Plant Galls of Alaska

Dominique Collet

Galls are plant tissues modified by another organism

Gall-inducing Organisms

• Nematodes • Fungi • Bacteria • Plant • Algae • Acarina (mites) • Insects

Galled organisms

Algae Fungi

Lichens

Flowering plants

Gall Types

Plant tissue growth inhibited : Leaf rolls Rosette galls Willow beaked galls Cottonwood petiole galls • New plant tissue stimulated • Rose spiny galls • Some stem galls

Common Alaskan Plants Affected by Galls

Achillea sp. Cecidomyiidae Arctostaphyllos uva-ursi Tamalia coweni (Aphididae) Betula Massalongia spp., Oligotrophus spp., (Cecidomyiidae) Calamagrostis canadensis Mayetiola sp. (Cecidomyiidae) Epilobium angustifolium Mompha sp. (Momphidae) Picea glauca: Adelges spp., Pineus spp. (Adelgidae) Populus trichocarpa Pemphigus sp. (Eriosomatidae)

Eriophiidae Rosa spp. Diplolepis spp. (Cynipidae) Salix spp. Rabdophaga spp., Iteomyia spp.(Cecidomyiidae) Euura spp., Pontania spp., Phyllocolpa spp. (Tenthredinidae) Eriophiidae

Galling arthropods

• Eriophyiid mites (pouch galls) • Sawflies: stem galls (Euura), leaf

margin roll (Phyllocolpa), leaf galls (Pontania)

• Cecidomyiidae: stem galls, bud galls, petiole galls (Rabdophaga)

• Aphids: petiole galls (Adelges, Pemphigus)

Plant Organ Galled

• Leaf buds • Stem • Flower buds- fruits- seeds • Roots

Tortricidae leaf roll on birch

Tamalia coweni leaf margin roll on Arctostaphyllos uva-ursi

Phyllocolpa sp. leaf margin roll on Salix alaxensis

Eriophiid mites induced leaf curling on Populus balsamiferous

Epilobium angustifolium stem gall induced by Mompha sp.

Mompha sp. caterpillars inside the gall

Calamagrostis canadensis and Arctagrostis latifolia inflorescences galled by Mayetiola spp. (Cecidomyiidae)

Diplolepis polita and its spiny galls on Rosa acicularis

Revision in progress of the taxonomy of Euura, Phyllocolpa and Pontania of Alaska by Dr. Jens Peter Kopelke of the Senckenberg Institute in Frankfurt, Germany.

Euura sp. Pontania spp.- induced galls on willow

Cross-section showing the location of gall-inducer larva chambers

Larva in a single chamber Single empty

chamber

Rabdophaga rosaria and R. strobiloides galls

Multiple chambers

S. sitchensis S. pulchra S. bebbiana

S. barclayi

S. glauca

S. richardsonii

S. barclayi

S. commutata

S. fuscescens

S. myrtillifolia S. pulchra

S. bebbiana

S. babylonica S. sitchensis

Rabdophaga specimens inducing rosettes on these willows are included in a comparative DNA study with similar Japanese and European specimens by Dr. Junici Yukawa and Shinsuke Sato at the University of Kyushu, Fukuoka, Japan

Rabdophaga rigidae galls on Salix

S. glauca

S. alaxensis

S. myrtillifolia S. fuscescens

S. barclayi

S. bebbiana

S. pulchra

Galls useful for the winter identification of Alaskan willows

S. pulchra

S. bebbiana S. arbusculoides

S. barclayi

S. sitchensis

S. glauca