Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

News stories

Why 'AA' is for Avocado Addict

Avocado addicts know the avocado as a veritable green goddess that never disappoints, never deceives, never dissatisfies. (Photo by Kathy Keatley Garvey)

If you're like most of us, you “go bananas” for a banana for breakfast.

It's healthy, nutritious and packed with potassium.

But wait! You should probably go bananas for another fruit--that pear-shaped avocado. Did you know the avocado provides more potassium than a banana?

It does. A medium-sized banana yields 422 milligrams of potassium, while a medium-sized avocado, a whopping 708 milligrams.

Dietitian Linda W. Adams
Dietitian Linda W. Adams of UC Davis Occupational Health Services (among her responsibilities: teaching a 52-week UC Davis Diabetes Prevention Program) says “I think my favorite part about avocados, in addition to their wonderful flavor, is that they are full of monounsaturated, heart-healthy fat AND have more potassium than bananas! These two nutrients are lacking in many Americans' diets.”

“Eating more unsaturated fats -- as opposed to saturated fats and processed carbohydrate -- is a delicious step we all can take to maximize cardiovascular health,” Adams says. “Avocados are such a delicious way to do that!"

We love our avocados, our veritable green goddess that never disappoints, never deceives, never dissatisfies, whether we “butter” them on toast in the morning for breakfast, or slice or chunk or cube them for our salads at lunch and dinner. Health-conscious folks call them a superfood, and even mash and freeze them to ensure a steady supply in the winter. There's even a website on “50 Things to Love About Fresh Avocados.” 

This year, California's 2000 avocado growers anticipate a yield of 374.6 million pounds. That crop forecast, according to Tom Bellamore, president of the California Avocado Commission, is nearly double the yield of the 2017 crop and “despite the ravages of Mother Nature in California's avocado growing regions.”

UC Cooperative Extension adviser and avocado researcher Ben Faber of Ventura and Santa Barbara counties, points out that the avocado is really a fruit, not a vegetable. “The Supreme Court classified the tomato in 1920 or so as a vegetable because that's the way people think of it and it was taxed differently for tariffs. Politics or botany separates a lot of things in our lives.”

“The avocado is an amazing fruit,” Faber says. “It grows on a tree and comes to maturity, reaches certain oil content and a stage at which it will ripen, but it does not ripen on the tree. It needs to be removed from the tree before it will soften. If the fruit is removed before it has reached maturity it will not soften, and will remain rubbery and inedible.”

“One of the problems is that the fruit will hang on the tree for an extended period of time and it is hard to know when they are mature,” Faber points out. “Avocados are not like apricots where you have about two weeks to get the fruit off before it falls off. As the fruit stays on the tree, it gradually develops more and more oil content and has a richer flavor.”

What if the fruit stays on the tree too long? “It can develop an almost rancid flavor,” Faber says. “So it is good to know when the best, acceptable flavor is. Avocado varieties fall into general seasonal periods when they are mature, such as ‘Fuerte' and ‘Bacon' in winter, ‘Hass' in spring/summer, ‘Lamb-Hass' in summer/fall.”

An avocado must be removed from the tree before it will soften, says UC Cooperative Extension advisor Ben Faber. (UC ANR Photo)
We've all had our share of rock-hard avocados that seem as if they will never ripen. Sometimes they're as hard as the pits within! “Given time, they all soften,” Faber says. “But they all don't soften evenly, which is a reflection of their maturity or how they were handled in the food chain, stored at the wrong temperature or with too many bananas.”

The fruit will typically be ripe in seven to ten days, Faber advises. “If you want to speed things along a bit you can take three or four avocados and place them in a loosely closed paper bag with two or three Red or Golden Delicious apples or ripe kiwifruit. The purpose of the apples or kiwifruit is that these fruit produce a natural plant hormone, ethylene, that will help stimulate the avocado to produce its own ethylene. Apples and kiwifruit are known to produce lots of ethylene. The Delicious apples are varieties that produce more ethylene than other apple varieties. You can keep them even after they are shriveled and they will be producing ethylene.”

Never place your avocados in a plastic bag “unless you keep it open since the fruit needs to breathe during this process,” he says. “Just keep the fruit on your kitchen counter or in a warm place; 68F is the ideal temperature. Lower and higher temperatures both actually slow the process.”

Plant scientists trace the origin of the avocado (Persea americana) to south central Mexico. The avocado belongs to the flowering plant family, Lauraceae. Growers and gardeners glean tips on pest management from the industry and from the UC Statewide Integrated Pest Management Program.

Of the many known varieties, avocados fall into three broad categories based on whether they are of the Mexican, Guatemalan or West Indian races of Persea americana, the avocado species and the crosses that occur between these races. Generally speaking, California varieties have been the result of crossing between the Mexican and Guatemalan races. West Indian race varieties are not common here because of their generally lower cold tolerance.”

Ben Faber, like Linda W. Adams, enjoys avocados. He usually buys them “whenever they are reasonably priced.”

“One of the reasons I do research is that all the downed fruit is not salable because it is against food safety restrictions to introduce it into the food chain and all that fruit either gets eaten by coyotes or me,” he quips, adding “The tree is too big to fit into my backyard.”

The avocado, often thought of as a vegetable, is really a fruit and it's packed with potassium. (Photo by Kathy Keatley Garvey)

Looking for a great recipe? The California Avocado Commission offers many recipes, including what it calls “The Best Guacamole Ever."  

Dietitian Adams shares one of her favorites at https://www.delish.com/cooking/recipe-ideas/a19872947/avocado-tomato-salad-recipe/.

Avocado Tomato Salad
Ingredients

1/4 cup extra-virgin olive oil
Juice of 1 lime
1/4 tsp. cumin
Kosher salt
Freshly ground black pepper
3  avocados, cubed
1 pint cherry tomatoes, halved
1  small cucumber, sliced into half moons
1/3 cup corn
1  jalepeño, minced (optional)
2 tbsp. chopped cilantro

Directions
In a small bowl, whisk together olive oil, lime juice, and cumin. Season with salt and pepper. 

In a large serving bowl, combine avocados, tomatoes, cucumber, corn, jalapeño, and cilantro. Gently toss with dressing and serve immediately. 

Enjoy! The avocado keeps good company!

Posted on Wednesday, August 15, 2018 at 8:22 AM

The California fires situation is concerning, but not hopeless

The news that Americans are getting about California's devasting fires is not being hyped up by the media, said UC Cooperative Extension area fire advisor Lenya Quinn-Davidson on the nationally broadcast NPR program On Point.

Host Eric Westervelt of WBUR in Boston got a Northern California perspective from Quinn-Davidson, who works with communities in Siskiyou, Trinity and Mendocino counties on managing the threat of wildfires and is the Northern California coordinator of the California Fire Science Consortium. 

"I definitely don't think the situation is being hyped up," Quinn-Davidson said. "I'm in Ukiah and there's a thick blanket of smoke. Everyone can feel the tension of the Mendocino Complex Fire."

Lenya Quinn-Davidson

Quinn-Davidson said she grew up in the vicinity and, back then, major fires like those burning today only happened every few years. Lately, such super fire seasons are happening every year. She said it's time for Californians to take a different approach when thinking about fire.

"Fire is the only natural disaster that we fight against," Quinn-Davidson said. "With hurricanes and earthquakes, we adapt and try to identify vulnerabilities and change our behavior. We haven't treated fire like that. We need to learn how to adapt and make changes that make us more resilient to fire."

On Point is NPR's only call-in program. One caller asked whether climate change has reached an irreversible tipping point at which little can be done to reverse the damage that is causing extreme flooding, heat, hurricanes and wildfires.

Quinn-Davidson said she offers hope to the people in communities she serves.

"They're not powerless," she said. "I don't want people to feel that we are beyond some tipping point and they should just throw in the towel. I think we need to feel empowered to make the changes we can make - whether on a personal scale, at at the mid-grade community scale, or if it is taking political action to make larger change ... We still have some place to make a difference. I really believe that."

Michael Mann, professor of atmospheric science and director of the Earth System Science Center at Pennsylvania State University, was also a guest on the On Point program. He said that, as a nation, we may have breached a different tipping point - a tipping point in public consciousness. Recent news reports have informed the public about extreme flooding in Japan, record-breaking heat in Europe and catastrophic wildfires in California.

"This summer has made a difference in the public perception of how profound the threat of climate change already is," Mann said. "And I like to think that when they go to the voting booths in less than 100 days, they're going to be thinking about climate change and the need to act on this problem. I think we will see progress."

Posted on Wednesday, August 8, 2018 at 3:15 PM
Focus Area Tags: Environment

Farmers concerned about crops tainted by wildfire smoke

When wildfires send smoke into farmland, orchards and vineyards, growers are concerned about the impact of the tainted air on their crops, reported Giuseppe Ricapitio in the Union Democrat.

"It's grapes we worry about the most," said Susie Kocher, UC Cooperative Extension forestry and natural resources advisor. "In the past, there have been bad years when there was a lot of smoke where grapes were on the vine and wineries had to produce the smoky wine because of that effect."

The article said grapes are unlike other agricultural products, in that the skins are permeable. Free volatile phenols created by burning wood become part of the grape itself.

"It isn't something you can wash off," said Ron Harms of Yosemite Cellars winery.

After the 2013 Rim Fire, the winery produced a "Rim Fire Blend," which was successful. However, wine drinkers' palettes differ in terms of their smoke sensitivity. "Some people just can't tolerate (smoke flavor) at all," Harms said.

Other agricultural crops may not be impacted by a blanket of smoke, and some may even benefit. Before Europeans settled in California, Native Americans living in the wilderness would set fires to burn understory brush that built up in the forests.

"It's part of the ecological knowledge of native tribes that smoke is good for trees," Kocher said. "That's not a scientifically proven thing. We don't know."

Grapes are particularly to smoke taint when growing close to a wildfire. (Photo: Facebook.com/CalFire)
Posted on Tuesday, August 7, 2018 at 9:49 AM
Tags: smoke taint (2), Susie Kocher (13), wildfire (123)
Focus Area Tags: Agriculture

More sensible land use planning can help prevent wildfire losses

Climate change is only partly fueling the catastrophic fires in California. Fire scientists also lay blame on the tendency of land use planners to allow the construction of houses and businesses in areas where wildfires are a natural part of the ecosystem.

Last week Gov. Brown forecast a rise in the number, intensity, and cost of fires, warning of “the new normal that we will have to face," reported Martin Kuz in the Christian Science Monitor.

Wildfire experts say its not a new normal but has become normal because lawmakers have avoided prodding local officials, developers, and residents toward an approach to land use planning that restricts housing growth in fire-prone areas.

UC Cooperative Extension specialist Max Moritz
“If you want to keep communities safe, then you have to think about living differently, about where and how we build our communities,” said UC Cooperative Extension specialist Max Moritz. “But there's no bill in the legislature about that.”

Tomorrow's tinderboxes can be seen all over the Bay Area — from the new multi-million dollar dream homes packed along the edges of San Jose's Almaden Quicksilver County Park and Mount Diablo State Park to older residences, both modest and opulent, on peaks of the Santa Cruz Mountains and Oakland and Berkeley hills, reported Lisa Krieger of the Bay Area News Group. Similar growth is taking place in natural areas in other parts of the state, including the Sierra Nevada and Southern California.

An analysis by geographer Stephen Strader of Villanova University, published this spring in the journal Natural Hazards, found a 1,000 percent increase in the number of western U.S. homes at risk from wildfire over the past 70 years — from about 607,000 in 1940 to 6.7 million in 2010.

Housing near wildlands makes it harder to do controlled burns — one of the most effective fire suppression techniques — because of smoke concerns. Until the 1970s, fire suppression tended to minimize fire spread.

“If homes are sprinkled through the landscape, you take that key tool off the table,” Moritz said.

And as people develop rural areas, they're also more likely to ignite fires. In early California history, lightning was the major cause of wildfires. Now humans are the dominant cause of fires, from downed power lines, smoking, sparks from equipment and more.

“Now is the time to do smarter, stronger land use planning,” Moritz said, “so our future communities are not as vulnerable.”.

For more information, see Moritz' Fire Regimes and Ecosystems Management website. https://nature.berkeley.edu/moritzlab/.

The Carr Fire lights up the sky in Shasta County on July 28, 2018. (Photo: CalFire)
Posted on Monday, August 6, 2018 at 11:36 AM
Tags: Max Moritz (22), widlfire (1)
Focus Area Tags: Environment

Winners named in ASABE ag robotics competition

Ali Pourreza, left, congratulates China Agricultural University associate professor Xin Wang and the CAU Dream Team, winner of the 2018 ASABE Robotics Student Design Competition advanced division. ASABE President Steven Searcy joins them on far right.
China Agricultural University (CAU) took home top honors in the 2018 ASABE Robotics Student Design Competition, held July 31 in Detroit. CAU teams won in both the advanced and beginner divisions.

Among the advanced teams, the University of Georgia, University of Florida and UC Davis finished second, third and fourth, respectively. Zhejiang University and Clemson University claimed those runner-up spots among the beginner teams. The beginners' race was especially tight, with the top two teams achieving perfect scores. CAU used speed to edged out Zhejiang, completing the required technical task one second faster than Zhejiang. Teams from Cal Poly (6th place) and UC Merced (7th place) also competed on the beginners board.

China Agricultural University also won the beginners division.

“All the teams incorporated innovative solutions in their robot designs,” says ASABE member Alireza Pourreza, University of California Cooperative Extension agricultural mechanization specialist, who coordinated the 2018 event.

This year's challenge involved identification, sorting, and harvesting of apples. The robots were required to autonomously harvest “apples” on a field measuring 8 feet by 8 feet. The robots identified and selected eight mature apples (red ping-pong balls), removed and disposed of eight diseased or rotten apples (blue ping-pong balls) and left eight immature apples (green ping-pong balls) on the tree.

CAU Dream Team's robot picked "apples" in two lanes at once. Photo by Michael Gutierrez.

"China Agricultural University's Dream team presents one of the more prodigious designs in competition, covering two lanes at once and picking apples flawlessly," tweeted Michael Gutierrez, a University of Florida Extension water specialist, @IrriGatorUF https://twitter.com/IrriGatorUF/status/1024285164682264577.

“The increasing interest in the ASABE robotics competition every year reflects a global response to the need of automation and robotics in agriculture,” explains Pourreza, who is based at UC Davis. “We aim to motivate young agricultural engineers to engage more with robotics and acquire an early-career experience that will prepare them for the future of agriculture and smart farming.”

Cal Poly, UC Merced and UC Davis also competed in the 2018 ASABE Robotics Student Design Competition.

Fifteen university teams from the U.S., Canada and China competed in this year's contest. Sponsored by the American Society of Agricultural and Biological Engineers, the ASABE Robotics Student Design Competition allows undergraduate and graduate students to develop skills in robotic systems, electronics and sensing technologies by simulating a robotics solution to a common agricultural process.

Founded in 1907, ASABE is an international scientific and educational organization dedicated to the advancement of engineering applicable to agricultural, food and biological systems.

MORE INFORMATION: 2018 ASABE robotics competition website: https://www.asabe.org/Awards-Competitions/Student-Awards-Competitions-Scholarships/Robotics-Student-Design-Competition

Video of 2016 competition: https://www.youtube.com/watch?v=U1ymUiCr3Mc

Video of 2017 competition: https://vimeo.com/250379863

Posted on Friday, August 3, 2018 at 1:24 PM
Tags: Alireza Pourreza (3), robotics (1)
Focus Area Tags: Innovation

Next 5 stories | Last story

 
E-mail
 
Webmaster Email: jewarnert@ucanr.edu