CS-34 CURRENT SERIAL RECORDS April 1965 
TREAT STUMPS TO PREVENT FOMES ANNOSUS IN 
SHORTLEAF PINE PLANTATIONS 
Fomes annosus (Fr.) Cke. is a fungus that causes a seri- 
ous root and butt rot of pines and other conifers throughout 
the world. All of our native conifers are probably suscepti- 
ble so the many old-field plantations in the Central States 
and elsewhere are threatened. 
F. annosus frequently becomes established when a healthy 
stand is thinned. Airborne spores of the fungus are deposit- 
ed on freshly cut stump surfaces. After spores germinate, 
the fungus grows down the stump, out along the roots, to the 
roots of healthy trees that are in contact. More and more 
trees become diseased as the infection center gradually en- 
larges. The average growth rate of the fungus in the roots 
is about 3 feet a year so mortality from F. annosus does not 
show up until 2 or 3 years after thinning. Once tree roots 
become infected, the fungus may survive below ground for 50 
years or more. The fungus can also live for many years as a 
saprophyte on dead trees, stumps, and cull logs of certain 
hardwoods as well as conifers. 
Since most infection appears to begin at freshly cut 
stumps, here would seem to be a good place to employ some 
sort of chemical treatment for control. 
THE STUDY 
In 1962 and 1963 we investigated the effectiveness of a 
number of chemicals in preventing colonization of pine stumps 
by F. annosus in a 26-year-old shortleaf pine plantation on 
the Clark National Forest in southern Missouri. Sample trees 
used in the experiment were cut about 20 inches above the 
