- Author: Cris L. Johnson
Once a tree has been infected by the psyllid that carries and transfers the huanglongbing (HLB) bacteria to the tree there has been no alternative but to quarantine the infected area and destroy the tree. To complicate the issue further, the disease can lie dormant and be difficult to detect as the infection spreads from tree to tree.
Efforts to control the psyllid through pesticides have been ineffective and while quarantines have helped raise awareness and slowed some of the spread, a viable weapon to combat this invasive pest has been unavailable until recently.
Mark Hoddle, director at the Center for Invasive Species Research at UC Riverside, has been experimenting with a tiny parasitic wasp, Tamarixia radiata, that feeds on and kills the psyllid. After a series of tightly controlled and successful tests, the wasps have been released on infected sites and have been effective in reducing the psyllid population. There is no danger to pets or humans and the release program has been approved by the Department of Agriculture.
To learn more about this effort, please see the UC Riverside Newsroom article.
- Author: Cris L. Johnson
The website explores chemical injury, nutritional disorders, physical and physiological disorders found in the field and during research. The team collaborates and shares information about these issues and discuss methods for dealing with them.
The website is presented in English and in Spanish and is accompanied by large photos that focus on the problem areas.
Check out the new website: Strawberry Disorders: Identification and Management.
- Author: Cris L. Johnson
The latest issue has recently been posted on our website and features articles on:
Cultural Practices to Reduce Pest and Disease in Avocado and Citrus. This article by UC Ventura County Cooperative Extension advisor Dr. Ben Faber provides guidelines for practices from selection to maintenance that can mitigate disease and pests in trees.
Polyphagous Shot Hole Borer in California. UC Cooperative Extension cross-county advisor Dr. Sabrina Drill discusses this pest and it's effects on Southern Californian trees.
Electronic "sniffer" for Detecting HLB. Dr. Faber also reports on a new device that can detect Huanglongbing (HBL) disease in trees. Learn more about how it works and the advantage it could provide in preventing HLB spread through early detection.
Important Information Sources Related to Fire Management and Protection. The fire season is still on us and this list of online and publshed resources provides useful information for property owners.
Bee Kill in Oregon - A reminder of pesticide use. The State of Oregon has issued a moratorium on an aphid control pesticide after its use killed a large amount of bumble bees. Read more about following the proper guidelines on pesticide use here.
Read the full articles from this newsletter or check out other issues of Topics in Subtropics here.
- Author: Cris L. Johnson
SAVE THE DATE.... February 28, 2013.
UC Ventura County Cooperative Extension (UCCE) in cooperation with the Hansen Agricultural Center is hosting a Landscape Disease Symposium that focuses on the formation, spread and control of disease in landscape plants.
This annual event is organized by UCCE Ventura plant pathology advisor Dr. Jim Downer. He and other plant experts will speak on topics relevant to landscapers such as pathogens in fire injured trees, creating suppressive soil, wood decay, and disease from wood boring insects.
Pre-registration fee: $75.00
Door registration fee: $100.00
To register and pay online: Landscape Disease Symposium registration
Location:
Hansen Agricultural Center
14292 Telegraph Road
Santa Paula, CA
Contact: Dr. Jim Downer, ajdowner@ucanr.edu
For agenda and more information see the flyer.
Dr. Downer also writes "Landscape Notes," a newsletter with articles of interest to professional and home landscapers. You can link to these newsletters here.
- Author: Cris L. Johnson
The latest issue has recently been posted on our website and features articles on:
Simazine degradation in California citrus orchards. This article focuses on research performed in response to concerns about the effectiveness of simazine as a means of weed control. Here you can read about the experiments performed to test degradation levels and recommendations made regarding use of this herbicide for weed control.
Lime-induced iron chlorosis. Iron deficiencies in many fruit trees can be escalated where soils and irrigation water contain lime which can in turn impede soil drainage. Iron oxides serve as a common source of nutrition for the trees and the deficiency of it can cause dieback and other disorders. This article explores the causes and possible treatments for this condition.
Avocado trunk cankers. UCCE Ventura citrus, avocado and subtropicals advisor, Dr. Ben Faber, contributed this article on the various types and causes for tree cankers. Wounds to the tree, low rainfall, fungi and moisture can promote this disorder.
Asphyxiation. Dr. Faber also explores the problem of asphyxiation that occur in parts or all of the tree. This condition can seriously harm the tree and Dr. Faber discusses some methods of treatment and prevention.
Tree wraps. This article presents information about some of the benefits and considerations in installing wraps on young trees.
Stem and leaf blight. Dr. Faber also wrote this item on blight that he has observed lately on local trees and how insufficient water can contribute to the condition.
Read the full articles from this newsletter or check out other issues of Topics in Subtropics here.