Aster Yellows is a bacterial disease that is spread by an insect carrying the bacteria. 

Which Insect Carries Aster Yellows?

The Aster Leaf Hopper is a small insect that arrives in Western Canada upon winds blowing in from the US during early spring. They usually appear in small numbers and are not a significant problem in this area, besides in 2012 when the County had an abnormal infestation.

The symptoms of the disease usually become visible at podding time and are very noticeable in canola crops. There are no effective control methods for the leaf hopper.

What to Look For

Aster Yellows damage        aster Yellow Hopper             Aster Yellow Hopper

       Aster Yellow Damage                           Adult Leaf Hopper                                   Adult Leaf Hopper


Because the Aster Leaf Hopper is small and hard to detect in the early stages of a crop, it's almost always missed when crop scouting. The few steps that can be taken to prevent or control this pest are mainly cultural:

  • Keep fields clean and weed free to eliminate establishment of host plants
  • Seeding crops early may mean that crops are more mature and less attractive during      the time when Leaf Hoppers are most actively causing damage

Related Links

Alberta Government Aster Yellows Information

Canola Watch Aster Yellows Q & A