By Linda Williams, DNR Forest Health Specialist, Woodruff; Linda.Williams@wisconsin.gov or 920-360-0665

Pip galls are small, tongue-like protrusions emerging from under the caps of acorns. / Photo Credit: Linda Williams, Wisconsin DNR.
Gall wasp life cycles can be complex. Did you know that acorn pip galls, which I’ve written about several times, have another part of their life cycle that is entirely different? This stage is called the woolly catkin gall.
Both woolly catkin galls and acorn pip galls are caused by Callirhytis quercusoperator, a species of cynipid gall wasp. This gall wasp takes two years to complete development by going through the two parts of its life cycle. Both parts of the life cycle are completed on northern red oak in our area.
Continue reading “Acorn Pip Galls, Woolly Catkin Galls All The Same”




You may have participated in this survey led by DNR Urban Forestry Coordinator Don Kissinger in 2020 (if so, thank you!) Wisconsin municipalities with more than 2,500 residents were asked a series of questions about the types of trees they prefer to plant (such as root stock type and caliper size), which lesser-used species they had successfully planted, which species they cannot find but would like to plant, and whether they use a gravel bed.

