Off topic: aphid preference for a weed

Roy M. Sachs rmsachs@ucdavis.edu
Tue, 14 Oct 2003 10:04:20 PDT
For the past year I've seen little or no black or green aphids on 
alstroemeria, but multitudes of them on Crepis species (they are 
pernicious annual weeds in my greenhouse, field and shade shelters). 
Most of the aphids don't begin to go to the Crepis until they have 
begun to bolt, form an inflorescence axis.

The USDA has a page-full of Crepis pics at, 
http://plants.usda.gov/cgi_bin/plant_profile.cgi/….

Can't find mention of this in our Integrated Pest Management pubs. 
Anyone out there with info or can confirm this seeming preference of 
aphids for Crepis?

Also I should note that our rabbit population seems to prefer the 
Crepis (before bolting when they are excellent salad leaves) to 
alstroemeria...not that I'm trying to feed the rabbits.

Roy
Davis, California; Sacramento Valley, very hot summers (over 40 C), 
wet and cool winters (rarely down to -4 C except when Siberian 
express drops temps to -8 C) with moderate spring and fall temps. 
Dry winds are the norm in summer and fall.


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