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Leaf galls

Various (Cynipidae, Cecidomyiidae, Eriophyidae, Psyllidae)

57 host plants

Last updated

Data Coverage 1 of 6 dimensions
Host Plants
GDD Threshold
Peak Activity
Damage Severity
Monitoring
Regional Notes

Oak trees develop various gall structures on leaves created by gall wasps, sawflies, and other gall-forming insects. These galls vary in appearance from small bumps to larger, multi-chambered structures; some are round, others spiky or irregular in shape. You notice the abnormal growths on foliage during spring and summer. Gall formation is primarily a cosmetic concern that does not seriously harm overall tree health.

Most leaf galls do not require control and are best viewed as part of normal oak ecology. Prune out heavily galled branches during dormancy if appearance is a concern. Rake and remove fallen galled leaves to reduce overwintering gall wasp populations. No chemical treatment is warranted since oaks tolerate galls and natural parasitoids regulate populations.

Quick Reference

Order
Various
Type
gall-former
Host Plants
57

Cultural Controls

  • Pick out and destroy galls when noticed (when practical).
  • Many galls mature in the fall, so gall removal and destruction prior to this may help reduce numbers of wasps in the spring.
  • Prune out unsightly galls to improve tree's appearance, when practical.

Host Plants (57)

Quercus acutissima Sawtooth Oak Quercus agrifolia Coast Live Oak Quercus alba (Eastern) White Oak Quercus arizonica Arizona Oak, Arizona White Oak Quercus berberidifolia California Scrub Oak, Scrub Oak, Inland Scrub Oak Quercus bicolor Swamp White Oak Quercus bimundorum Two Worlds Oak, Bimundors Oak Quercus castaneifolia Chestnut-leaved Oak, Chestnutleaf Oak, Persian Oak Quercus cerris Turkey Oak Quercus chrysolepis Canyon Live Oak Quercus coccinea Scarlet Oak Quercus douglasii Blue Oak, California Blue Oak Quercus durata Leather Oak Quercus emoryi Emory Oak, Black Oak, Blackjack Oak Quercus engelmannii Engelmann Oak, Mesa Oak Quercus frainetto Hungarian Oak, Italian Oak Quercus gambelii Gambel Oak, Rocky Mountain White Oak Quercus garryana Oregon White Oak Quercus garryana var. breweri Brewer's Oak Quercus glandulifera Konara Oak Quercus glauca Japanese Blue Oak, Ring-cupped Oak Quercus hypoleucoides Silverleaf Oak, Whiteleaf Oak Quercus ilex Holly, Oak, Holm Oak Quercus ilicifolia Bear Oak Quercus imbricaria Shingle Oak Quercus kelloggii California Black Oak Quercus leana Lea's Oak Quercus lobata Valley Oak, Roble Oak, California White Oak Quercus macrocarpa Bur Oak, Mossycup Oak Quercus marilandica Blackjack Oak, Jack Oak Quercus mongolica Mongolian Oak Quercus montana Mountain Chestnut, Oak, Chestnut, Oak, Rock Chestnust Oak Quercus muehlenbergii Chinkapin Oak, Chinquapin Oak, Yellow Chestnut, Oak Quercus myrsinifolia Chinese Evergreen Oak, Bamboo-leaf Oak Quercus nigra Water Oak, Possum Oak Quercus palustris Pin Oak, Swamp Spanish Oak Quercus petraea Sessile Oak, Durmast Oak, Irish Oak Quercus phellos Willow, Oak Quercus prinoides Dwarf Chinquapin Oak, Dwarf Chestnut, Oak, Scrub Chestnut, Oak Quercus robur English Oak Quercus rubra Northern Red Oak Quercus sadleriana Sadler Oak, Deer Oak Quercus stellata Post Oak Quercus suber Cork Oak Quercus turbinella Scrub Live Oak Quercus undulata Wavyleaved Oak Quercus vaccinifolia Huckleberry, Oak Quercus velutina Black Oak Quercus virginiana Southern Live Oak, Live Oak Quercus wislizeni Interior Live Oak, Chapparal Oak Tilia americana American Linden, American Basswood Tilia cordata Littleleaf Linden Tilia euchlora Crimean Linden Tilia europaea European Linden, Common Linden Common Lime European Basswood Tilia mongolica Mongolian Linden, Mongolian Basswood Tilia tomentosa Silver Linden, Silver Basswood Viburnum dilatatum Linden, Viburnum, Linden, Arrowwood