- Author: Dani Lightle
This article first appeared in Sacramento Valley Orchard Source
Missing the Target: Why you Should Irrigate Potted Trees Directly onto Potting Media
or
Why Emitters Should be Placed on the Root Ball at Planting
Dani Lightle, UCCE Orchards Advisor, Glenn Butte & Tehama Counties
N.B. potted trees are standard commercial container grown citrus and avocado trees
Generally, when I am working with growers on a problem related to potted-tree establishment, the cause is lack of water movement into the potted media, creating tree stress. This results from the difference in soil particle size at the boundary between the orchard soil and the tree's potting soil. When you plant a potted tree in your orchard, it has a substrate – some mix of peat and vermiculite – that is very different than your soil type. The change in texture and pore size inhibits water movement from the surrounding soil into the potting media. As a result, Irrigation water applied outside the potted soil media isn't getting to the roots.
The sequence of photos in Figure 1 demonstrates this phenomenon. I set up a mock orchard condition with soil (Tehama series silty loam) next to a potted tree (potting soil) in a ½ inch wide frame. I then slowly added water to match the soil infiltration rate, similar to a drip emitter, approximately 4 inches away from the potting soil in the ‘orchard' soil.
You will see that the water does not move into the potting soil (Figure 1C & D). Two forces – gravitational pull and capillary action – move water downward and laterally in the soil. Since the potting soil is not below the orchard soil, gravity does not move water into the potting soil. Capillary action is not strong enough to move water into the potting soil because the difference in pore size is too great. So, irrigation water goes where it can easily flow – downwards and laterally into dry, native soil but not into the potting soil. More water does not solve the problem, it will just move past your newly planted trees and wet more native soil.
For about the first month of growth, irrigation emitters should be located at the base of the potted tree to ensure the potting medium receives water. Frequently check to ensure that the potting soil stays wet – not the soil somewhere else in the tree row or mound – before, after, and between irrigation sets. The best way to do this is with a small trowel and your hands. Water will need to be applied at the base of the tree until the tree roots grow beyond the potting soil and into your orchard's native soil. The time required for this to happen will vary depending on factors such as temperature, but it should take roughly a month.
Figure 1. This sequence of photos shows the movement of water applied to Tehama series silty-loam soil. Water was applied at the blue arrow, approximately 4 inches from the potting soil. Total elapsed time was 51 minutes. Water moved downwards and laterally but did not cross the boundary into the potting soil.
- Author: Ben Faber
Presented by
California Avocado Society, Inc., California Avocado Commission, and University of California Cooperative Extension
California Avocado Growers Seminars Series 2018
Scheduled Dates and Topics
February Seminar Topic
Pest Monitoring and Management
Speakers:
Tuesday, February 6, 2018, 1:00 p.m. to 3:00 p.m.,
UC Cooperative Extension Office Auditorium, 2156 Sierra Way, San Luis Obispo, CA 93401
Wednesday, February 7, 2018, 9:00 a.m. to 11:00 a.m.,
UC Cooperative Extension Office Auditorium, 669 County Square Dr. Ventura, CA 93003
Thursday, February 8, 2018, 1:00 p.m. to 3:00 p.m.,
Fallbrook Public Utility District Board Rm., 990 East Mission Rd. Fallbrook, CA 92028
April Seminar Topic
Old and New Smart Agriculture
Speakers:
Khaled Bali: Irrigation Specialist, Kearney REC
Alireza Pourreza: Ag Engineer, UC Davis
Tim Spann: California Avocado Commission Research Program Director
Dates/Times/Locations:
Tuesday, April 17, 2018, 1:00 p.m. to 3:00 p.m.,
UC Cooperative Extension Office Auditorium, 2156 Sierra Way, San Luis Obispo, CA 93401
Wednesday, April 18, 2018, 9:00 a.m. to 11:00 a.m.,
UC Cooperative Extension Office Auditorium, 669 County Square Dr. Ventura, CA 93003
Thursday, April 19, 2018, 1:00 p.m. to 3:00 p.m.,
Fallbrook Public Utility District Board Rm., 990 East Mission Rd. Fallbrook, CA 92028
June Seminar Topic
Irrigation: Selection of Sensors, Emitters, Injectors and Reading Water Reports
Selection of sensors, emitters
Dates/Times/Locations:
Tuesday, June 5, 2018, 1:00 p.m. to 3:00 p.m.,
UC Cooperative Extension Office Auditorium, 2156 Sierra Way, San Luis Obispo, CA 93401
Wednesday, June 6, 2018, 9:00 a.m. to 11:00 a.m.,
UC Cooperative Extension Office Auditorium, 669 County Square Dr. Ventura, CA 93003
Thursday, June 7, 2018, 1:00 p.m. to 3:00 p.m.,
Fallbrook Public Utility District Board Rm., 990 East Mission Rd. Fallbrook, CA 92028
August Seminar Topic
Grower Seminar and Field Tour
Details to come.
Dates/Times/Locations: One site only
Wednesday, August 1, 2018, 10:00 - 2:00 p.m.,
South Coast Research & Extension Center Conference Room, 7601 Irvine Blvd., Irvine, CA 92818
- Author: Ben Faber
Harry S. Smith, was born in 1883 to a poor farming family in Nebraska. He was trained in Biological Control in the northeast U.S.A. where he worked on the biological control of gypsy moth with the USDA. Upon his appointment to Sacramento in 1913 to work on biological control issues important to California, Smith brought recognized entomological training in biological control to California for the first time.
The phrase “Biological Control” was first used by Smith in August 1919 at the meeting of Pacific Slope Branch of the American Association of Economic Entomologists at the Mission Inn in downtown Riverside.
Based on his experiences on biological control of forest and pasture pests, Smith brought caution and tempered exaggeration about biological control in California as he worked with citrus growers and other commodity groups.
In 1923, Smith and four colleagues moved from Sacramento to the University of California Riverside Campus which had evolved from the Citrus Experiment Station (est. 1915) and he formed the Division of Beneficial Insect Investigations which was a unit distinct from the Division of Entomology. Prof. Harry, as he was
affectionately known, is fondly remembered by his students as a patient and generous supervisor who encouraged research and work on applied and
practical aspects of biological control.
Smith went on to create the Department of Biological Control which offered the only graduate training in Biological Control in the world. The Department of Biological Control became the Division of Biological Control in 1969 which then merged into Department of Entomology at UC Riverside in 1988. Prof. Harry had two sons, both trained to be entomologists. Instead of pursuing biological control they went into the pesticide industry and Sam Smith died accidentally from pesticide poisoning. Prof. Harry passed away in 1957 and left UC Riverside $15,000 to develop a scholarship fund to support training and education in biological control. This fund has grown to approximately $45,000 today, but is insufficient to provide meaningful support to students wanting to be trained in biological control.
Our goal is to build the Harry S. Smith Scholarship fund to a significant level where the corpus of the fund will be able to generate enough revenue to provide substantial support to students wanting to be trained in biological control. This can only be achieved by actively soliciting donations from individuals, industries, and organizations that have benefited over the years from biological control projects that have that have been run by UC scientists, in particular entomologists at UC Riverside. If biological control is to continue to prosper in southern California we need to continue recruiting and training high quality students. To do this, we need to be able to provide substantial financial support, and the Harry S. Smith Scholarship is one way to attract excellent students to UC Riverside.
Learn more about the program and how you can push the fund over the top at:
http://biocontrol.ucr.edu/hoddle/harrysmithfund.html
- Author: Cheryl Wilen
IPM Natural Resources Extension Coordinator
Endemic and Invasive Pests and Diseases Strategic Initiative Leader
UC Statewide IPM Program & UCCE- You need to get a Remote Pilot Airman Certificate (FAA Part 107) if you are going to do anything commercial with it. That includes even if you are using it on a job where you will not be paid.
- You can use it for scouting but you can't fly it over people (unless you get a waiver). You also always have to have it in your or an assistant's (the spotter with radio communication) line of sight.
- Even if you have a drone that is capable of doing a spray application, the Dept. of Pesticide Regulation currently requires that the drone pilot have an Airman's Certificate (Pilot's license). This is addition to the Pest Control Aircraft Pilot Certificate from DPR. However, things may change in 2018. See pages 3-47 to 3-52 in http://www.cdpr.ca.gov/docs/enforce/compend/vol_1/entirerep.pdf
2017 The Regents of the University of California. All Rights Reserved
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- Author: Jesse Morrison
Have you ever thought about it? I'm sure a lot of you have…what's the biggest living thing on earth? If you're like me, you immediately think of animals like the blue whale. In this case, we're just talking about organisms that spend their life predominantly or entirely on land. Anybody thinking of the rhinoceros, or maybe the African elephant? Nope!
The answer to this question might surprise you. The largest terrestrial organism on the planet is actually a fungus! Not your typical, garden-variety mushroom, but a fungus, nonetheless. And while it is edible, it comes with a few problems. Its common name is honey fungus.
The soil is filled with living organisms, large and small. Bacteria are the most numerous soil organism – there can be more than a million in a teaspoon of soil! There are over 10 trillion types of soil bacteria!
There are “only” 100 billion types of soil fungi, but they play in important role in the life cycle within the soil. Fungi break down decaying plant material into nutrients that other plants can use to grow. They soak up water in water-logged soils. You might be familiar with seeing mushrooms growing on moist logs, or in soil with wet leaves.
Honey fungus is a bit different from many other fungi. It's not one that landowners will welcome because it can kill trees. In fact, it gained fame in the late 1990s as the “culprit” that was killing fir trees in the Pacific Northwest. (Fir trees are widely sought after as beautiful landscape plants, Christmas trees, and for lumber used in building homes.)
Honey fungus is a parasite – Armillaria solidipes. Parasites are organisms that live off other organisms, sometimes hurting them. Honey fungus is widely distributed across the cooler regions of the United States and Canada. It is very common in the forests of the Pacific Northwest.
These fungi grow in individual networks of above and below-ground fibers called mycelia. Mycelia work in a similar fashion to plant roots. They draw water and nutrients from the soil to feed the fungus. At the same time, they make chemicals that are shared with other organisms in the soil. Sadly for the fir trees, the honey fungus can kill already weakened or stressed trees. The natural action of this fungus can be destructive in forests, leading to widespread die-off in timber stands.
One cool feature of the underground network of mycelia of all fungi is that they help hold soil particles together. Just like plant roots, mycelia work to prevent soil particles from blowing away in the wind or being taken away by running water. They are a very important part of the soil ecosystem.
Scientists have shown that Armillaria solipipes identify and connect to each other. That's right: when mycelia from different individual honey fungus bodies meet, either in or on the soil surface, they can attempt to fuse to each other. The fungi must be genetically identical honey fungi. When the mycelia successfully fuse to each other, they link very large fungal bodies together. This, in turn, changes extensive networks of fungal “clones” into a single individual.
The largest honey fungus that has been identified in North America is located in Oregon. It measures 3.4 miles across! Scientists also believe that this particular honey fungus may be over 2,000 years old. The next largest honey fungus is in the neighboring state of Washington.
While honey fungus is impressive in both age and size, it isn't always a favorite of scientists and landowners because of its parasitic nature. But it is the largest organism on earth, and scientists have had only a few decades of research to understand how mycelia fuse and communicate. Perhaps one day, research discoveries about honey fungus could lead to a new medicine (think Penicillin), or new ways to grow food – the possibilities are endless!
And this is the largest terrestrial organism. Who knows what lurks in the depths of the ocean?
P.S.
Armillaria solipipes is one of the many species that was once lumped as Armillaria mellea, oak root fungus. So many woody perennials are susceptible to this fungus. It turns out that avocado for whatever reason tends to be somewhat more tolerant of oak root fungus than many other trees. Under stress, it too will succumb, though.