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Posts Tagged: trees
What is wrong with my peach tree?
In this weekly blog, Dr. Annemiek Schilder, Director, UCCE Ventura County and Hansen Agricultural Research and Extension Center, shares her observations about the natural world across the seasons. As she says:
"Gently observing your surroundings with curiosity will teach you some amazing things. There are so many fascinating things happening under our noses, only wanting for an observant eye."
"What is wrong with my peach tree?"
Many people have probably asked this question as they have stared in concerned wonder at the distorted leaves of their peach trees. From a distance the striking color patterns may even look like peculiar flowers. Peach leaf curl is a disease of peach and nectarine trees caused by the fungus Taphrina deformans, an apt name for this fungus. Ornamental peach trees, grown for their beautiful blooms, are also susceptible to this disease.
Peach leaf curl is a common plant disease featured in many plant pathology textbooks. It may well have been the disease that convinced me to become a plant pathologist (a plant doctor) as I peered with increasing fascination at its structures under the microscope.
Allow me to digress a little to discuss that great invention: the microscope. In the late 1600's, Antonie van Leeuwenhoek, a self-taught Dutch scientist, developed a single lens microscope with up to 300 times magnification, allowing observation of bacteria for the first time. He called them “little animals”. However, it would take another 200 years before bacteria and fungi were officially recognized as causes of disease in animals and plants, laying the groundwork for modern-day medicine.
The name of this disease, peach leaf curl, is quite descriptive as the fungus causes leaves to curl and develop blister-like areas. Rainy, cool springs promote infection - as well as spore production - on infected leaves. Spores are spread by wind and rainsplash to other leaves, where they can cause new infections. The disease is not only unsightly –except to the eyes of a plant pathologist, of course - but also causes diseased leaves to drop prematurely, which weakens the tree and may lower fruit yield. In severe cases, repeated defoliations can kill a tree.
Taphrina deformans spores are produced in elongated structures called asci, a Latin word meaning “sacs”.
Have you noticed that Latin is used a lot for botanical descriptions? This is because Latin is a “dead” language and thus grammatically stable.
Taphrina's asci are lined up in layers on the leaf surface without any protective covering; therefore they are termed “naked asci”. So guess what name my Plant Pathology student volleyball team chose? Indeed, our t-shirts sported botanically correct drawings of Taphrina's asci, causing the other teams to think of us a bunch of weird science nerds. Nerds who played a pretty good game of volleyball mind you!
So what can you do to keep your trees healthy? Here are a few tips.
- If you are thinking of planting a peach or nectarine tree, investigate whether resistant varieties are available so you can avoid the problem altogether.
- For established trees, fall pruning of diseased shoots may help.
- Also for established trees, (organic) copper fungicide sprays in late fall after leaf drop and before budbreak in the spring may help.
- Addition of a horticultural oil may improve spray coverage. Be sure to follow the instructions on the label carefully.
If your tree got whacked by the disease, infected leaves will fall off and new leaves will develop but this requires the tree to expend additional energy. A foliar fertilizer application as well as fruit thinning can help the tree recover.
Related Reading:
/h4>/h4>Irrigation Methods Based on Plants
I just came across a wonderful summary of the different methods that can be used to schedule irrigations based on plant sensors. In th past this is has been labor intensive and not easily adapted to commercial agriculture. This review covers some of those problems and how they have or not been overcome by new technologies. Of course, plant-based techniques are the not the only way to schedule and may only be part of the variety of methods used, such as soil-based ones like tensiometers; or weather-based ones, like ET. A shovel and just looking at trees helps too.
Plant-Based Methods for Irrigation Scheduling
of Woody Crops
ABSTRACT
The increasing world population and expected climate scenarios impel the agricultural sector towards a more efficient use of water. The scientific community is responding to that challenge by developing a variety of methods and technologies to increase crop water productivity. Precision irrigation is intended to achieve that purpose, through the wise choice of the irrigation system, the irrigation strategy, the method to schedule irrigation, and the production target. In this review, the relevance of precision irrigation for a rational use of water in agriculture, and methods related to the use of plant-based measurements for both the assessment of plant water stress and irrigation scheduling, are considered. These include non-automated, conventional methods based on manual records of plant water status and gas exchange, and automated methods where the related variable is recorded continuously and automatically. Thus, the use of methodologies based on the Scholander chamber and portable gas analysers, as well as those of systems for measuring sap flow, stem diameter variation and leaf turgor pressure, are reviewed. Other methods less used but with a potential to improve irrigation are also considered. These include those based on measurements related to the stem and leaf water content, and to changes in electrical potential within the plant. The use of measurements related to canopy temperature, both for direct assessment of water stress and for defining zones with different irrigation requirements, is also addressed. Finally, the importance of choosing the production target wisely, and the need for economic analyses to obtain maximum benefit of the technology related to precision irrigation, are outlined.
https://www.mdpi.com/2311-7524/3/2/35/htm
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drone measuring trees
Celebrate Earth Day with Gardening and Other Stay-at-Home Resources
This week marks the 50th anniversary of Earth Day. This year, consider celebrating the day with gardening and other stay-at-home resources curated by your local UCCE office.
History of Earth Day
Earth Day was launched in 1970. Many factors contributed to the call for a national day focusing on environmental stewardship, including the publication of Rachel Carson's Silent Spring - serialized in the New Yorker - and the catastrophic oil spill that occurred off the coast of Santa Barbara in 1969. The Santa Barbara oil spill galvanized U.S. Senator Gaylord Nelson (D-Wisconsin) to call for a national day of locally inspired and organized "teach-ins" on the environment - a national "Earth Day." The Earth Day model was inspired by the spirit of campus activism at the nation's colleges and universities. It wasn't top-down, but rather a grassroots effort that encouraged communities to develop educational and service events around issues and topics important to them.
Earth Day struck a chord; some estimates suggest that 1 in 10 Americans participated in the first events. Earth Day is widely credited with "sparking" the modern environmental movement. Landmark environmental legislation swiftly followed (including the Clean Air Act, Clean Water Act and Endangered Species Act). The Environmental Protection agency was founded that same year. Twenty years after its launch, Earth Day became a global movement.
You can learn more from the Earth Day Network by linking to this website.
Home Garden Resources
There is a wave of renewed interest in gardening as a result of the COVID-19 pandemic. Learn more about "crisis" gardening - and a new "Victory Garden" movement - in this article from the New York Times.
Closer to home, we have a wealth of gardening resources for you.
One of our favorites is the California Garden Web, designed by our UC Master Gardeners. You'll find a wealth of gardening information and a helpful glossary.
Ventura County is blessed with a wonderful growing climate and many of us have backyard fruit trees. Learn more about cultivating and caring for your home orchard here.
Resources for the Home Classroom
Many of us are working with our children in home classrooms. The UC 4-H Youth Development Program has a range of resources available to engage young learners. In honor of Earth Day, take a look at our 4-H Vegetable Gardening Project sheet. We also recommend our 4-H Water Conservation Project sheet, which provides engaging, science-based activities the entire family can enjoy. 4-H is one of the oldest youth development programs in the nation and we'll be sharing other educational resources in upcoming posts. #Head #Heart #Hands #Health.
![10haydensmith-p19jh073u6et71lstppflvbh5-212x300 10haydensmith-p19jh073u6et71lstppflvbh5-212x300](http://ucanr.edu/blogs/venturacountyucce/blogfiles/69233.jpg)
Be Kind to the Earth by Reducing Food Waste
Nearly 40 percent of the food produced in the U.S. is wasted and much of that waste ends up in landfills (definitely not good for our environment or the economy).
The National Resources Defense Council estimates that the average family of four throws out nearly 1,000 pounds of food each year, wasting roughly $1,500.
Consumers as a group waste more food than farms, grocery stores or restaurants. For tips on ways you can reduce #FoodWaste, click here.
History lesson: The image on the left is a poster that was used during World War I and World War II to promote food conservation. First printed in 1919, it contains tips that are helpful today.
This image is from a collection held by the Museum of County. Photographer: Aysen Tan.
Related reading: What a World War I Poster Can Teach Us About #FoodWaste.
Thank you, Volunteers!
This week is National Volunteer Week and we want to thank the hundreds of volunteers who are part of UCCE Ventura...and who make our work possible. Thanks to our 4-H, Master Gardener and HAREC volunteers. You are central to our mission and we value you. Youth, Families and Communities Education Program Manager Susana Bruzzone-Miller created this video to express our appreciation.
COVID-19 Resources
Our COVID-19 landing page provides links to important resources about the pandemic, including information for the agricultural community. In response to the coronavirus (COVID-19) illness, our office is closed for face-to-face service through May 15th. While we regret the inconvenience, these are the precautions we are taking to support one other and comply with University, local, county and state government recommendations. Our staff is telecommuting and can be contacted via phone and email. We are here to serve you.
Stay safe.
/h3>/h3>/h3>/h3>/h3>/h3>/h3>/h3>Thank you UC HAREC Volunteers
Will Deciduous Fruit Trees Flourish in Ventura in 30 Years?
That's a good question. Some question whether they flourish now. Southern California does not have the landscapes of apples, pears and peaches of Oregon, Michigan, Pennsylvania or even Fresno, but there are nice little niches of persimmon, low chill apple, and even blueberries that thrive in the lower winter chilling environments along the coast and in the south of California.
Here is an example of what might happen to this fruit industry here. A recent, detailed study extrapolate the accumulation of cold periods in Spain over the next 30 years and to the end of the century. This provides growers with important information on the viability of future fruit cultivation in the various Spanish regions, as it allows them to know if there will be the necessary accumulated cold for the fruits to grow correctly or if they should relocate their crops to other areas.
The results obtained show a general reduction in the accumulation of cold in any future period for all the chilling models and scenarios considered. The reduction is especially significant at the end of the century, under the most pessimistic scenario. These results invite us to strongly commit, not only to adapt but also to mitigate climate change, something that would make an important difference. The probable reduction of cold would threaten the viability of some varieties of fruit trees in the near future, especially in regions where there is currently a low accumulation of cold and there are varieties that require a lot of it.
The study can be viewed at:
https://www.nat-hazards-earth-syst-sci.net/19/1087/2019/
Climate change discussions for California can be found at these websites:
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=30513
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=28175
An intriguing Santa Barbara apple study grower's observations are worth noting: https://ucanr.edu/blogs/Topics/index.cfm?start=1&tagname=apples
By the way the 'Moor Park' apricot is not from Moorpark, CA, but from England and the variety has never done very well in Moorpark (http://www.ngr.ucdavis.edu/treedetails.cfm?v=997).
apple image 2
Avocados & Other Trees Blog
It's so nice to be able to find a way to rapidly answer homeowner questions. Once one questions has been addressed, invariably another one pops up. There are mysteries to plants and they can go on and on forever. The University of California Cooperative Extension has locally trained volunteers to answer the questions that local homeowners are going to ask about local plant problems. You can find Master Gardener contacts by going to the map to find a local office and the local MG Helpline: http://ceventura.ucanr.edu/Offices/
Recently I got an email from a homeowner that had a burning question about the name of an avocado found in a picture. That one question lead to another and to another and eventually to how to plant a tree in a heavy clay soil. i was going through explanations, and suddenly remembered a website put together by Greg Alder with photo steps going through the whole process: http://gregalder.com/yardposts/how-to-plant-and-stake-an-avocado-tree/
After passing that link on to the homeowner, I havent had any more questions about planting avocados. The site does the trick.
So if you are looking for more answers about avocados, the Annual Meeting of the CA Avocado Society is October 4 - next month. Come on the tour and see how it's done:https://californiaavocadosociety.org/annual-meeting.html
Filling a planting hole to see if water drains well enough before planting an avocado. A great photo from the blog.
filling a hole