Posts Tagged: citrus greening disease
Deadly Citrus Greening Disease: A Better Lure for Asian Citrus Psyllids
If you like or grow citrus, you ought to be worried about the worldwide threat of the deadly citrus...
UC Davis chemical ecologist Walter Leal (center) examines a lure in Mogi Mirin, São Paulo on Brazil’s Independence Day (Sept. 7) with Haroldo Volpe (far right) and Renato de Freitas, both of Fundecitrus.
Targeting the Asian Citrus Psyllid
A major citrus pest may experience a “Bah, Humbug!” kind of year. If all goes as...
The Asian Citrus Psyllid Team: Scientists in the front row (from left) are Tatiana Mulinari, Rodrigo Magnani, Antonio Juliano Ayres, Walter Leal, Marcelo Miranda, Victoria Esperanca, Odimar Zanardi, and Rejane Luvizotto. The three scientists in back are Haroldo X. L. Volpe (white shirt) Renato de Freitas and Rômulo Carvalho.
Resistant Citrus Selections to HLB?
Three citrus trees that produce inedible fruit at the UC Lindcove Research and Extension Center in Visalia may be a game-changer for the citrus industry, reported Ezra David Romero on Valley Public Radio.
The trees are thought to be resistant to huanglongbing, a severe disease of citrus that has devastated the Florida industry and could become a serious problem in California. The citrus-saving potential of the three 34-year-old trees was outlined in an article by UC Agriculture and Natural Resources writer Hazel White in the most recent issue of California Agriculture journal.
UC Riverside citrus breeder Mikeal Roose collected seed from the trees and will test seedlings as soon as they are large enough.
"So what (breeders) have to do is cross this with some edible varieties and eventually create something that has the gene for resistance, but also the genes for good fruit," said Beth Grafton-Cardwell, Lindcove director and research entomologist.
Huanglongbing disease has cut citrus production in Florida by more than half. It's been found in residential citrus trees in Southern California, but hasn't reached the state's vast commercial orchards yet. Grafton-Cardwell said she expects the disease will arrive in 4 or 5 years.
Yeah!!!!
HLB resistant variety
Electronic “sniffer” for determining HLB
At a recent conference on Postharvest Technology Advances, Cristina Davis from the UC Davis Department of Mechanical and Aerospace Engineering presented information on the development of a device that can smell out trees infected with Huanglongbing (HLB).
Scientists at UC Davis are refining a mobile chemical sensor that can detect diseased citrus trees by sniffing their volatile organic compounds (VOCs). VOCs are emitted by all types of plants and contribute to their distinctive odors—such as the perfume of orange blossoms and pungent scent of garlic in the air. VOCs must exist at very high levels for humans to smell them, and there are some VOCs people cannot smell at all. The machine is able to figure out the signature smells of HLB infected trees, sort of the way people evaluate wines with terms like “grassy”, “plum”, or “austere”, and distinguish them from healthy or trees infected by other diseases.
Finding HLB-infected trees and eliminating them before Asian Citrus Psyllid (ACP) picks up the disease and spreads it to neighboring trees is a major challenge. The pathogen in the tree cannot be detected by leaf testing for three to nine months after infection, and the symptoms don’t show up in the tree for a year or more after infection. Meanwhile, the disease can be spread by ACP. Research is under way to develop early HLB detection so that infected trees can be rapidly removed. Early detection will also allow researchers to more rapidly assess treatment programs for controlling not only the spread of the disease, but also possible cures or rootstocks or scion varieties that might have some resistance to the disease.
HLB infected tree showing mottling in one part of the canopy
HLB backyard
HLB citrus
USDA to provide $11 million for citrus greening research
The USDA will provide $11 million for scientific research to battle citrus greening disease, according to a USDA news release issued this morning. Citrus greening disease is spread by the Asian citrus psyllid, which made its way to California in 2008. When a tree acquires the disease from the pest, nutrient flow is obstructed, the fruit stays green, grows lopsided and tastes bitter.
USDA will invest $2 million this year for research at the U.S. Horticultural Research Laboratory in Ft. Pierce, Fla. The remaining $9 million will be offered in a three-year competitive grants program by the agency's National Institute of Food and Agriculture.
The news release said USDA will also establish a Citrus Disease Research and Development Advisory Committee with representatives from the grower and scientific communities. The advisory committee, which reports to U.S. agriculture secretary Tom Vilsack, will provide leadership to citrus disease scientists.
Citrus greening is one of the most devastating diseases affecting any commercial agricultural crop, according to the National Academy of Sciences. More than 250,000 jobs representing key sectors of the U.S. economy are at risk, including harvesting, packaging, processing, transportation, marketing, retail sales, and nursery production.
Citrus greening threatens to destroy over 1 million commercial citrus acres that have an annual production value of approximately $3 billion across the nation. Yearly losses could reach $10 billion if citrus greening is left unchecked.
Asian citrus psyllid was first detected in California in San Diego and Imperial counties. The pest is believed to have been introduced from northern Mexico. Adult psyllids have also been trapped in Orange, Los Angeles and Ventura counties. The University of California, California Department of Food and Agriculture, USDA and the citrus industry are working closely to quarantine the affected areas and try to eradicate the pest.
The state of Florida first detected the Asian citrus psyllid in 1998 and citrus greening disease seven years later. The pest and disease have been detected in all 30 of Florida's citrus producing counties and in Louisiana, Georgia and South Carolina. The states of Texas, Mississippi and Alabama, like California, have detected the pest but not the disease.
Red pins on the Texas Department of Agriculture map show where citrus greening disease has been found. Yellow pins show where Asian citrus psyllid has been found.