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Beetle That Has Killed Palm Trees In San Diego County Could Spread

June 27, 2017 1:20 p.m.

Beetle That Has Killed Palm Trees In San Diego County Could Spread


Mark Hoddle, director, Center for Invasive Species Research at UC Riverside

Related Story: Beetle That Has Killed Palm Trees In San Diego County Could Spread


This is a rush transcript created by a contractor for KPBS to improve accessibility for the deaf and hard-of-hearing. Please refer to the media file as the formal record of this interview. Opinions expressed by guests during interviews reflect the guest’s individual views and do not necessarily represent those of KPBS staff, members or its sponsors.

This is KPBS Midday Edition I am Maureen Cavanaugh. The health of San Diego's urban tree population has been under assault in recent years. Now comes news of an added threat which may be the most dangerous problem for our region's palm trees. The south American palm Weevil has killed dozens of homes. It is native to the proper -- traffics -- topics but is new to the US. Entomologist from the center for invasive species research has been studying and tracking the south American palm label and -- Vernita -- Weevil entrance is now.
Thank you.
The date palm is the tree that this Weevil likes to invest.
This is an iconic landscape home -- palm in Southern California. Most people are familiar with it because it looks like a pineapple. If you look at the trunk and needs to the base of the palm tree has had the fronts pruned off of it it looks like a pineapple you are looking at a Canary Islands date palm. The female Weevil has a long snout and uses it to drill a hole into the crown of the palm tree and they lay their eggs in the tunnel and the larva can grow to three inches in length and basically destroys the internal parts of the palm and causes the fronts to fallout and the crown will drop off and you are left with a palm trunk with a halo of dead fronds that the top.
Cannot be brought back to health?
Once the damage has been done to the crown it is impossible to save the tree. What we are looking at now is that it is possible to protect palm trees using pesticides.
How widespread is the infestation.
We do not know how far it has spread out of Tijuana but we know that it has spread at least as farm -- far as Chula Vista San Diego County but we do not know how far west or east it has spread and we are asking the public to help us with surveys to pin down just how far it has spread down.
What kind of damage has the South American Weevil done to Tijuana.
If you visit today you will see many around the parks and pauses that are dead. There are no funds apparently to take down this palm tree so they are basically living or dead statutes to the attack of the palm weevil.
You mentioned pesticides. How would you go about protecting your trees if you have date palms from infestation.
Detecting a palm tree with the pesticide is very difficult and's applications by a certified pesticide applicator. There are certain ways that this can be applied. Compounds that kill the weevil some contact can be applied to the fronts. When they fly there to attack it they touch the pesticide. They will kill the weevils. Alternatively pesticides can be applied into the soil are even injected into the trunk of a tree. These are translocated and moved inside the palm into the crown whether weevil are feeling -- feeding. They get a lethal dose of insecticide moving through the palm tree.
You just said that the weevil is moving into San Diego. We do not know how far it has spread. You are trying to track how the weevil is spreading.
We are studying how far can play. To do this we are using computerized flight mills. The ice are aerial treadmills that we attach it to. As we fly the computer records how far it is flying. The fly in a circle on a machine that we have dealt especially for this purpose. Some of the data we have collected so far suggests that they may be able to fly on average about 15 miles per day. For them to have flown from Tijuana to San Ysidro were the first infestations in San Diego County were found is only about a three or so mile flight it is very easy for the weevil to do.
You are expecting it to spread to other parts of California?
Yes we are expecting it to spread and possibly one or two ways. It will either fly on its own as we go through the landscape looking for new palm trees to invest or another way it could be moved another long distance would be through the movement of life palm trees that are infested with weevils. The transplantation of life owns in California is a big business and it allows people to instantly landscape new gardens around homes shopping Mars -- malls or hotels. Some of the palms that have been moved out if they have weevils inside them you will create a new infestation in and area that could be some considerable distance from the source.
Our public officials taking note of your research. Do you have any suggestions about what they can do to combat this read of this weevil -- spread of this weevil.
The Commissioner's office is aware of the infestation and are coordinating a response to deal with the infestation. A lot of the work that we are doing is through lack of funding. Without support we cannot get out to monitor just how widely spread the weevil is or ramp up control. It is for controlling these urban infestations and there's no funding to do the work we need to do. We are doing the best we can with very few resources.
I have been speaking with the director for the Center for invasive species resort -- research at UC Riverside. Thank you.
Thank you.