Tuesday, October 30, 2012

A Nuisance Bug that Doesn't Stink

A fellow employee here at the Arboretum brought this to me. It was massing outside of her house in large numbers. They seem to be making there way into her house and becoming a nuisence there.  It's about a 1/2 an inch long and has really nice red markings on its thorax and abdomen. Turns out this is the Red-shouldered bug . It's listed as feeding on the seeds of Koelrueteria trees so control consists of keeping the seeds raked up off of the ground. I asked my fellow employee if she had any Koelrueteria trees around and she said that, yes, she had three of them in the same area as where the bugs were a problem.
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Tuesday, October 16, 2012

Another Possible Polyphagous Shothole Borer Infestation in Altadena

Visible ooze possibly from PSHB infestation.
I received an email from resident of Altadena who had just had a large oak transplanted this last November. The tree was not doing so well and he was wondering what was happening to the tree. Turns out the tree may be suffering from PSHB infestation. Pictures of the tree he sent me seem to show the typical 3-6 inch small oozing spots with sometimes discernable small white spots of sawdust surrounding small 1/8" holes in the bark. This is just a photo diagnosis so it is no way the final word on this tree. Although live oaks are known to be reproductive hosts for the PSHB, how destructive they might be to oaks in good health is still unknown.

3" by 2" ooze spot and entrance hole (midway on the left of the spot).
Oak trunk showing ooze spot.

Oak canopy showing thinning. How much of this thinning is due to PSHB is unknown; the tree was transplanted less than a year ago.
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Thursday, October 11, 2012

Elder Blues

I got a call about a sick 'Alder' tree that was just about dead, turns out the tree was a Box elder, a type of maple tree with compound leaves that don't look like a maple. This tree is very confusing. It's also the number one victim of the new Polyphagous Shot Hole Borer (PSHB).  This pest is just hideous and seems to be gaining new victims (known in plant pathology circles by the innocuous term 'hosts') every month.I asked the caller to send me pix of the tree by email and sure enough, it was infested with  PSHB.

Here are some of the pix he sent me:

The Box elder's confusing leaves. 
Notice the dark wet-looking patches with the mounds of sawdust in the middle of them. 

An even better look at the oozing and the sawdust spots. 

Friday, October 5, 2012

(Possible) Shot Hole Borer Blues

The Polyphagous shothole borer is starting to make the news, and rightly so. Just last week I found one of our Brazilian peppers possibly dead from the beetle/fungus combination. 

Brazilian pepper tree (Schinus terebinthifolius) that may have been killed by shot hole borer. 

Closeup of branch from possible shot hole borer infested Brazilian pepper tree. The dark stains may be from the Fusarium fungus that the beetle infects the tree with. 
This pest/fungus combination is starting to show up all over the place -it's quite an extensive infestation. Just before I started writing this post a gentleman called about his tree that was dying and emailed me some photos of it; it was a Box elder. Box elders have been the canary in the coal mine for this thing and his was located in Monrovia. I'll be writing more about it shortly, and I'm writing more extensive article about the infestation for the Arboretum website.

Pest and Disease Threats to Southern California Oaks: I'll Be Presenting At This Seminar

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