Posts Tagged: pest note
Widow Spiders Information Updated
The black widow spider is known and feared by many people due to its venomous bite. However, in the...
Huanglongbing Detected in Cerritos, Los Angeles County
[News release from the Citrus Pest & Disease Prevention Program] An intensive risk survey in...
Citizens Concerned about Sudden Oak Death in San Luis Obispo County
From the ANR News Blog Central Coast residents, officials, ranchers and representatives of...
Hi! Ho!...Hi! Ho!... Who's Been Mining My Citrus?
Advice From the Help Desk of the UC Master Gardener Program of Contra Costa County
Client's Question: The photos show what several of my dwarf lemon tree's leaves look like. I had several leaves look the same last year, but I thought it was just a one-time occurrence and would go away when I took them off the tree awhile ago. However, as you can see on the picture, the condition is back. What is it and what can I do to protect the tree and fruit.
Response from the UC MGCC Program's Help Desk: This condition n the photo is not a disease. It is caused by an insect that,during its immature stages, burrows (“tunnels”) in the leaves. The insect is called a Citrus Leaf Miner. When it becomes an adult and exits the tunnels, it is a moth. Although the burrowing causes the leaves to become distorted, the leaves still provide food for the plant, so you should not remove them. There will not be any lasting damage from this insect. There is not any spray that can prevent this, because the insect larva is protected inside the leaf. The best way to reduce the infestation is to not fertilize your citrus during summer or fall, since this is the time the moth is active. Fertilizing causes new growth, and the new leaves are much more susceptible to the Leaf Miner than older, hardened leaves. Citrus should also not be pruned during this time, again because pruning also causes new leaves to emerge.
Citrus should be fertilized before bloom (January or February), and again in May. If fertilizer is needed (e.g., if the leaves are not a deep green color), apply additional fertilizer no later than June. Always follow label directions when applying fertilizer. More recommendations regarding fertilizer for Citrus can be found here
http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/CULTURAL/citfertilization.html
Additional information about Citrus Leaf Miner can be found at this University of California website http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74137.html
Help Desk of the UC Master Gardener Program of Contra Costa (JL)
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Editor's Addendum: The Citrus Leaf Miner has been in California for many years, mainly in Southern California. However, it became very obvious in Contra Costa County only a few years ago. I've seen Citrus Leaf Miner in my various citrus trees in Martinez for the last several years, and we've had many questions about Leaf Miner at the Help Desk for the last 2-3 years. In my citrus, it hasn't been a significant impact, but it is noticeable due to the obvious tunneling and distortions. Per the referenced Pest Note, I haven't really done anything to prevent and/or “cure” the infestation other than normal care. Anecdotally, the impact didn't seem to be as significant last year (2015), and I haven't really noticed any impact so far this year. The Pest Note indicates that there are natural predators that often follow the Leaf Miner so maybe they have finally arrived (woke up?) or some other predator has discovered this new “food”? We'll soon see as warmer weather arrives.
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Come to the UC MGCC Program's Great Tomato Plant Sale
Walnut Creek 4/2&9, Richmond 4/9, and Antioch 4/16
Click for locations and plant lists!
Dozens of heirloom tomatoes & vegetables chosen especially for Contra Costa
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/).
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UC IPM Releases Management Guidelines for Goldspotted Oak Borer
First identified in California in 2004, the goldspotted oak borer (GSOB), Agrilus auroguttatus, has killed more than 24,000 oak trees in San Diego County since its arrival, probably in the late 1990s. In 2012, it was detected in Riverside County and it is expected to spread northward in the state.
The most seriously damaged oaks are those in the red oak group including coast live oak, Quercus agrifolia, and black oak, Q. kelloggi. It also infests canyon live oak, Q. chrysolepis but has not been found to kill the other native oak species in the area, the Englemann oak, Q. englemanni. So far losses have been most serious in parks and forested areas, but landscape trees are also being killed.
A new Pest Note from the UC IPM program outlines management guidelines for this serious pest. Flatheaded borers such as GSOB are difficult to manage and seriously infested trees cannot be saved. The primary way GSOB spreads into new areas is through the movement of infested wood and the authors recommend leaving infested wood on site for 2 years. If wood is to be moved, the Pest Note provides guidelines for treating it through containment, grinding, and debarking. Guidelines for replanting infested areas, less susceptible oak species, biological control, insecticide applications and developing GSOB management plans are also described.
Many other borers attack oaks but do not kill trees. GSOB infested trees can be distinguished by the characteristic D-shaped emergence holes it leaves behind. A special feature of the Pest Note is a table illustrating the emergence holes of borer species on southern California oaks. Many photos are also included.
The information in this Pest Note: Goldspotted Oak Borer is based primarily on research studies by the authors: Mary Louise Flint (UCIPM and Entomology/UC Davis), Tom Coleman and Steve Seybold (USDA/US Forest Service), and Mike Jones (Entomology/UC Davis). Find it at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74163.html