Butternut (Juglans cinerea) - plot 22

306 seedlings were planted in 1978, in a strip along the edge of the ridge on plowed land. The CRF project was cancelled the following year, so many seedlings were lost to weed competition. Fewer than 100 survive. Almost all show severe infection with the butternut canker fungus (Sirococcus clavigigninti) that appeared in North America in the mid 60's. The trees are of too poor form to close their canopy, so the dead and dying butternuts were covered with wild grape (Vitis riparia) and cucumber (Echinocystis lobata) vines when examined in the fall of 2000. There were many young root sprouts (some may be from seed) - all were being dragged to the ground by the vines. The fungus is known to be spread with nut husks and wood, but its rate of spread indicates that at least one wide-ranging carrier for the spores exists - probably flying insects. It is considered useless to count on isolation of a tree to protect against infection - instead fungus resistance must be developed within the butternut genome by selection or hybridization. The vines have been removed, to ensure that the trees' growth is limited only by the canker. The plantation will be used as a test plot for natural seeds from trees that are believed to show some resistance to canker. This will take time - non-infection or successful containment of the canker is not considered reliable until the tree has reached 25 cm DBH or so. Any that survive the canker exposure here will be well worth studying further. John Sankey

The plantation as found, everything covered with vines The black smut of early butternut canker