Watermark disease affects infected trees by occluding the xylem vessels, impeding circulation.
Early signs of the disease are wilting or dried-out, dead leaves on intermittent branches throughout the tree's crown.
Cross sections from affected branches show a watery, transparent discoloration to an orange-brown staining in the wood.
Infected branches and trunks can be identified by red-brown staining in the sapwood that is restricted to the outer most rings.
An identifiable sign of the casual pathogen is oozing of Brenneria salicis from wounded, stained wood.
[citation needed] Like many bacterial pathogens, Brenneria salicis is naturally dispersed in air and water.
[citation needed] After emerging from its latent phase, branches will wilt and turn reddish-brown as the bacteria colonize the xylem.
Laws in certain communities that use willow commercially for cricket bats require the removal of infected trees.
Breeding for resistance is not a control method that is employed due to the limited incidence and impact of watermark disease.