My douglas fir is infested with these bugs. Does anyone know what these are?
I live in northern california.
CLOSED: Douglas fir bug infestation
These are aphids, but I cannot be more specific from this image. See http://www.fs.usda.gov/detail/r10/forest-grasslandhealth/?cid=fsbdev2_038413 for some possibilities.
Thanks! There seem to be 3 varieties. One as the first picture that I attached, then there are ones with two yellow dots, and a 3rd with wings. I attached another picture of a dead one with the two yellow dots. They seem to be anywhere from 2mm-7mm in length. The ones with wings are longer, because of their wings.
Last summer, and this summer the tree has been dripping an excessive amount of runny sap(honey dew?). I also see quite a few ants, and pincer bugs in the tree, as well as some spiders. Last year the tree was swarming with yellow jackets, but I haven't seen them this year.
As for the ones with wings, they are probably not a different "variety". From Wikipedia: "When host plant quality becomes poor or conditions become crowded, some aphid species produce winged offspring, "alates", that can disperse to other food sources."
About all that I can add at this point is that they could be one of the giant conifer aphids (Cinara sp.) - http://www.whatsthatbug.com/2011/01/26/conifer-aphids/