MARY W. OLSEN
Extension Plant Pathologist Department of Plant Pathology

DEBORAH J. YOUNG
Extension Plant Pathologist

Pathogen
Several different bacteria and yeasts

Host
Mesquite, cottonwood, ash, elm, mulberry, willow, poplar, apple, firs, maples, pine, sycamore, and other trees

At a Glance

• Prevent Slime Flux using good cultural prac­tices, particularly good distribution of irrigation water and proper pruning.
  
• Most trees with Slime Flux will live for many years.
  

Symptoms/signs

A dark, watery exudate drains from branch crotches, cracks, pruning cuts and other wounds. This liquid often runs down the branches and trunk or may drip from infection sites. Branches may die back in severely affected trees. The liquid that seeps out of affected tissue may support growth of many other microorganisms which gives it the slimy texture and may cause an offensive odor that is associated with the disease. The liquid may also attract insects.

Environmental conditions

Disease is found throughout Arizona, differing in cli­matic zones only in the tree hosts in which it occurs.

Disease

Slime flux is caused by the infection of sapwood by several different bacteria. Yeasts may also be involved in the disease. The microorganisms that have been associated with disease are commonly found in soils and probably enter through wounds above and below the soil line. Over a period of time, which may be several years, the number of microorganisms increases in the wood, causing the water-soaked symptoms of wetwood. Large amounts of gases may be produced as the microorganisms grow, and the liquid is forced out of cracks and wounds.

Prevention/control

There are no preventative methods for Slime Flux except good tree health care practices, proper watering, feeding and pruning. There are no controls for the disease. The practice of installing tubes to drain liquid is no longer recommended since it does not alleviate the problem and the holes are a good infection site for many pathogenic organisms. Trees with Slime Flux will usually live for many years, but any weakened limb should be removed if it is a safety risk. If the dripping causes stains on patios or walkways, a hard water spray, applied routinely, will prevent staining.