serge, it would be highly unlikely the ACP found in San Jose would be infected with HLB. What you're simply seeing is the inevitable march northward of ACP, which has been in the state of California now, for over 10 years. There has been zero reported evidence of infected ACP in our state. But, we all know it's just a matter of time. We are hoping for a race to the cure before that happens.

If you're in a quarantined area of California, do not move your trees around, do not share scionwood (do not share scionwood in ANY EVENT, order clean budwood from the CCPP), do not go into quarantined areas to buy citrus trees, and transport them back to your home.

Spraying the tree will help, but not the trunk. ACP alights on the foliage, not the trunk of a tree. Eggs are laid underneath the leaves. Spraying a tree you buy, prior to taking it home is probably a good idea if you're in a quarantined area, frankly. Even though trees are treated and inspected, time marches on, and an ACP could land on the tree and not have yet attempted to feed on the treated tree. Nearly all commercial trees in the state of California are treated with a commercial grade systemic Imidacloprid, as well as other systemic insecticides, so chances are low that you'd get a live ACP hitchhiking home with you, but for us in California, you just cannot be too safe.

And, a link to the most promising treatment, yet, for HLB. This would be a treatment any of us hobbyist growers could apply to our EXISTING trees. Most of the other promising research has revolved around the development of resistant/immune cultivars. But, that doesn't do us any good with our existing trees. I am very hopeful that this treatment will continue to prove to be effective, and will soon be available to everyone. I posted this back in June, and to the Citrus Growers Forum as well.

Patty S.

Here is a link that might be useful: Gout Treatment a Possible Cure for Citrus Greening

Hi Patty. I think there's been one HLB infection in California. They think that, since there's a 3 year incubation period, that there are probably other trees infected as well. I hope they're wrong! I am very hopeful that a treatment can be found to protect our home orchards (and the commercials ones too, of course). I also posted about the gout treatment in June :) http://forums.gardenweb.com/forums/load/citrus/msg0609554010504.html?1

Here is a link that might be useful: HLB case in CA

I agree with Serge that this is very bad news. This Asian citrus psyllid find is nowhere near the previous range of the ACP. There is no way that ACPs flew that far on their own. It is clearly the result of human movement of either a nursery tree from an infested area or from the movement of infested fruit/leaves.

The treatment of the nursery trees before they are shipped only lasts a couple of months and then the trees are vulnerable to infestation by ACP. At one point the CDFA had more than 20 people trying to keep ACPs out of citrus nursery trees in Southern California; they were fired due to funding cuts. I live near San Jose and took a look at the neighborhood myself. I visited a nearby nursery with trees clearly vulnerable to ACP infestation -- there were some already infested with CLM. One of the production nurseries puts dates on the trees and there were some for sale that had been sitting around for more than a year.

I recently joined some citrus farmers on a field trip to see Asian citrus psyllids in the field. They are quite hard to detect. I took some photos that show how small they are. My writeup with photos can be found here:
Asian Citrus Psyllids: Elusive but Spreading

The San Jose ACPs did test negative for HLB, but the neighborhood where they were found is actually at high risk for HLB. For those interested in understanding how risk for HLB is assessed, a great presentation can be found here:
Risk-Based Residential HLB/ACP Survey for California, Texas, and Arizona

It seems that a new treatment ends up in the news at least every couple of weeks. Florida is nearing 100% infection and experimental treatments like these may be appropriate there. In California the top priority is to stop HLB from spreading. Any HLB positive trees must be detected quickly and immediately removed.

Best regards,
Dan Willey

Serge, there has been one instance of HLB discovered, but this was NOT caused from an infected ACP here in California. The discovery was of an infected grafted branch of pummelo budwood in LA county. A person in the Asian community who had smuggled infected budwood in from Asia, grafted it to a neighbor's tree. A perfect example of why you should never use anything but clean budwood from CCPP. This is very, very different than a tree that has been infected by a ACP carrying HLB. There have been zero instances of further infection in that area OR of infected trapped psyllids anywhere in the state of California. So, everyone is hoping and praying that there were no psyllids in that area while this infected branch was growing on this tree. That area is continuing to be monitored very closely.

And, where I live is probably one of the highest risk areas of California - San Diego county. Right on the border of Mexico. Fruits and plants get smuggled across the border all the time, despite border checks.

This is why I treat my trees twice a year with Imidacloprid. I am next to a 147 acre abandoned orange orchard that is not being managed. Supposedly they are monitoring the orchard, but when I called the ag agent, found out they only had traps set in the very most NE corner of the orchard. I reside up against the very SW corner. A lot of unmonitored trees between me and the traps :-(

In listening to some of the foremost experts on HLB, most likely it will occur in someone's backyard. Most all California commercial citrus growers are closely monitoring their groves, and have been treating their trees for some time, now. It is the hobbyist grower who is at risk.

Again, there is no HLB in California that we are aware of, so the top priority at this point is to monitor the continued discovery of the ACP as it spreads through our state, and watch those areas very closely. We are trying very hard to beat the clock here in California - find a viable treatment before we discover HLB.

The latest and most promising HLB treatment is in a link, below. I will be very interested to see how this does out in orchards. I'm interested because this is a way us hobbyists could also treat our trees, and the price would not be unreasonable.

Lastly, Dan, you are correct. The federal government just coughed up more monies to put towards HLB research, so we are seeing more an more studies being conducted. I am hopeful we will have some viable alternatives appearing in the next year or two.

Patty S.

Here is a link that might be useful: UF team finds possible treatment for citrus greening

HLB is a little like AIDS... it is sorta "hard" to get it. You have to have the ACP (Diaphorina citrii); and you have to have the bacteria.
Last week I discovered the ACP at one of my farms in the South coast of Guatemala; but luckily in that area we do not have the bacteria. The other saving factor ... for me... is that any ACP that sucks on my Meyer lemon leaves, dies.
There is no chance of further infestation. It is because we treat our trees 3 times per year with Imidacloprid.

Actually citrus greening in Los Angeles was first found in an infected Asian citrus psyllid. Hacienda Heights had an infestation and psyllids were being tested; that is how they found the tree. You can read about it in my article on pummelos:
Pummelos

One big problem is that the currently used "gold standard" test to detect citrus greening in a tree does not detect it until long after the tree has been infected and meanwhile the psyllids have been spreading the disease. If AIDS is your preferred analogy for HLB, you can consider the psyllid as a flying hypodermic needle. If the psyllid feeds from an infected tree and then feeds on an uninfected tree, then there is a new infected tree.

Scientists working on improved tests for HLB that would detect it in trees sooner have already found some "presumed positive" trees in the quarantine zone where the infected pummelo tree was found. Although those trees did not test positive by the "gold standard" test, there was enough concern that "presumed positive" trees were removed.

The resources devoted to the trapping and testing of psyllids are limited and being further stretched as the psyllids spread; there is concern among scientists that the reason that no further HLB positive psyllids have been found in California is because there has not been enough trapping and testing and not because they are not out there.

Treatments for HLB may be useful in Florida, but in California the situation is quite different. Any HLB positive trees must be removed as soon as they are detected or the disease will spread.

Best regards,
Dan Willey

You're correct, Dan, I forgot they trapped some infected psyllids, which led them to the infected pummelo graft.

And yes, the testing for trees allows an infected tree to stay in production much too long, allowing psyllids to spread the disease for a significant amount of time prior to finding an infected tree, and removing it. Damage is long done. This was part of Florida's issues in attempting to control the spread of HLB. Newer, swifter tests are being developed that have a high degree of accuracy, but of course, they are more expensive.

And there are not nearly enough traps out there, or manpower available to manage the amount of traps we need in urban areas, to monitor the psyllid population. In listening to Dr. Allan Dodds, Professor Emeritus from UCR (whose graduate students, such as Dr. Erik Mirkov at Texas A&M) are leading the research in the fight agains HLB said that HLB will start in someone's back yard. Since about 70-90% of homes in S. California have at least 1 citrus tree, it is simply logistically impossible to monitor all the backyard citrus. One of the comments Dr. Dodds shared with us at our CRFG meeting, was the possibility of requiring the removal of ALL backyard citrus, if HLB is found in the state (as in spreading - not an isolated case as found in Hacienda Heights). That produced a rather loud collective gasp in our packed meeting. Considering many of our members, such as myself, have more than 50 trees (in my case, over 100) on our properties, that was simply an unacceptable solution, in order to protect our commercial citrus industry. And Dr. Dodds also proposed to us, that HLB very well may be here, but due to the situations you've mentioned - not enough monitoring capabilities - we may not discover it until it has really taken hold somewhere.

So, California commercial growers are being much more preemptive, than the commercial growers were in Florida. Trying to learn from the disaster in Florida - they are treating their trees well, completely and thoroughly. They have been for several years, now. Much prior to HLB being identified here in our state in the hopes they can keep HLB out of our commercial citrus orchards. Hoping that they can stave off massive infection prior to successful treatments being made available.

There are no "useful treatments" in Florida for HLB. Commercial growers are simply replanting every 5 years, a ridiculous and costly option. Some growers are attempting to flood their orchards with nutrients to make their trees as healthy and vigorous as possible, which really only slows the inevitable. But, might buy a grower another year of production, thus lowering their overhead. A few have tried super heating their trees, but that treatment is simply not practical in the large sense. It's much, much too late to remove trees - Florida became overwhelmed before this could have ever have been considered an option. They got caught with their pants down around their ankles, sadly. And, they are paying an indescribable cost for their lack of vigilance and concern. California will not be caught off guard, but for now, there is nothing much we can do, except treat all our trees on a regular basis, and hope for a cure, soon. Otherwise, our alternative may be horrific - the prophylactic removal of all backyard citrus trees.

Patty S.

Here is a link that might be useful: CDFA Press Release: HLB Discovered in Hacienda Heights

At least California has the knowledge and more important the political will to actually implement a program; imagine what we face in Guatemala. As history is a guide, California actually went door to door and systematically destroyed the Meyer lemons in the 50's when they discovered them to be silent carriers of Tristeza. Thank God the founder of Four Winds, together with the Univ. of Calif Davis found a cultivar free of that; and in 1975 released it to the public as Improved Meyer Lemon.
HLB destroyed almost 80% of Florida citrus before they began seriously to deal with it; 65 % of Cuban citrus before the same actions were taken; 40-50% of Mexican citrus; and 30-40% of Brazilian/Uruguayan citrus.
Harsh as it may seem to destroy all backyard citrus in California, be thankful you live in a place that at least has the possibility of such action.

Yes, they sure did that, John. And, Dr. Dodds stated that the commercial citrus industry has enough clout (they generate a significant amount of revenue and provide an awful lot of jobs for folks here in the state of California), that the CDFA and USDA would be willing to do just that - cut down any and all backyard citrus in order to save the commercial groves. It is horrifying to think, but there is just so much at stake, here, and after watching the commercial citrus industry in Florida go right into the toilet, California is trying to learn some valuable lessons. I keep my fingers crossed for you, and for all of us hobbyist growers. It is really a very scary thing.

Patty S.

EXETER, CA detection.

Here is a link that might be useful: news story

This post was edited by serge94501 on Thu, Nov 6, 14 at 12:09