Hi all,
I just wanted to chime in a little bit here on the HLB/ACP discussion.
I just got back from a week long International Research Conference on HLB that took place in Orlando, Fl.
http://www.doacs.state.fl.us/pi/hlb_conference/overview.html
First off to answer Susan's question:
"How far is Four Winds Nursery from San Diego County?"
We are about 500 miles north of San Diego.
As much as we would like to believe that this distance will by us time, the reality is that it may not. ( I will explain)
The conference was pretty amazing, as researchers from around the world presented the latest work on HLB. The HLB problem is the biggest thing going in the citrus research world and the amount of money and minds working on this problem is rather impressive. I would advise anyone interested to look over the proceedings for themselves, there is a lot of information there.
Ill just mention a few highlights and if anyone wants to chat more, I would be more than happy to do so.
HLB is a bacterial disease (Candidatus Liberibacter). As you all know it eventually kills trees and makes the fruit useless (the flavor becomes bitter). One big problem is that, so far they have been unable to culture the bacteria. The other problem is that it takes 3-5 years for symptoms to express themselves in the trees.
Without strict controls on the movement of citrus and other related host plants, the bacteria and its vector (the Asian Citrus Psyllid) can move rapidly. Take the Florida situation for example: The psyllid was first discovered in southern Florida in 1998. By 2000 it was state wide, moved largely through retail nurseries traveling on Murrya Paniculata (Orange Jasmine) which was unregulated. In 2005 the disease was first discovered in the Miami area. It is believed that the original source of HLB trees was one farmer who illegally imported infected budwood from Taiwan. By the end of 2006 HLB had been detected in 26 counties and it can currently be found in 32 counties in Florida. That is the really scary part; all it took was one illegal importation to unleash the disease! This is also why our (Four Winds Growers) geographic distance from San Diego may not leave us completely at risk. It is widely assumed that there are already HLB infected trees present in California (most likely in someones back yard) and it is only a matter of time before the psyllid finds it.
There has been quite a bit of research that is trying to identify any possible resistant citrus varieties, but the disease does not discriminate and to date none have been identified. I remember Joe Real had expressed hope about macroptera, but it too has been found to be susceptible to HLB. There is also considerable debate as to whether or not HLB is seed transmissible. At this point it remains unclear, it looks like yes but the disease is weak in seedlings and more study is required before they will know for sure.
There was some positive information about the use of guavas to discourage the psyllid form entering citrus groves. They have isolated the chemical responsible and are in the process of synthesizing it and trialing it in the field. However, guavas alone will not protect citrus. The only thing that works is chemicals and screen houses.
The major take home is that to be successful in limiting the spread of ACP and HLB the regulations have to stay in front of it. If the rules are simply reacting to the movement of the psyllid it can easily be too late to stop the spread. At this point it is unclear what will happen in California, but rest assured there will be a day where nurseries will no longer be able to sell trees not grown under insect proof screen. When this becomes law, many nurseries will likely go out of business because of the capital required to build screen structures. In Florida, half of the citrus nurseries went out of business and the cost of trees doubled over night.
I know that the rules prohibiting the movement of citrus budwood from once place to another can seem like a pain and that the temptation to get your hands on something new can be great, but the consequences of this type of action can be great. Another interesting observation was that in Sao Palo state in Brazil, it is mandatory to remove trees infected with HLB. This mandatory removal has helped to slow the spread of the disease, to date 2.4 Million trees have been pulled! In Florida, tree removal is encouraged but not mandatory, which is the same situation for back yard trees. As a result, the disease continues to spread. It is believed that there are at least 100,000 acres of abandoned groves in Florida at this time. Those groves plus the back yard trees are protected by our private property rights as Americans, but it seems clear that more restrictive measures might be more effective.
Many growers in Florida have stopped replanting trees because they do not believe they will ever reach maturity and provide return on the investment. Within 5 years citrus could become a rotational crop in Florida.
Well see what happens, but the future for citrus production worldwide doesnt look good right now. Hopefully the science will catch up and there will be some major breakthroughs in the next few years.
Sorry for the long post, but this situation is serious and it is important for everyone to know the latest.
