help with Robellini

[sbg]

Hi.  I have a 3 trunk large Robellini.  About 3-4 weeks ago the stems and new growth started dying.

I just realized that I used lawn fertilizer instead of my old palm fertilizer (25-0-10) around it probably a few weeks prior.  Additionally, there was a 3 week period of no rain and sprinklers and I applied roundup near the palm to kill weeds/grass.  

I am worried about bud Rot.  in 2 of the trunks, there are a few green stems left but 99% are dead.  In the tallest, there are multiple green stems left.  I can't pull any of them out.

I have applied Copper Fungicide and drenched the crowns, and applied neem oil and crowns.  Also, before I realize I put lawn fertilizer I put some miracle grow out (last week).

I am also getting yellowing spikes with some lesions near the crown on older growth.

I am thinking I may have killed it with the wrong fertilizer, but hoping you have suggestions on what to do now to save this tree.

 

 

 

 

[Harry’s Palms]

I think watering the palm to try and leach out whatever it is that it doesn’t like. . If you used a granular fertilizer , try scraping up the top layer or soil around the palm and replace with garden soil. Harry

[Looking Glass]

You’re treating for crown rot, and I don’t think that one round of lawn fertilizer will do anything but speed it up.   Now that it’s hot, it just needs water.  Deep hand water it every day for a while.  Dont spray herbicides around it.  Time will tell, but the extra water will likely perk it up.  

[Merlyn]

I've not heard of neem oil being used as a phytophthora crown rot treatment.  Neem helps to prevent fungal spread but won't kill existing spores or fungus.  And it will burn new leaves if applied in the sun.  This is because the oil droplets act as a magnifying glass. 

The common treatments for crown rot are hydrogen peroxide (bubbles in the presence of fungus), Daconil (sticky surface fungicide), copper-based (good for the crown but use sparingly due to possible phytotoxicity), and Mancozeb (recommended to me by PTers, but I haven't tried it).  I'd squirt some regular household hydrogen peroxide in there and see if it bubbles up.  If so then it's definitely a crown fungus.  Follow up a couple of hours later with Daconil, and repeat 3x per week until it stops bubbling up.  The couple of green leaves in there are a good sign, it means there's still something alive in the crown.

[PalmatierMeg]

On 7/15/2024 at 12:59 PM, Merlyn said:

I've not heard of neem oil being used as a phytophthora crown rot treatment.  Neem helps to prevent fungal spread but won't kill existing spores or fungus.  And it will burn new leaves if applied in the sun.  This is because the oil droplets act as a magnifying glass. 

The common treatments for crown rot are hydrogen peroxide (bubbles in the presence of fungus), Daconil (sticky surface fungicide), copper-based (good for the crown but use sparingly due to possible phytotoxicity), and Mancozeb (recommended to me by PTers, but I haven't tried it).  I'd squirt some regular household hydrogen peroxide in there and see if it bubbles up. If so then it's definitely a crown fungus.  Follow up a couple of hours later with Daconil, and repeat 3x per week until it stops bubbling up.  The couple of green leaves in there are a good sign, it means there's still something alive in the crown.

This. I unintentionally killed a bunch of Dypsis pembana seedlings some years back that I was trying to sell at a yard sale when the sun fried them after I treated them with neem oil. Didn't sell a single one. Won't do that again. If you must use neem oil keep the palms in deep shade until the fronds are clear of it - be paranoid around any palm treatment if the word "oil" appears on the bottle.. If you sprayed those pygmies with the stuff in the sun you may have roasted greens for dinner. Good thing roebeleniis are common and cheap.

[SeanK]

Neem is popular for scale as it coats the buggers and suffocates them.

[sbg]

Thanks everyone for the feedback

I am going to keep it watered, but hopefully not over -watered.  Thanks for the comments on neem oil.  Next up will try the peroxide and daconil and hope for the best.

[Merlyn]

3 hours ago, SeanK said:

Neem is popular for scale as it coats the buggers and suffocates them.

I tried it on some heavily infested sagos, and it did nothing but burn the leaves in the sun the next day.  The sago died, the scale did not.  It may work better on soft scale, but seemed useless on the armored cycas scale.  Plus if you miss one...next week 1000 more hatch.  A systemic like Dinotefuran is the only thing that has worked for the ~75 Cycas in my yard.  Even that isn't 100% effective and sometimes comes back a few months later.

[SeanK]

13 hours ago, Merlyn said:

I tried it on some heavily infested sagos, and it did nothing but burn the leaves in the sun the next day.  The sago died, the scale did not.  It may work better on soft scale, but seemed useless on the armored cycas scale.  Plus if you miss one...next week 1000 more hatch.  A systemic like Dinotefuran is the only thing that has worked for the ~75 Cycas in my yard.  Even that isn't 100% effective and sometimes comes back a few months later.

Thanks for responding. I am fighting scale on S.minor, using a topical insecticide. May be time for a systemic.