method to protect their beloved palms.
The palm weevil targets newly cut fronds, boring into the exposed soft tissue. To prevent this, the Canary Island locals apply a layer of red plasticized paint over the freshly cut fronds, sealing the area and blocking the weevils’ entry. This straightforward solution has saved hundreds, if not thousands, of palms across the islands.
Could this be the key to preserving our palms in Southern California?
The Canary Islands are a Spanish archipelago about 60 miles off the coast of Morocco. The islands, the southernmost region of Spain, are the largest and most populous of the Macaronesia region. Their rich history dates to the 15th century, when they were colonized by Spain, and they remain a crucial hub for internationaltrade.
Originally home to the indigenous Guanches, the Canary Islands now serve as a meeting point for cultures from Africa, Europe, North America and South America.
The Canary Island date palm is native to these islands. It became one of the most widely cultivated ornamental palms in the world during the mid- to late 19th century. Sadly, these beautiful trees are under attack by the palm weevil.
A weevil has a life cycle consisting of four stages: egg, larva, pupa and adult. The female lays more than 200 eggs in hidden spots on the palm tree. After hatching in just a few days, the larvae feed on the tree’s soft internal tissues, eventually killing the tree. The larvae grow up to 5 centimeters before undergoing metamorphosis inside the pupa, transforming into adult insects. The entire life cycle can last up to 200 days, with adult weevils living 45-90 days.
Various biological methods have been tested to combat the weevil. These include using insect-pathogenic nematodes that attack the larvae and adult weevils, a treatment known as natusys to strengthen the palm tree’s defenses, and pheromone traps to capture adult weevils as a preventive measure.
While these methods have had some success, it may be time to adopt the Canarian approach with the red paint to halt the infestation in its tracks.
It’s heartbreaking to see these iconic trees slowly disappear. The Canary palms have long been a symbol of beauty in Southern California. With the red plasticized paint technique, we have the potential to save many more palms and preserve the lush landscapes of La Jolla and beyond for future generations.
Nile Regina El Wardani is a lecturer at the Global Health Institute at UC San Diego in La Jolla. ♦
