Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension

Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous > Lilac > Dead or dying branches

Print Icon Email Icon Share Icon

Lilac > Stems/branches > Dead or dying branches

1 of 3
  • lilacborer1
  • lilacborer2
  • lilacborer3

Lilac Borer (also known as ash borer)
Podosesia syringae

  • Wilted or dead stems
  • Base of stem swollen with ¼ inch exit holes
  • Sap, sawdust and frass exuding from holes
  • Reddish-brown pupa cases sometimes found protruding from exit holes
  • Larvae are 1' long; creamy white with light brown head
  • Adult is a clear wing moth that resembles paper wasp; smoky brown forewing, hindwing is clear with brown edge.
  • More information on Lilac borer
2 of 3
  • witchesbroom1
  • witchesbroom2
  • witchesbroom3

Witches' Broom
Candidatus Phytoplasma fraxini

  • Dense clusters of short, thin twigs originate from one area of stem
  • Leaves may be small, distorted and yellow
  • Brooms are common at the ends of branches and clustered at the very base of the plant
  • Entire canopy is pale green to yellow, some leaves with brown margins
  • Branches may die and shrub will decline
  • More information on Witches' Broom
3 of 3
  • verticilliumwilt1
  • verticilliumwilt2

Verticillium wilt
Verticillium dahlia

  • Leaves on one to several branches turn red to yellow, wilt, die and fall off
  • Dark olive to gray streaks are often visible in the sapwood if the bark is peeled back
  • The entire canopy may show symptoms in a single season or take several years
  • Symptoms are often most obvious in late summer and autumn but can occur throughout the growing season
  • More information on Verticillium wilt

Don't see what you're looking for?