One of Los Angeles' quintessential icons - palm trees - are being threatened by an invasive pest from overseas - the South American palm weevil. KQED Science produced a clever overview on the life and times of this devastating pest, punctuating it with a surprise ending that features UC Cooperative Extension specialist Mark Hoddle.
The story outlines the pest's life cycle, which starts when a female lays its eggs in the crown of a palm. They hatch and larvae eat the plant from the inside out, eventually killing the palm. The larvae pupate, complete metamorphosis, then fly off to find another palm to attack.
Hoddle conducted an experiment to determine how far the weevils can fly. He glued the pest on a sort of insect treadmill and let it fly in circles. He found that they can travel up to 15 miles a day, enough to easily hopscotch from palm to palm on their own and spread widely.
The biocontrol scientist demonstrates one way to get rid of South American palm weevils. If you're not squeamish you can view the video on the KQED website.
Communities in Southern California are watching their valued landscape palm trees suffer mortal damage from an invasive pest that is making its way northward from Mexico, reported Marty Graham in San Diego Reader. The South American palm weevil lays eggs in the palm tree's crown, where its grubs destroy tissue that holds the fronds.
"The first sign of infestation is seeing the crown droop and turn brown," said Mark Hoddle, UC Cooperative Extension biological control specialist at UC Riverside. In time, the crown can fall off.
"The crowns weigh a couple of hundred pounds and, if they fall on something like a car or house, they can do considerable damage," Hoddle said.
For now, the pest appears to be focusing on Canary Island palms, but have been known to lay eggs in other ornamental palms and date palms.
"I hate to think of what could happen if they reach the palm oases in the Anza-Borrego Desert," Hoddle said of the treasured California native palms that grow in Southern California desert canyons.
South American palm weevil is a relatively large pest capable of flying substantial distances.
"We've tested their flying capacity and our data suggests it can fly quite far," Hoddle said. "It's potential territory in California and the Southwest is enormous."
The only control measure at the moment is repeated treatment with pesticides.
"There are palm trees in the Mediterranean with PVC pipes up the side and a shower head at the top where a pump blasts pesticides every few months," he said. "There are also systemic pesticides you can put in the tree roots."
For more information or to report a possible South American palm weevil infestation, see the Center for Invasive Species Research website.
Southern California's iconic palm trees are now threatened by another invasive species, the South American palm weevil, reported Mark Muckenfuss in the Riverside Press Enterprise.
Mark Hoddle, UC Cooperative Extension specialist based at UC Riverside, has been monitoring the pest south of the border and recently visited Tijuana to assess the infestation.
"We found about 130 dead Canary Island palms," Hoddle said. "It's been devastating in Tijuana."
On the way back to Riverside, he stopped in Chula Vista, where he noticed dead palm trees.
“I thought, ‘What the heck?' and yeah, it was there, too,” he said. “It was basically an accidental discovery.”
Hoddle recently reported in California Agriculture journal on the successful eradication of a different invasive beetle attacking palm trees in Laguna Beach, the red palm weevil. The cost of the eradication was more than $1 million.
In the Press Enterprise article it said the South American palm weevil is susceptible to insecticides and pheromone traps. If the beetle's presence in a palm is determined quickly, the tree can be saved.
Hoddle said he is concerned about the scope of the South American palm weevil infestation in Southern California.
"My personal feeling is we might be on the verge of a crisis now," Hoddle said in a press release issued by UC Riverside. "The big problem is we don't know how far the weevil has spread. We really need help from the public in tracking its spread."
To report a South American palm weevil find, call the CDFA pest hotline at (800) 491-1899, or you can contact your county agricultural commissioner's office.
Introduction of new invasive pests into California seems to be increasing, reported Todd Fitchette in Western Farm Press. The story was based on presentations at the recent professional crop advisors convention in Anaheim by UC Cooperative Extension specialists Mark Hoddle and UC Riverside entomology professor Richard Stouthamer.
Before 1989, Hoddle said, California saw about six new pest invasions per year. The number has risen to about 10 per year, and the cost amounts to about $3 billion annually.
Asian citrus psyllid, a relatively recent invader in California, has farmers particularly worried because of the pest's ability to spread the lethal bacterial disease huanglongbing in citrus. In late 2011, Hoddle's lab began releasing a natural enemy of the psyllid he collected in the Punjab, Pakistan, a stingless wasp called Tamarixia radiata.
According to the Western Farm Press article, Hoddle is now studying a second natural enemy of ACP - Diaphorencyrtus aligarhensis - in quarantine at UC Riverside.
Stouthamer is studying another troublesome invasive pest in California, the polyphagous shot hole borer. The pest attacks many tree species that shade California streets, landscapes and parks; their greatest threat to agricultural production appears to be in avocados.
At the meeting, Hoddle said there is a growing and vocal minority of ecologists who believe invasive species are not such a serious problem, Fitchette wrote.
“They think we should just relax and let them install themselves in the environment and do whatever they like,” Hoddle said. “I think that's a wrong viewpoint to be taking with a lot of these organisms.”
The birds, which numbered in the millions 100 years ago, are now down to about 145,000 in all. One reason for the decline, the article said, is the agricultural harvest. Before agriculture dominated the landscape, the birds nested in the valley floor's native tules, shrubs and grasses. The birds adapted to nesting in the vast fields of wheat, oats and other crops grown to feed dairy cattle. However, when the crop is harvested, many birds are caught up in the equipment, said Robert Meese, a researcher in the Department of Environmental Science and Policy at UC Davis.
The USDA is working with dairy owners to protect the young birds and some dairy operators are voluntarily delaying harvest until the baby birds can fly away, the article said.
In San Diego, the Board of Supervisors is coming to the aid of the state's ailing bee population, said an article by Mark Walker in the San Diego Union-Tribune. The board has voted to open up county land for beekeepers who are finding it hard to place bees in areas where they can forage for nectar.
The county wants to foster more beekeeping in the face of dwindling populations from the mysterious colony collapse disorder. More hives could help honey production and farmers who need bees for their crops, the article said.
Another insect - this one a pest - is the subject of stunning photos in a recent National Geographic feature. Photographer Sam Droege of the USGS Patuxent Wildlife Research Center captured a shot of an Asian citrus psyllid pierced by the tip of a needle that shows every tiny hair on its legs and every lens of a bulging red eye.
The article reviewed some of the research now underway to prevent the spread of huanglongbing disease of citrus, a tree killing scourge that is spread by Asian citrus psyllid. Among the possible solutions are breeding Asian citrus psyllids that can't carry the disease, genetically modifying citrus to be resident and introducing natural enemies of the pest.
One natural enemy under study at UC Riverside, Tamarixia radiata, appears in a photo that's part of the NatGeo spread. The image, by David Littschwager, shows an army of Tamarixia radiata with translucent yellow abdomens artfully back lit. The wasps were first collected in Pakistan by UC entomologist Mark Hoddle, who traveled to the Middle East to collect psyllid predators in their native range. Before being approved for biocontrol use, Tamarixia underwent a lengthy USDA evaluation intended to ensure that it wouldn't harm any native psyllids. It is now being released in ACP-infested citrus trees, where they are being carefully monitored for year-to-year survival.