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huanglongbing disease

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Yorgos:

--- Quote from: a_Vivaldi on March 20, 2025, 07:22:11 PM ---Interesting, do cold weather events have a significant impact on ACP numbers? I had read a study at some point suggesting they could colonize as far north as zone 7 or 6 iirc, but this suggests that they probably can't, or at least not reliably or in great numbers.

--- End quote ---

My comment was based on ACP being a South Asian insect and thus cold sensitive.  Based on this article that may be a fond dream:
https://citrusindustry.net/2017/08/31/impact-of-temperature-on-psyllid-survival/

a_Vivaldi:

--- Quote ---Field observations and laboratory studies conducted by David Hall have shown that ACP can survive sub-zero temperatures as low as 21 F for several hours. While the air temperature in a grove may decrease into the low 20s for a short period of time during a freeze event, ACP may survive inside the tree canopy where temperatures are slightly warmer than the surrounding air temperature. In Florida, air temperatures are commonly measured in the grove via a standard thermometer mounted approximately 4 feet above the soil surface, which will be colder than inside the protected tree canopy.

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To me this is encouraging. While ACP might occasionally invade zone 7, 8a and northern parts of 8b , the typical winter should kill them or at least severely reduce the population. My understanding is HLB has a fairly low transmission rate, it takes a while for it to spread from tree to tree. So if the disease vector is only occasionally present, spread of the disease would be hampered. Add to that the fact that most wild and even cultivated citrus in zone 8 are to some extent resistant to HLB (wild trifoliate, cultivated trifoliate hybrids), and you decrease further the chances that whatever ACP do invade zones 7 or 8 will actually carry HLB.

Not saying I don't think HLB can't spread into zones 7 or the harsher parts of zone 8, just that to me it seems like the spread would be significantly slower and easier to control.

One thing I'm curious is, to what extent does feeding on trees with MaSAMP (the peptide in finger lime that can kill HLB bacteria) affect ACP? Are the ACP feeding on that tree ingesting and absorbing MaSAMP, and in high enough quantities to clear the HLB they might be carrying?

LBurford:

--- Quote from: Kalopa Guy on March 18, 2025, 09:56:51 AM ---Didn't think of that, I guess if you have uninfected plant mtl and keep it screened that would work. There is a millionaire in Kohala Estates who has a giant screened poly house with mangos inside. A few years ago I tried that with my cannabis it kept every thing out except the 2 spotted spider mite. Funny how $ solves many problems. Really sad how modern agriculture is increasingly moving indoors.

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The Chestnut blight came in on Chinese Chestnuts and killed billions of Chestnut and Chinquapin trees. One third of the forest east of the Mississippi River was wiped out. 

Galatians522:
I don't know about the finger lime, but I was just at a meeting where it was mentioned that curry leaf contains an antibacterial substance that kills HLB in the gut of psylids who feed on it. It is a favored host plant for ACP but the trees to not seem to suffer from HLB.

JakeFruit:

--- Quote from: Galatians522 on March 28, 2025, 07:26:12 PM ---I don't know about the finger lime, but I was just at a meeting where it was mentioned that curry leaf contains an antibacterial substance that kills HLB in the gut of psylids who feed on it. It is a favored host plant for ACP but the trees to not seem to suffer from HLB.

--- End quote ---
I have a bunch of curry leaf, never noticed any of those tiny critters on them. I have citrus inches/feet away that definitely get infested periodically. I haven't noticed any HLB yet, but that's probably just dumb luck or my inability to identify it.

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