~Today’s blog is brought to you by Dwight Willoughby P. Ag, CCSC~
Right after swathing is the best time to find blackleg cankers in a field should the disease be present. A farm operation can the evaluate the degree of risk for that field and plan for the following years to manage blackleg.
Basal cankers, if present, are easy to see. Using clippers, clip the base of the stem at the top of the root. The plant tissue free of blackleg will have no black dead tissue. If blackleg is present, the ratings range from 0 to 5.
0 – No diseased tissue visible in the cross section.
1 – Diseased tissue occupies up to 25 % of the cross section.
2 – Diseased tissue occupies 26-50 % of the cross section.
3 – Diseased tissue occupies 51-75 % of the cross section.
4 – Diseased tissue occupies less than 75% of the cross section with little or no constriction of affected tissues.
5 – Diseased tissue occupies 100 % of the cross section with significant constriction of affected tissues; tissue dry and brittle; plant dead.
Rating scale above found on www.canolawatch.org