Fields all across the Prairies are reporting aster yellows. The phytoplasma infection causes misshapen pods and flower buds. Infection looks awful and stands out, but rarely causes economical loss. Most fields don’t go above 1% infection rates. However, some fields are reported this year with rates at 5% to 8% of plants infected. This would be similar to 2007, which had Prairie canola fields at 5% to 20% infection.
A 10% infection rate results in 3% to 7% misshapen or missing seeds.
Note that plants infected with aster yellows can have misshapen seeds and yield loss without showing any of the obvious signs of infection — such as the puffed bladder-like pods. The plant looks normal but some pods are empty or contain misshapen seeds.
Aster yellows phytoplasma is carried by aster leafhoppers, which come up each year on south winds from the U.S. Canola varieties are not known to have any difference in infection rates. If aster yellows is found in one variety, it will be found in all varieties.