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Nanoparticles, antibiotics new tools to fight plant problems

August 9, 2018

HAMDEN — Scientists at the Connecticut Agricultural Experiment Station are frantically trying to find ways to get plants to produce more fruit, vegetables and grain, and the newest screwdriver in their toolkit is a tiny one indeed.

Wade H. Elmer, chief scientist of the station’s Department of Plant Pathology, said that nanoparticles tiny enough to pass easily into plant tissues can be used to deliver minerals that make plants more resistant to disease.

“Copper, manganese and zinc are very important in protecting plant health,” he said Wednesday at the Experiment Station’s annual Plant Science Day. “But the problem is they don’t move freely within the plant — if you spray them on the leaves, they won’t move down to the roots.”

But when the elements are shaved down to the tiniest of particles, plants treated with them are able to move sprayed-on minerals from leaf to root.

To prove the hypotheses, he applied the nutrients in nanoparticle form to plots of eggplant — a crop that typically sees its yields drop by about 30 percent from a common soil fungus known as fusarium wilt.

Elmer said that the results were dramatic.

“The application costs about $15 to an acre and the increase in yield per acre — about 28 percent — was worth about $5,000.”

As for the safety of the treated eggplants, he said the mineral levels in the fruit from the treated plants were about the same as in the untreated plot.

“We eat them all the time,” he said, but added that more research will have to be done on the subject. “Our global food demands are projected to double by 2050, so we’re really up against it.”

About 800 people made the trek to the Experiment Station’s 108th annual Plant Science Day, from Girl Scouts looking for merit badges to landscapers, farmers and avid gardeners. It look place on Lockwood Farm, the Experiment Station’s 75-acre research facility.

The Experiment Station is conducting research on scores of plant diseases. One intensive area of research is on a scourge known as fire blight, a bacterial disease that has devastated apple and pear orchards the world over.

A fire blight-infected tree has leaves and branches that look like they encountered a propane torch.

“We see it from the U.S. to New Zealand,” said researcher Quan Zeng. “I visited an orchard in Litchfield County earlier this year which lost more than 200 trees. You expect the tree to produce for decades, and then the blight comes and the tree is gone.”

He said that the blight, caused by a bacterium named Erwinia amylovora, attacks the tree by entering through the blossoms. Then it moves into the twigs and branches, sometimes killing the tree after destroying the layers under the bark.

Zeng said that applying a broad-spectrum antibiotic such as streptomycin — better known as a disease-fighter in humans — can attack the bacterium.

Another strategy is to use other biological controls that “compete for nutrients and space” in the apple blossom. “Or they excrete anti-bacterial compounds,” he said.

“The problem with antibiotics is that the blight bacteria can become resistant to them,” said Zhouqui Cui, another scientist assigned to the fire blight problem. “The research is difficult because we only have a few weeks — while the blossoms are out — to apply the material.”

jburgeson@ctpost.com

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