Entomology (Study of Bugs)/Bugs? on Peonies


Peonie Leaves
Peonie Leaves  

Peonie Stalks
Peonie Stalks  
Sauggy, we need your help again.
As the end of the growing season approached we started to get what appeared to be a mold on our peonies. It happens so we didn't think much about it. When we were cutting them down we noticed little bumps going up the stalks. We can't tell if they are bugs or just a naturally occurring part of the plant. Any ideas?

Dear Tom - Your peony leaves appear to have a powdery mildew infection - see http://tinyurl.com/knjgnqr for detailed information including control recommendations. The 'bumps' on the stem are armored scale insects (Hemiptera/Sternorrhyncha: Diaspididae); like aphids, they feed on the sap of the plants they infest. Plants usually can tolerate a light infestation, but if the scales are very abundant, they may cause leaf yellowing, wilting and premature leaf drop. Also, a heavily infested peony plant may grow slowly and suffer dieback. In cases of heavy infestation, pruning off and disposing of infested portions (such as by burning) or applying a thorough spray of horticultural oil in late winter to spring should control these pests.

Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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