What is killing our Canary Island Date Palm trees?

As we enter 2021 and look at the movement of South American Palm Weevil (SAPW), Rhynchophorus palmarum (L.) The speed of spread Northward and death rate of Canary Island Date Palms is very alarming.

We have known for some time (2012) when the SAPW first starting invading the border areas of San Diego that the natural movement Northward was inevitable.

Slowly but very surely the SAPW has been moving Northward, killing hundreds and hundreds of our Canary Island Date Palms (Phoenix canariensis).

As the South American Palm Weevil invades more urban and residential areas of our county people are now waking up and asking, “What is Killing the Palm trees?”

The South American Palm Weevil is responsible for countless Canary Island Date Palm deaths throughout the southern section of San Diego and sadly it looks like 2021 will be no different.
Since 2017 we have used our mapping software to track the movement of the weevil and I wanted to show you not only the speed of the movement but where we are currently seeing Canary Island Date Palm deaths.

Here is at the end of 2017. Mainly South of the 8 freeway.

By the end of 2018, the SAPW established and killed hundreds of Canary Palms in Imperial Beach, Bonita and Chula Vista areas.

By the end of 2019, you can see the SAPW moving North to Downtown San Diego, Old Town and Balboa Park areas, but still mostly South of the 8 freeway.

By the end of 2020 the SAPW jumped over the 8 Freeway and began killing palms in Mission Beach, Pacific Beach, La Jolla and 1 death in Rancho Santa Fe

Now as we are 1 week into 2021, the SAPW is making it’s presence felt in the Point Loma, La Jolla areas and starting to be more visible in the Rancho Santa Fe and Del Mar areas.

By

Also you will notice on the last 2021 map additional palm species
Here is a side by side from 2017-January 2021
2017
2021
In late December 2020 we verified a Chilean Wine Palm (Jubaea chilensis) in Mission Bay area that died due to the South American Palm Weevil.
Chilean Wine Palm (Jubaea chilensis).
Entry holes found of the base of the fronds.
View from the top of the palm. The meristem is gone.
This was recovered from the palm.
Adult SAPW.
Another palm death. Sad!
According to UC CISR the actual known potential host list for the SAPW the following:
  • Coconut Palm (cocos nucifera)
  • African Oil Palm (Elaeis guineenis)
  • Acai Palm (Euterpe oleracea)
  • Sago Palm (Meteroxylon sagu)
  • Canary Island Date Palm (Phoenix canariensis)
  • Date Palm (Phoenix dactylifera)
  • Fan Palm (Washingtonia spp.)
  • King/Queens.Royals (Archontophoenix/Syagrus/Roystonea spp.)
And we verified a Chilean Wine Palm (Jubaea chilensis) that was not on the known host list.
So it’s a bit obvious to say that the Palm Weevil will feast on more than just the popular Canary Island Date Palm (Phoenix canariensis).
Management options and recommendations:
A few notes that we have found in our 5+ years of managing the SAPW:
  • Canary Island date Palms are the preferred Palm, with the likelihood of other Palm species being attacked.
  • Treating the Palm with Systemic insecticides at 3-4 month intervals seems to get us the best results. Treating at this interval is giving showing about 97% survival rate.
  • Having the ability to treat the crown (meristem) of the Palm where the SAPW is feeding is the most effective form of control. Not treating the crown (meristem) is showing a lesser ability to prevent new SAPW attacks.
  • Limiting trimming to the Palm in the “peak activity” months of Spring, Summer, early Fall is ideal. SAPW can be attracted to fresh cuts.
  • Monitor, Monitor, Monitor and treat your palm. Early detection symptoms are very hard to spot and commonly by the time you see that your palm is attacked, it can be too late.

See below some progression pictures.

Focus on the top / middle meristem areas.

A

B

C

D

E

F

Out of all these pictures, we were able to save the palm on picture A, as we treated right away with a systemic crown spraying as well as soil systemic.

See all the new growth coming in.

Here is another example where we treated at an early stage of visible decline.

See the missing meristem.

Canary Palm showing early signs of decline in the meristem area.

Here is 12 months later after 4 treatments. New health growth. You can also see the old damaged growth.

So in conclusion:

  • The SAPW is well established in the South region of San Diego, with La Jolla area being the most Northern “hot spot”.
  • Along with The Canary Island Date Palm, Chilean Wine Palm, Dactylifera Date Palms and possibly Queen palms are viewed as the next target of SAPW.
  • Early detection of SAPW is very difficult to diagnose.
  • As of 2020 adult SAPW has been caught in monitor stations as far North as Carlsbad and San Marcos.
  • With our weather, the SAPW has shown the ability to be active year round. 65 Adults weevils were captured at Balboa Park just in the month of December. In the peak months of  Summer, upwards of 200-250 Adults were captured.
  • Preventatively treating your Palm with systemic insecticides at 3-4 months will help keep your palm from being attacked.
  • If you opt to not treat your palm, you should make a plan to remove your Palm because it will be a short time before it’s attacked by the SAPW.

Any additional questions or interested in getting your palm on a preventative program, please call or email.

760-294-APC7(2727) or email us at info@apcphc.com