Bismarckia nobilis and RPW

[pietropuccio]

Bismarckia nobilis and Rhynchophorus ferrugineus (RPW)

after resisting for years the continuous attacks of the Rhynchophorus, in the end it succumbed:

The larvae:

[HtownPalms]

What a shame. 

[PalmatierMeg]

So sad. We have a native palm weevil that usually attacks Sabals but loves Bismarckias too. We lost our largest Bizzie to them a few years. Those grubs nauseate me.

[sonoranfans]

I lost a bizzie(20' plus overall) to palm weevil.  The palmetto weevils do attack sabal palmettos, but typically only sick ones, seems like 1/50 or less gets hit, none in my neighborhood.  My bizzie was water logged by a neighbors broken irrigation system and 21 days of rain in a row while being located in a low drainage spot.  It wasnt looking very happy with the water sometimes submerged an inch or two.  2-3 weeks later it started to blanch at the very top leaf.  Plant defenses against herbivores involve emission of volatile insect repellent organic molecules called terpenoids, and the increase in terpenoids is accompanied by rising chemistry in leaves of toxic peroxides and enzymes.  When a plant is sick or badly stressed, it doesnt produce those same vigorous immune responses to herbivore insect attack.  If a plant is genetically adapted to its environment and its predator insects, there is often a balance in nature where the healthy plant defends itself successfully to survive as a species, while unhealthy ones perish.  With palms being introduced to many unfamiliar environments, -often under stress- we can expect to have insect/pathogen casualties.  Sometimes the plant is intoduced into an environment with predators/pathogens it has not seen or adapted to, and sometimes those predators/pathogens are carried to environments they are not native to.  At this point with more knowledge of disease and insect damage, my strategy is to manage plant stress so I am not contributing to the decline of natural plant defense.  After that its up to the plant.  But if your palm is over or under watered or nutrient/micronutrient deficient, its likely making it a more preferred target of insects.   In my area I doubt you can underwater a bizzie unless its planted in pure sand in full sun.  Bizzies are planted all around my area in public plantings, sometimes 20+ in a row or interspersed with royals.  All along the I75 there are hundreds.  It will be interesting to see what their survival rate is.  For now I still have one beautiful bizzie,which also didnt like the 21 days in a row of train, but its happy now.   I'm not sure what the future viability of bizzies or sabals is in my area, but I''l be watching for plant stress and trying to cope with that.  I did learn a lesson on palm placement: dont place bizzies in drainage low spots, frequent watering areas(in grass), or borders where irrigation failure is beyond my ability to correct.  Those areas I put the wet loving palms in.  these are ideal spots for royals and wet loving palms, but not bismarckia.

[gilles06]

Pietro all your palms will die... if you don't use treatment.

[pietropuccio]

Hi Gilles,
I treated with imidacloprid about every six months, unfortunately I skipped one last year.

[Phoenikakias]

On 12/16/2019 at 5:28 PM, sonoranfans said:

I lost a bizzie(20' plus overall) to palm weevil.  The palmetto weevils do attack sabal palmettos, but typically only sick ones, seems like 1/50 or less gets hit, none in my neighborhood.  My bizzie was water logged by a neighbors broken irrigation system and 21 days of rain in a row while being located in a low drainage spot.  It wasnt looking very happy with the water sometimes submerged an inch or two.  2-3 weeks later it started to blanch at the very top leaf.  Plant defenses against herbivores involve emission of volatile insect repellent organic molecules called terpenoids, and the increase in terpenoids is accompanied by rising chemistry in leaves of toxic peroxides and enzymes.  When a plant is sick or badly stressed, it doesnt produce those same vigorous immune responses to herbivore insect attack.  If a plant is genetically adapted to its environment and its predator insects, there is often a balance in nature where the healthy plant defends itself successfully to survive as a species, while unhealthy ones perish.  With palms being introduced to many unfamiliar environments, -often under stress- we can expect to have insect/pathogen casualties.  Sometimes the plant is intoduced into an environment with predators/pathogens it has not seen or adapted to, and sometimes those predators/pathogens are carried to environments they are not native to.  At this point with more knowledge of disease and insect damage, my strategy is to manage plant stress so I am not contributing to the decline of natural plant defense.  After that its up to the plant.  But if your palm is over or under watered or nutrient/micronutrient deficient, its likely making it a more preferred target of insects.   In my area I doubt you can underwater a bizzie unless its planted in pure sand in full sun.  Bizzies are planted all around my area in public plantings, sometimes 20+ in a row or interspersed with royals.  All along the I75 there are hundreds.  It will be interesting to see what their survival rate is.  For now I still have one beautiful bizzie,which also didnt like the 21 days in a row of train, but its happy now.   I'm not sure what the future viability of bizzies or sabals is in my area, but I''l be watching for plant stress and trying to cope with that.  I did learn a lesson on palm placement: dont place bizzies in drainage low spots, frequent watering areas(in grass), or borders where irrigation failure is beyond my ability to correct.  Those areas I put the wet loving palms in.  these are ideal spots for royals and wet loving palms, but not bismarckia.

Tom I do not feel like I can share your experience also in my place.  In many instances the more pristine and vigorous palm specimens are those, which are preferably infested. This obviously doubles the shock of the grower caused by the demise of the palm.

[Phoenikakias]

34 minutes ago, pietropuccio said:

Hi Gilles,
I treated with imidacloprid about every six months, unfortunately I skipped one last year.

Six months before next treatment is a very long intermittent period! I agree that we can use only three times within a year imidacloprid, in order to avoid the development of resistance to it, but in the past we could use also other neonicotinoids like thiamethoxam and different groups of insecticides like chlorpyrifos or Dimethoat or pyrethrins. 

[sonoranfans]

17 hours ago, Phoenikakias said:

Tom I do not feel like I can share your experience also in my place.  In many instances the more pristine and vigorous palm specimens are those, which are preferably infested. This obviously doubles the shock of the grower caused by the demise of the palm.

I think the kill rate of so many palms being so high in europe suggests and entirely different situation.  We have bizzies all over in public plantings, the palmetto weevil kill rate appears to be low.  The kill rate being so high in europe suggests some other factor like the lack of predators for the RPW.  

[mlovecan]

I am surprised by the persistence of RPW in Spain and Italy.  At one time we had them everywhere but they almost exclusively attacked CIDP's, 

Nowadays, I rarely see them. Maybe twice this summer.

I haven't seen CIDP falling over for years either. Just yesterday, I passed by the location of one of the first ones to succumb to RPW on my part of the island. Three of that palms children now sit there quite happy. I was thinking how much better it all ended up compared to what I expected.

Edited December 18, 2019 by mlovecan

[Phoenikakias]

1 hour ago, mlovecan said:

I am surprised by the persistence of RPW in Spain and Italy.  At one time we had them everywhere but they almost exclusively attacked CIDP's, 

Nowadays, I rarely see them. Maybe twice this summer.

I haven't seen CIDP falling over for years either. Just yesterday, I passed by the location of one of the first ones to succumb to RPW on my part of the island. Three of that palms children now sit there quite happy. I was thinking how much better it all ended up compared to what I expected.

Lol you describe a surreal situation for Europe. Perhaps because of the isolation by sea that an island enjoys. Right this past summer three juvenile CIDP's fell victim to rpw only a couple hundred meters away fro my garden. In the attached picture you can see two of the three individuals having been affected. Now also the third individual is dead.

[mlovecan]

Yes. I guess we have been lucky. I noticed dead CIDP's up in Athens last time I was there and it wasn't clear how long they had been in that state.