Lethal Yellowing in Conservatory

[hbernstein]

Has anyone ever heard of lethal yellowing appearing in a conservatory or greenhouse palm being grown outside of an area where LY occurs?

We have two large Howea fosteriana that are not growing near each other, but are in the same conservatory. They are both experiencing very rapid decline, even though their horticultural environment has remained stable for many years.

Our IPM specialist suspects LY, but I'm not convinced. The appearance just doesn't seem quite like LY to me, and the decline to near death has visibly ocurred in one of the palms within two weeks. That's too fast, even for LY.

[Kim]

What was the source of the palms, and how long have they been in the conservatory? What is the temperature where the palms are grown?

[hbernstein]

One of the palms has been in the conservatory for more than 50 years. The other for more than 15.

Temperatures range in Winter between mid-fifties for lows to low seventies for daily highs. Typical Summer temperatures are high sixties to mid-eighties.

[Moose]

I would suspect some kind of fungus or contagion other than Lethal Yellowing. I come from an area where LY has been established for quite some time. Usually LY is introduced by an insect vector - here its mindus crudis (sic). Without observing your palms and given your location, another malady has a greater probability to be your culprit in my opinion.

[Zeeth]

I agree with Moose. LY is carried by a tropical insect that would have to be introduced to the conservatory. Unless you recently had a sod shipment from South Florida then it's highly unlikely. Pictures would probably help quite a bit.

[hbernstein]

I would suspect some kind of fungus or contagion other than Lethal Yellowing. I come from an area where LY has been established for quite some time. Usually LY is introduced by an insect vector - here its mindus crudis (sic). Without observing your palms and given your location, another malady has a greater probability to be your culprit in my opinion.

I agree with Moose. LY is carried by a tropical insect that would have to be introduced to the conservatory. Unless you recently had a sod shipment from South Florida then it's highly unlikely. Pictures would probably help quite a bit.

Those are my thoughts, as well. I think that it's highly unlikely that the insect vector could establish itself. It's also interesting that only the Howeas are sick. We grow several other palm species that are highly susceptible to LY but are unaffected.

Does anyone know of a pathogen that favors Howea over other palms? I don't.

[Moose]

Do the plant caretakers sterilize their cutting tools between plants? Do they cut green stems & petioles ?

[hbernstein]

Do the plant caretakers sterilize their cutting tools between plants? Do they cut green stems & petioles ?

Unfortunately, they don't. The horticultural practices aren't the best.

These aren't plants that have had anything green trimmed from them in a long time.

I'll try to post some pictures tomorrow.

[MattyB]

I know pink rot (gliocladium blight) can take out a Howea very quickly here in SoCal.

[Keith N Tampa (ex SoJax)]

Phytophthora root rot kills like lightning when its happy.