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Fungus attacks, destroys part of Florida strawberry crop



ORLANDO, Fla., Jan. 24 (UPI) — A new strain of a deadly fungus has wiped out part of Florida’s strawberry crop this winter, causing perhaps millions of dollars in losses and raising fears of a new permanent pest.

First discovered in the Plant City area east of Tampa — the center of strawberry production in the state — the fungus took hold just as harvest season was beginning in December.

Consumers around the country felt the impact because Florida is the only place in the United States with a major winter crop.

The pestalotiopsis fungus invaded up to one-fourth of Florida’s 10,000 acres of strawberries and about half of its current organic strawberry acreage, said Natalia Peres, a plant pathologist with University of Florida’s agriculture research agency.

While hundreds of acres of plants were lost, other areas suffered partial losses of the fruit or were saved by fungicide spraying.

The actual financial impact is not yet available, but growers of the delicate specialty crop invest at least $15,000 per acre, according to state agriculture statistics.

The average retail price of organic strawberries spiked because of shortages to $6.23 per pound on Jan. 11 from $3.99 per pound during mid-December, according to the U.S. Department of Agriculture.

The fungus causes the fruit, leaves and roots to turn brown with rot, and farmers are worried that the disease might have settled permanently in Florida. They hope it won’t reappear, but the magnitude of infestation makes it more likely it will be a long-lasting problem.

“We lost maybe 80 acres of the organic. It’s definitely a setback, but it’s not a knockout punch for us,” said Gary Wishnatzki, a farmer in the Plant City area. “Conditions have improved, so we’re hopeful.”

At $15,000 per acre, that means Wishnatzki is dealing with a front-end loss of around $1.2 million.

His company, Wish Farms, grows about 600 acres of strawberries, 200 acres of which are organic, and he leases another 1,200 acres to other strawberry operations. According to University of Florida, an acre can yield about 32,000 pounds of organic strawberries, meaning Wishnatzi lost at least 2.5 million pounds of berries.

“We had warm and rainy weather for a few days in late December, and that allowed this new strain of fungus to flourish,” said Peres, a professor of plant pathology. “It arrived in Florida on a young plant brought in from a nursery.”

It hasn’t been determined where the fungus originated, she said. Since young plants generally are imported from California, North Carolina and Canada, Peres is working with researchers in those areas to identify the source.

Peres said she has been seeking a way to control the fungus, especially for organic farmers who have limited choices. She is testing how samples of the fungus react to various substances, including natural botanic-based fungicides that would be allowed in organic production.

Drier weather contained further spread of the fungus as of a few days ago, said Kenneth Parker, executive director of the Florida Strawberry Growers Association.

“It really was a perfect storm for these fungus spores to spread,” he said. “We were spraying and picking and moving through the wet fields for days, and that was spreading the spores.”

Besides finding a fungicide that works, Peres and the growers want to learn what other types of plants and trees might host the fungus.

“We can’t remove all plants from around our fields, but if we know the fungus can survive on oak trees, for example, removing some oaks might prevent having the fungus around another season,” Wishnatzki said.

Florida’s climate allows growing strawberries in winter, but also poses problems in terms of pests, mildew and fungus, Peres said. Because of that, little nursery production of strawberry plants exists locally.

Because of Florida’s problems with pests and fungus, organic strawberry production still is relatively small compared to conventional production. The new fungus proved to have significant resistance to both organic and conventional fungicides, Peres said.

As a small, specialty crop, strawberries often not covered by farm insurance policies. Wishnatzki said that level of risk is why organic produce is more expensive.

“We are working on it as quickly as we can to come up with answers, testing different products,” Peres said. “We’re trying to understand if this strain will survive here.”

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Clouds make newer climate models more realistic, but also less certain



June 24 (UPI) — Efforts to improve the precision with which climate models simulate cloud processes have yielded more realistic models. New research suggests these efforts have also introduced greater uncertainty, according to a study published Wednesday in the journal Science Advances.

When the latest generation of climate models started producing results last year, researchers noticed that several models were predicting higher amounts of warming than previous models. The results of the new models inspired news headlines that suggested global warming might be worse than previously thought.

As researchers with the Coupled Model Intercomparison Project, CMIP6, soon found out, a few of the latest generation of models predicted smaller levels of warming than previous models. To identify the cause of this uncertainty, CMIP6 researchers decided some historical context was needed.

One way to measure and compare the predictions of different climate models is by calculating the equilibrium climate sensitivity, or ECS.

“It’s kind of an abstract measure, but it’s one these metrics that has been around for a long time,” Gerald Meehl, a senior scientist at the National Center for Atmospheric Research, told UPI.

Essentially, scientists double the CO2 in a model and let the simulation run its course until the climate stabilizes. Each model — and each new generation of models — produces a narrow range of warming, between 1.5 to 4.5 degrees Celsius, or 2.7 to 8.1 degrees Fahrenheit.

“This kind of range has been out there for some time, and with each successive generation of models has produced about the same range in terms of degrees,” Meehl said. “With the latest generation of models, the average warming has stayed roughly the same, but the range has gotten bigger than ever — at both the low and the high end.”

When Meehl and his colleagues asked members of the groups responsible for the 39 new CMIP6 models why they thought the ECS value got bigger, most of them pointed to clouds.

To improve the accuracy of the latest generation of climate models, scientists have worked hard to simulate small-scale cloud processes. But these efforts have introduced a variety of new interactions between clouds and tiny particles called aerosols — interactions that can produce contradictory results.

“For example, if you have polluted air, particularly sulfur dioxide, that can influence clouds. Sulfur dioxide is emitted from cars and factories, and it goes into the air and forms sulfate aerosols,” Meehl said. “When you see the sky and it looks orange and hazy, chances are that a lot of that is caused by an abundance of sulfate aerosols.”

According to Meehl, these aerosols operate as cloud condensation nuclei. When these aerosols seed clouds, they seed clouds with a lot more tiny droplets.

“That increased number of small droplets makes the cloud brighter, and it’s going to reflect more sunlight and have a cooling effect,” Meehl said.

But this phenomena, now rendered more precisely in climate models, can also yield the opposite effect.

“On the other hand, you’ve formed all these droplets in the sky, but the aerosols absorb some sunlight, warm the air, and evaporate some of the droplets and that reduces the amount of clouds,” Meehl said. “That allows a little more sun into the system, and now you have a warming effect.”

Cloud-aerosol interactions are just one example of new simulated intricacies that offer both greater realism and greater uncertainty. According to Meehl, there are a variety of interacting processes involving a variety of different cloud types at different altitudes.

“With more interacting processes, your level of uncertainty can go up,” he said.

But ECS isn’t the only way to test and compare climate models. Most climate modelers prefer to use transient climate response, or TCR.

“You increase CO2 at 1 percent per year, compounded, until the time you double the amount of carbon dioxide, which is usually about 70 years,” Meehl said.

TCR works on a smaller timescale and works more like actual climate change. When scientists calculated the TCR range for the newest generation of climate models, they got the same average warming value but a smaller range.

Meehl and his colleagues shared the ECS and TCR values produced by the latest CMIP6 models in the new paper.

In addition to putting the latest generation of climate models into historical context, Meehl hopes the new study will inspire cloud modeling improvements.

“We’re doing a better job of simulating the clouds themselves, but now we have these different feedbacks that give you more uncertainty,” he said.

Now that researchers have highlighted this uncertainty, Meehl hopes climate research institutions and the climate modeling community will work to address the issue by directing more funds to relevant observational and analysis programs.

“You can’t simulate what you don’t understand,” Meehl said.

And to understand how exactly clouds will effect climate and vice versa, in the future, scientists need more robust observational programs and better satellite measurements.

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SpaceX launch Friday would boost Starlink network to nearly 600



Astronauts return to space from U.S. soil

NASA astronauts Doug Hurley (L) and Bob Behnken, who flew the Crew Dragon spacecraft to the International Space Station, brief mission controllers about their experience in the new vehicle on June 1. Photo courtesy of NASA

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Antarctic sea ice loss is good news for the continent’s penguins



June 25 (UPI) — While climate scientists worry about the loss of sea ice in Antarctica, penguins are flapping their flippers in applause. According to a new study, published this week in the journal Science Advances, many penguins prefer the Southern Ocean unfrozen — the less sea ice, the better.

Researchers had previously illuminated a link between sea ice extent in Antarctica and breeding success among Adelie penguin colonies, but a correlation doesn’t prove causation, and so scientists decided to investigate further.

To find out what might explain the positive impact of reduced sea ice coverage on breeding success, scientists strapped a trio of instruments to several dozen penguins. The combination of GPS trackers, accelerometers and video cameras helped scientists track how the movements and behaviors changed over the course of several years, as sea ice extents waxed and waned.

“What is new in this study is that we used a variety of electronic tags to record penguin foraging behavior in the greatest detail yet, and found mechanistic link among sea ice, foraging behavior, and breeding success,” lead researcher Yuuki Watanabe, scientist at the National Institute of Polar Research, told UPI in an email.

The novel data revealed the ways in which ice coverage in Antarctica affects the way penguins move across their environs and access food resources.

“In the ice-covered seasons, penguins traveled slowly by walking and needed to find cracks in the ice, where they dived repeatedly,” Watanabe said. “They were able to dive only through cracks, which also means that the competition among penguins was severe.”

The data also showed that, not surprisingly, penguins move much more efficiently in the water than on ice. Adelie penguins travel four times faster by swimming than by walking.

When sea extent was minimal, data showed the penguins were able to travel more easily, swimming and diving wherever they pleased.

“They came back to the nest quickly, which means that chicks waiting at the nest had food more often,” Watanabe said. “Overall, foraging conditions improved by the loss of sea ice, which directly linked to improved breeding success. Put very simply, penguins are happier with less sea ice because they swim.”

Less sea ice also allows more sunlight to enter the ocean, fueling larger krill blooms. Krill serve as the main source of food for Adelie penguins.

The latest findings don’t hold for all of Antarctica, and in future studies, researchers hope to explore the effects of sea ice extent on different penguin species living in different parts of the continent.

“The relationship between sea ice and penguin reproductive success is apparently different in maritime Antarctica (e.g. Antarctic Peninsula) where sea ice is normally sparse,” Watanabe said. “There, penguins look happier with more sea ice, but mechanics are unclear. I would like to conduct research in that region to understand the general patterns over the whole Antarctica.”

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