Unlock the Secrets to Healthy Avocados:

Learn about Avocado Sunblotch Viroid

September 13,2024

9am-12:30pm

The Farm Bureau,Escondido

420 S Broadway,Escondido,CA 92025

Registration link:

https://forms.gle/12LxUUdkPb8DmNdm8

Fatemeh Khodadadi fatemehk@ucr.edu(845) 901-3046

Presentations:

• Fatemeh Khodadadi: Understanding ASBVd: from discovery to diagnostic hurdles
• Elize Jooste:An overview of ASBVd in South Africa:transmission challenges and how to mitigate the spread
• Peggy Mauk:Protecting California's avocado genetic resources through sunblotch viroid detection
• Mehdi Kamali:Rapid and sensitive detection of Avocado Sunblotch Viroid Disease (ASBVd) using our digital methodology

Field Day at Pine Tree Ranch, Santa Paula

19455 E. Telegraph Road, Santa Paula, 

 Planting technique, Entomology, Pathology, New rootstocks/scions

Topics and Speakers

It is unfortunate that we allow the passing of individuals without recognizing their contributions. B. O. Bergh was an important part of the avocado industry and his passing should surely be noted. Below is his obituary:

Berthold Bergh Obituary

Berthold (Bob) Orphie Bergh January 30, 1925 - July 14, 2021 The family of Dr. Bob Bergh is deeply saddened to have to tell of the death of their husband, father, grandfather, uncle, brother, and brother-in-law. This brilliant, witty, exuberant, uproarious and completely lovable man was born the fourth of seven children, to Mina (Grambo) Bergh and Ingvald Bergh, in Domremy, Saskatchewan, Canada, on January 30, 1925. He was premature, and his mom (a nurse) kept him warm in that cold Saskatchewan weather, she told us, by putting him in a cosily lined shoe box, and setting it on the open oven door! When he was six years old, his family moved to a homestead at Chelan, SK, where they definitely lived the pioneer life. Because Chelan School offered education up to grade 11 only, he returned to Domremy and lived with his Uncle Palmer and Aunt Alice while he took grade 12. A lovely red-head was also living and working in this home, so this is where Gwen and Bob met. Following grade 12 he returned to Chelan, enlisted in the military, and in 1944 went overseas to England. His military superiors recognized him as no ordinary man, and decided they needed him as a clerk. So he spent the war years answering correspondence, keeping records, ordering supplies, working with the archives, dealing with soldiers' uniforms and furloughs. He was singled out for special honor during his Army career when Stroma Sinclair, daughter of the Duke of Portland, asked for a "nice young Canadian boy" to spend his furloughs with her in the ancestral home, Dunbeath Castle in Scotland. This was a wonderful gift to Bob, and they remained friends and in touch until her death. Suddenly the war ended and Bobby and hundreds of thousands of young Canadians returned home. He and Gwen were married in Saron Lutheran Church, Hagen, SK. on September 17, 1948. After earning his Bachelor of Agriculture degree from the University of Saskatchewan in Saskatoon, he and Gwen moved first to Columbus, Ohio, where he received his Masters Degree in Horticulture. Then it was off to Berkeley, CA, where he earned his PhD in Genetics. With no job prospects in Canada at that time for a Doctorate in Genetics, he and Gwen made the decision to stay in the USA, where he was offered a professorship at the University of California at Riverside. Here he had an illustrious career---he won the Distinguished Teacher Award several times, both for his teaching skills as well as for the rapport he had with his students. Word of this phenomenal man spread among the student body, and the high enrollment in his Genetics class often necessitated arranging for larger classrooms. Gwen has told us that long after he retired he continued to receive calls from ex-students around the world, often asking for advice on personal and spiritual matters. Bobby was a great man of faith. His research area was avocados, and for many years he had a world-wide reputation as the leading authority on the avocado. He was frequently seconded to other avocado-growing nations, including Israel, New Zealand, and Kenya. Gwen often accompanied him on these travels, and they made many friends around the globe. Bob developed a new, improved variety of avocado, named after his wife, Gwen. An offspring of the "Gwen" is marketed as the "GEM" avocado. Bob and Gwen adopted two children: Linda in 1959, and Robert in 1960. These two were loved passionately and forever! Over the years Bob and Gwen have made many trips back to Saskatchewan to see their families. And over the years they have hosted so many of us, (both Bob's family and Gwen's), to delightful California winter holidays. Bob and Gwen loved their adopted country and their many friends in the USA. Bob's extraordinary compassion, generosity and larger-than-life-presence made the world a better place. Bob was predeceased by his parents, four siblings, and numerous other relatives and friends. He is survived by his wife Gwen; his daughter, Linda Sanborn, granddaughter, Heather and grandson BJ; son Robert Bergh, grandson Justin and granddaughter Katie; two sisters, Ione Peters and Shirley Kasdorf; 7 sisters-in-law, and 7 brothers-in-law. A memorial service will be held in Hope Lutheran Church (2882 Arlington Ave., Riverside, CA) on August 19 at 1 pm. Memorial donations may be made to Hope Lutheran Church. Or plant a tree in his memory--he would like that! The Nautilus Society 16316 Hawthorne Blvd Lawndale, CA 90260 310-370-8080

To plant trees in memory, please visit the Sympathy Store.

Published by The Press-Enterprise on Aug. 1, 2021. https://www.legacy.com/us/obituaries/pressenterprise/name/berthold-bergh-obituary?id=14216300

Bob Bergh had a vision for a better ‘Hass' and worked assiduously towards this goal. The fruits of his labor are still coming mature. Aside from the 'GEM', he was also fundamental in developing the ‘Lamb Hass' and ‘Luna' varieties and helping to build the world-wide avocado industry. He was a grand man.

Avocado Trunk Cankers

This has been a low rainfall year, and often with the low rainfall, cankers will seem to suddenly appear on the woody parts of the tree. There are a number of causes for the white exudate from cankers on the trunk and limbs of avocado.  Any wound will cause the tree sap to run and crystalize on the surface.  It is a seven carbon sugar of mannoheptulose, or its alcohol form perseitol.  It's sweet.  So any wound that might be caused by woodpeckers or little kids climbing the trees will damage the bark, and where the damage has occurred, the sugar will form.  There are also diseases that can cause a wound that will exude the sugar.  Three of these are due to water stress of some form that allows infection to occur.  One of these is bacterial – Bacterial Canker.  Another is caused by a fungus which in the past was called Dothiorella Canker.  We now know it by a different name and a UCR plant pathologist has actually identified seven different species of fungus that invade the wood and can eventually weaken the tree so limbs can break and the tree becomes unthrifty.  In the case of very young trees, they can be killed by the fungus.  A third cause of sugary cankers is Black Streak, the cause of which was unclear until recently when Dr. Akif Eskalen possibly identified it. It was coming from a similar set of fungi that cause Dothiorella Canker.  It makes sense, because in all three of these cases, they most often appear after a low rainfall year, where  pressures in irrigation systems are insufficient, where emitters have clogged and where  water or salinity stress have occurred. The bacteria and fungi that cause these cankers are widely distributed in most orchards and are just waiting for the stressed tree to appear.  The grower just needs to identify where this stress is occurring, correct the problem (clogging, low pressure, poor irrigation design, infrequent scheduling, inadequate leaching, etc.) and if the damage is not too extensive, often these symptoms will disappear with time.

The fourth cause of canker is caused by Phytophthora citricola, a relative of avocado root rot.  This is caused by a moist trunk, either from irrigation water hitting the trunk, or on the north side of the tree that doesn't dry out from morning dew.  This is a much slower acting disease than root rot, although it can rapidly kill young trees.  The cankers occur at about 18 inches from the ground and gradually girdle the tree.  The first thing to do before ever seeing this disease is to make sure irrigation water isn't hitting the trunks.  If cankers appear, they respond to the same materials used for root rot, but should actually be sprayed right on the canker.

Images

Top: Black Streak can occur on trunks or branches as small, scattered  cankers.  The name comes from the blackening that occurs around the infected area.

Next: Bacterial Canker causing discrete silver dollar-sized cankers.  The exudate running down from the bottom edge results when a knife is poked into it.  The cankers tend to run in a line up the trunk or branch.

Next: Citricola crown rot with the cankers girdling the trunk.  It appears near the ground.

Bottom: Dothiorella Canker (soon to have a new name) can occur anywhere on the trunk or branches