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Gall Week 2022

9:00 AM

November 16, 2019

Online event


Join BioBlitz Club and gall lovers all around to celebrate the 2nd Gall Week event!

Fall is a great time to go on galling expeditions, when many species have fresh summer/ fall generation on different plant species. Join this global online event by observing and documenting galls from wherever you are! 

Gall Week events

  • Make observations between 9/3-9/11, and add them manually to our iNaturalist project Gall Week 2022
  • Webinar: Plant Galls for the Curious Naturalist - Wednesday 9/7, 5:30-6:30 pm. Info here.   
  • BioBlitz at Shady Oaks Park - Saturday 9/10, 9:00-11:00 - come document galls! Info here
  • Gall Walk at Little Uvas Open Space Preserve - Sunday, 9/11, 9:00-12:00. Info here

How to get started? 

You can look for specific host plants, specific groups of gall inducers, or anything you find interesting. If you've never done this before, you can check what are the best host plants in your area. You can use gall or insect books from your area, websites (such as, and iNat. We highly recommend listening to an interview of gall expert Adam Kranz on the podcast Natures Archive, and a shorter episode about Gall Week 2021. You can also look at our Gall Week 2021 progect, with over 6,500 observations from around the world! Another good way to start is to look at one of the gall projects and see what other people found in your area:

You can download fliers for some of the common Bay Area galls on our main page here. 

By The Numbers

View On iNaturalist








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