Posts Tagged: canker disease
Cold Fall and Arid Winter Conditions Wreak Spring Havoc in Some Vineyards
Hello Fodder Friends! This spring I've taken many farm calls from grape growers in Amador and...
Comparison of minimum daily temperatures in fall 2020 from foothill PMI stations.
A Sign of the Times: Why This Black Walnut Tree Is Dying
If you've ever walked into the courtyard on the 100 block of E Street in downtown Davis, Calif.,...
Forest entomologists Steve Seybold (right) and Jackson Audley stand by a 150-year-old black walnut tree on the 100 block of E Street. It is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)
Walnut twig beetles tunnel into branches and trunks of walnut (Juglans) where they create galleries for mating and reproduction. In association with a canker producing fungus, Tthey cause a disease known as thousand cankers disease. This tree is in downtown Davis, Calif. (Photo by Kathy Keatley Garvey)
This massive, 150-year-old black walnut tree on the 100 block of E Street, Davis, is dying of thousand cankers disease. (Photo by Kathy Keatley Garvey)
UC Ag Experts Talk - Avocado
UC Ag Expert talks about avocado diseases
Following the recent webinar on Citrus Thrips presented by Beth Grafton-Cardwell, a second webinar on Avocado Diseases will be offered in November. Check out the Thrips webinar and if interested enroll in the avocado one.
https://ucanr.edu/sites/ucexpertstalk/Past_Webinars/
or on YouTube
Date: November 14, 2018
Time: 3:00 PM - 4:00 PM
Contact: Petr Kosina pkosina@ucanr.edu
Sponsor: UC Ag Experts Talk
Location: Webinar
Event Details
Register in advance for this webinar:
https://ucanr.zoom.us/webinar/register/WN__Bj1TCaVSHG6RKg3-ASXuw
Ben Faber, UCCE Ventura Farm Advisor, will talk about avocado diseases. He will cover the identification and biology of root rot, crown rot, bacterial canker, leaf/stem blight, black streak and sun blotch. Then he will discuss the management management practices to prevent these diseases and the chemicals available to treat them. Resistance management tactics will be discussed.
Event Reminder
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avocado black streak 1
Decline of coast live oak trees in S. California is due to fungus
“We have found declining coast live oak trees throughout urban landscapes in Los Angeles, Orange, Riverside, Santa Barbara, Ventura and Monterey counties,” said Akif Eskalen, UC Cooperative Extension specialist in the Department of Plant Pathology and Microbiology at the University of California, Riverside.
Eskalen recovered the fungal species, Geosmithia pallida, from tissues of infected coast live oak trees and performed pathogenicity tests on it in his laboratory at UC Riverside. The tests showed that the fungus is pathogenic to coast live oak seedlings and produces symptoms of foamy canker.
The western oak bark beetle, which spreads the fungus, is a small beetle — about 2 millimeters long — that burrows through the bark of the coast live oak tree, excavating shallow tunnels under the bark across the grain of wood. Brown in color, this beetle is native to California. Female beetles lay their eggs in the tunnels. It is not known at this time if the beetle infects trees other than coast live oak trees.
Symptoms of foamy bark canker disease include wet discoloration on the trunk and main branches of the infected coast live oak tree. This discoloration surrounds the entry holes that the western oak bark beetle makes to burrow into the tree. Multiple holes can often be seen on an infected tree.
“When you peel back the outer bark of the infected area, you see bark (phloem) necrosis surrounding the entry hole,” Eskalen said. “As the disease advances, a reddish sap may be seen oozing from the entry hole, followed by a prolific foamy liquid. This foamy liquid, the cause of which remains unknown, may run as far as two feet down the trunk.”
Eskalen explained that when the infection is at an advanced stage, the coast live oak tree dies. Currently, no control methods are in place to control the fungus or the beetle.
If you suspect your coast live oak tree has the symptoms described above, please contact your local UC Cooperative Extension advisor, pest control adviser, county agricultural commissioner's office or Eskalen at akif.eskalen@ucr.edu.
To see more photos, visit http://ucrtoday.ucr.edu/22096.
New pest alert for Foamy Canker Disease on Coast Live Oak
UCR's Plant Pathology and Entomology team just issued a new alert for a pest affecting Coast Live...