1000 Cankers Disease - Ask Extension
Are there any new developments for treating black walnut tress suffering from 1000 cankers disease in 2013?Two years ago I treated the roots in early ...
Knowledgebase
1000 Cankers Disease #141786
Asked July 19, 2013, 1:51 PM EDT
Are there any new developments for treating black walnut tress suffering from 1000 cankers disease in 2013?
Two years ago I treated the roots in early Spring with about 5 gallons of diluted imidacloprid (a Merit product) and the tree looked very healthy that season. I did not treat the next season and the tree looked well for the majority of the season but weak by September. I treated similarly this year with the imidacloprid solution, but my tree has not responded and looks very stressed. Canopy is thin with appearance of a few dead branches on lower part of tree. No appearance of yellowing or darkening of bark on main trunk.
Can I treat with injected insecticide at some point between now and the next growing season and have a likelihood of seeing improvement? If so, when should I treat and with what and how much?
Two years ago I treated the roots in early Spring with about 5 gallons of diluted imidacloprid (a Merit product) and the tree looked very healthy that season. I did not treat the next season and the tree looked well for the majority of the season but weak by September. I treated similarly this year with the imidacloprid solution, but my tree has not responded and looks very stressed. Canopy is thin with appearance of a few dead branches on lower part of tree. No appearance of yellowing or darkening of bark on main trunk.
Can I treat with injected insecticide at some point between now and the next growing season and have a likelihood of seeing improvement? If so, when should I treat and with what and how much?
Denver County Colorado
Expert Response
1,000 cankers is a newly recognized
disease of Walnut trees caused by a
canker-producing fungus (Geosmithia morbida) vectored by a bark beetle (Walnut
Twig Beetle – Pityophthorus juglandis). There is no effective means
to control the disease. The best tactic is to “Slow the Spread” - survey, detection, & removal. Detection –
survey for flagging (yellowing of branches) on Walnut trees July & Aug. For more information, visit the CSU Dept of Bioagricultural Sciences & Pest Management bspm.agsci.colostate.edu (under “Outreach” tab)
and the National Site
(USDA, Walnut Council, Purdue, etc) thousandcankers.com
