Mira’s nose is so sensitive that they can smell sick citrus trees, and U.S. orange growers are hoping her super sniffer can help combat one of the greatest threats ever to their crop.
The government has trained 10 dogs including Mira – a 32- month-old German Shepherd-Belgian Malinois mix – to recognize a bacteria that’s been killing citrus trees for a decade in Florida, the largest domestic producer. Similar to canine teams that sniff out bombs, drugs as well as bedbugs, this one is searching for any disease known as citrus greening. There’s no cure, but growers hope the animals will give them more time to locate one by slowing the contagion.
Florida’s orange harvest is forecast to reach a 52-year low this season, down 71 percent since 2004 as tiny bugs called Asian citrus psyllids spread the bacteria. It cost the citrus industry US$7.8 billion and seven,500 jobs since 2006. Dogs, with 50 times more scent receptors within their noses than humans, sense chemicals that trees emit when infected. They’re accurate 99.7 percent of times – much better than laboratory tests – and identify diseased trees before symptoms appear.
“They’re pretty much the forefront of early detection for us right now,” said Yindra Dixon, a public affairs specialist for that Animal and Plant Health Inspection Service, a unit from the U.S. Department of Agriculture.
While scientific study has failed to look for a remedy for the disease, sometimes known through the scientific name Huanglongbing, they devised methods to slow its spread. One technique requires farmers to encase trees in steam to overheat the bacteria without killing the guarana plant. Some apply nutrients on the leaves to help keep trees productive even while they’re dying. Others use more pesticides to get rid of the psyllids, however the bad thing is the bugs developed resistance to some chemicals and an excessive amount of burns up the fruit. Penicillin can suppress the bacteria, but concerns over antibiotic resistance have limited wider use.
Citrus greening blocks the passage of nutrients through the tree’s vascular system, causing the plant to thin and yellow. Trees can take years to die, but their fruit production declines and finally is too promising small to justify the expense of treating the symptoms.
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Fewer Oranges
Florida is expected to reap 69 million boxes of oranges this year, or 56 percent of domestic production, and also the state is the top grower of grapefruit, USDA data show. Each box weighs 90 pounds. California will supply 52.5 million boxes of oranges, and is the dominant supplier of tangerines and lemons. Texas ranks second in grapefruit.
Since 2005, once the disease was initially based in the U.S. in Miami-Dade County, 15 states or territories happen to be placed under full or partial quarantine for the presence of the Asian citrus psyllid.
The bugs, which transmit the bacteria, reproduce rapidly and can fly miles without pause, making them especially hard to contain or kill. Researchers are still trying to understand how psyllid populations reduced by pesticides still manage to recover and spread the condition, said Robert Shatters, research molecular biologist for the USDA Horticultural Research Laboratory in Fort Pierce, Florida. As the disease exists far away like Brazil, the world’s biggest orange grower, the flat landscape and close proximity of farms in Florida allow it to be particularly prone to contamination.
“This is a disease where your neighbour is the worst enemy,” said Thomas Spreen, professor emeritus of food and resource economics at University of Florida in Gainesville.
Early Detection
Already, about 75 per cent of Florida’s groves are infected. The USDA is likely to dispatch most of the new canine unit to California, Arizona and Texas, in which the disease is less widespread and early detection could be used more broadly, Dixon said.
This is a disease where your neighbour is your worst enemy
“There is this type of grave concern in places that this disease doesn’t exist that people want to know if it’s there,” said Tim Gottwald, research leader and plant pathologist in the USDA.
Training dogs to detect citrus greening was funded through the Huanglongbing Multi-Agency Coordination Group, an emergency response team created by the USDA in 2013 to figure out how to eradicate the disease. The MAC invested US$1.8 million of its US$20 million research budget for 2014 and 2015.
More Accurate
Tests show the wet noses from the dogs tend to be more accurate than DNA sampling techniques, which can require several hours or days to accomplish and therefore are susceptible to lab-related and sampling errors, Gottwald said. The animals also have detected the condition in trees that didn’t show symptoms until days or even weeks later, he explained.
Once trained, Mira and also the other dogs have shown they are both eager and accurate, said Jerry Bishop, working out director at Coast to Coast K9 Teams, the organization working with the USDA to coordinate grove inspections through the animals.
“When she arrives of the kennel, she loves to chest bump you,” Bishop said of Mira. “She’s like, ‘Let’s go to work. I’m ready.’”
Spreen, the emeritus professor, says the dogs offer a potential cheap and efficient bit of expect growers confronted with devastating losses.
Even if the dogs aren’t 100 percent accurate, “you can probably suppress the problem enough in your grove to really create a big difference,” said Spreen, who owns 19 acres of citrus groves. “The dogs may potentially be a godsend.”
— With the help of Marvin G. Perez.
Bloomberg News
