California: Citrus Trees Threatened by Greening Disease


B. McPherson

 

California is the latest state to be hit with the invasive fly that carries what is called Greening Disease. It was first identified in March of 2012 and has citrus growers on high alert. The culprit spreading the disease is a tiny flying insect, a psyllid fly. It has established itself in Florida where it was discovered in the citrus groves in 1998. Now California is fighting the difficult battle against this unwelcome pest from Asia.

The fly damages the citrus tree in two ways. It sucks juices from the new growth, leading to stunted and deformed growth. More seriously, it carries a bacterium that causes the greening disease. There is no treatment and no cure. Citrus trees must be cut down and destroyed to slow the spread of the disease. Once they are infected with Candidatus liberbacter, they are doomed in any case. Once infected any fruit produced is deformed, small and has a bad taste.

Humans have aided the spread of the disease as well. The 1998 infestation was discovered originating in commercial nursery plants. As well, Texas has sourced the pest to nursery stock. Transferring grafts from an infected tree to a non-infected one will also spread the disease. 

Florida orchardists have used pesticides to prevent infection of their trees. A systemic poison, Admire(imidacloprid) is used. Also neonicotinoids and pyrethroids may be applied. Florida has imported and released two parasitic wasps to try to control the flies. Ladybugs have proved to be voracious eaters of the insects as well.

This multi-million dollar invasive species has spread around much of the tropical and sub-tropical fruit growing areas. Australia and the Mediterranean are the only citrus growing areas without it.

Next time you return from an overseas trip and are asked to declare plant or animals material that you might be bringing with you, cooperate and tell the truth. The cost to growers and ranchers from introduced pests is enormous. If you don’t care about the producers, big or small, think about your own pocketbook. If California and Florida lose many of their citrus trees to this latest invader, your food bill will be greater.

For detailed information on the psyllid fly, the Universityof California has an excellent page.

Other names for Greening Disease: Huanglonglbing, yellow dragon disease

Comments

Post a Comment

Popular posts from this blog

Prince Rupert Says No to Enbridge Pipeline

Image
B. McPherson Prince Rupert city council joined a growing list of BC coastal communities that are saying “No” to the Enbridge proposal to build a twinned pipeline from Edmonton to the coast. The decision of the Prince Rupert city politicians was unanimous. Already the village of Kitimaat, Terrace and the Skeena Queen Charlottes Regional District have voiced their opposition to the project. There are ongoing hearings by a federal court appointed Joint Review Panel which are gathering input from interested parties about the proposed Enbridge Northern Gateway Pipeline which would bring crude petroleum from the oil sands of Alberta to the coast of British Columbia. The proposal would see a twinned pipeline run over the Rocky Mountains and through wilderness to the treacherous west coast. The proposed terminus at Kitimat would require tankers to wend their way through the maze of islands and reefs to load up at the head of Douglas Channel. While the hearings and the finding
Read more

Abandoned Oil Pipelines What Lurks Below?

Image
These photos were taken July 2012 in the historic Turner Valley, Alberta B. McPherson Controversy over new oil pipelines is reaching boiling point in many circles. Heated debate is taking place over the proposed Enbridge Northern Gateway and Keystone Pipeline proposals. Safety, disruption to landowners  and more are being weighed against the money to be made transporting and selling petroleum products. It got me thinking about the old pipelines. What happens to a pipeline when it is too old to use or not needed? It’s a bit of an Alice in Wonderland scene. The US laws and regulations are different from ours in Canada. The Pipeline and Gas Journal is a source of information about abandoned pipelines in Texas. Apparently a pipeline in Texas may be abandoned by a company, but it still retains ownership and may choose to reactivate the line at a later date. In the meantime, the right of way or easement is no longer maintained, but the through which the pipe extends is not free
Read more

Efficient Rail Transport May Make Pipelines Obsolete

Image
B. McPherson What happens to all the abandoned pipelines? Oil pipelines have huge direct costs to build, but they also have many hidden costs. In spite of dire warnings by environmentalist the world is demanding ever greater supplies of the black gold. For those countries that have it and market it successfully, money comes rolling in. But at what cost? An oil pipeline is a hugely complex thing. Enbridge Corp. has been battling citizens in British Columbia over its proposed Northern Gateway Pipeline and the Keystone Pipeline in the US has been stalled for months. When Big Oil needs to transport oil or bitumen to refineries, it usually gets a smooth ride to approval. Labelling energy security as a national priority, property rights are infringed upon. People in Canada cannot legally stop the installation of a pipeline across their property. The high pressure conduit is often buried only a few feet below the surface leaving crops, buildings and livestock vulnerable to a
Read more