Re: tipus and lerpy eucalyptus

Susan Smith

Paul et al. , Concerning the drop in lerp infestations in eucalyptus, I read in one study (Dahlsten et al 2005) which measured the decline in lerp densities  in Southern California after multiple releases  (1999 through July 2002) of the biological control (the parasitic wasp,   Psyllaphaegus bliteus from Australia). They  found lerp densities  had decreased as much as 78-79% after these releases.   This was published in 2005, so I would imagine the decline in lerp densities since then may be even more.    We have noticed a big decline in densities at the San Diego Botanic Garden, too.  Sue 

Susan Smith 
Seiurus Biological  Consulting 
Del Mar, CA 

-----Original Message-----
From: lehman.paul@... via <lehman.paul@...>
Sent: Mon, Sep 13, 2021 4:48 pm
Subject: [SanDiegoRegionBirding] tipus and lerpy eucalyptus

My impression while birding and otherwise checking quite a few areas of
south county for the past several weeks is that almost all tipu trees
are fairly dead, bird-wise. Some years they seem to attract reasonable
numbers of warblers, etc., already by latter September, but other years
they are not good until much later. Last year, they were very slow until
almost mid-November. This year seems to be following that same scenario,
so far. And while last year was good for many patches of birdy lerpy
eucalyptus, this year seems to have substantially fewer infected trees,
and few birds. I can find only a couple patches (e.g., in Tierrasanta)
with active, fresh lerps, whereas many of last year's patches are not in
use and mostly birdless. It would be very helpful to other birders if
folks who DO find active, bird-rich lerp areas, let others know!

--Paul Lehman, San Diego

Susan Smith
Seiurus Biological Consulting
Del Mar, CA

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