The Coastal Gardener: Destructive beetle found in Laguna Beach
Imagine the Southern California skyline without the presence of majestic date palms and tall, slender Washingtonia fan palms.
That’s what a few landscape professionals, palm enthusiasts and scientists are worried about, following the discovery last month of a destructive new pest in a Laguna Beach neighborhood.
For the first time ever, the red palm weevil, a beetle native of Southeast Asia, was discovered alive and well in the United States. The host was a Canary Island date palm in the Emerald Terrace neighborhood of north Laguna Beach.
Rhynchophorus ferrugineus is considered one of the most destructive palm pests in the world. Nick Nisson, Orange County’s entomologist at the County Agricultural Commissioner’s Office, identified the invader after a palm removal crew became curious about the unusual-looking insects.
Red palm weevils are relatively large and rusty red. Adult beetles lay about 200 eggs on the new growth at a palm’s crown. But it is its larvae that cause most of the problems for palms. Impossible to see, the juvenile larvae feed on the soft fibers inside the palm, tunneling through the trunk for about a month, before they pupate, emerge as adult beetles and fly away in search of another palm. The larva’s burrowing activity usually kills the host palm.
The beetle is a major pest of commercial coconut, date and oil palm plantations in much of the world. Originally from Asia, it spread to the Middle East in 1985 and reached the Mediterranean by the late 1980s. It was first recorded in Spain in 1994 and in France in 2006. Finally, the weevil made it to the Caribbean in January 2009.
Now it’s in Laguna Beach.
Panic has already begun among palm enthusiasts. Members of The International Palm Society are sounding the bell. Comments and warning are coming in both locally and internationally about the potential destructiveness of this pest.
Tom in Laguna Beach writes:
“Only a mile from my house. Yikes!”
A palm enthusiast from San Diego is worried:
” … the palms that are hit by the weevil can’t just be cut up and hauled away. The tree can’t even be burned, it must be buried in a pit to prevent the approximately 300 weevils per tree from getting away so the growth pattern of the infestation does not grow logarithmically. The damage caused by a few larvae of the weevil is astonishing. Even one larva may cause considerable damage, and, sometimes the death of the palm.”
Nigel from Brazil says:
"…this is a disaster, if it spreads. There doesn’t exist anything worse for palm trees. They are capable of total eradication of all Phoenix and Washingtonia (palms) in California…"
Maurice, from a Mediterranean island, provides a firsthand observation:
“Canary Island date palms getting destroyed — it was like a wave that moved through areas of the island.”
Basilios in Athens, Greece, also warns Californians:
“We’ve been hit quite hard by this weevil in Greece … about 80% of our Canary Island date palms in the area are already dead (in approximately 10 years) …"
Finally, here’s John Wilson’s comments, received from Andalucía region of Spain. Seems he sees an opportunity for a new sport:
“I destroyed 14 red palm weevils in one of our two Washingtonias, in an area where there are maybe less than a dozen palm trees in a square mile. Good luck to California. You need to be vigilant, and walk right up to any young Canary Island date palm or Washingtonia if the opportunity arises, and check it over starting from mid April through to early June.
“Red palm beetles are slow in the air, like bumble bees, so catching them is not out of the question. In your own garden, I found that swinging a garden rake was pretty effective, as they tend to veer all over the place when taking off. THWACKK!! Advantage Wilson!”
State officials have already set traps in the area near the initial discovery and are working to eliminate the threat. In the meantime, gardeners should learn to recognize the adult beetles and report possible red palm weevils to the state’s exotic-pest hotline at (800) 491-1899.
RON VANDERHOFF is the nursery manager at Roger’s Gardens, Corona del Mar
Ask RonQuestion: Could you let me know when the best time to plant a dwarf lemon tree is? I am thinking about a whiskey barrel that could be the home of a Meyer lemon or something like that.
Answer: Meyer lemon is a great choice. In my opinion, they are the best of the lemons for home gardeners. We are fortunate in coastal Southern California to be able to plant citrus just about year-round. So, if you’re anxious and just can’t wait, go ahead now. Nonetheless, the absolute best time is during the spring or early summer. Because citrus are subtropical, they love warm months and planting at the beginning of this period is perfection. In a container, I suggest using an especially fast draining, porous soil. Either mix 1/3 pumice into a high-quality potting soil or buy “cactus mix,” which will be about the same thing.
ASK RON your toughest gardening questions, and the expert nursery staff at Roger’s Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail firstname.lastname@example.org, or write to Plant Talk at Roger’s Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.