European Corn Borer (ECB) Resistance to Bt in Atlantic Canada
Jun 14European Corn Borer (ECB) Resistance to Bt in Atlantic Canada
Atlantic Canada has the unenviable honor to be the first location in North America to report cases of ECB resistance to Bt in corn. In the 2018 season there were two confirmed cases in Nova Scotia and a few suspect, but unconfirmed cases in neighboring provinces.
There were resistant populations found for the Bt trait Cry1f. The high level of protein for Cry1Ab Bt trait was effective but as the plant matures the levels drop. Later in the season this Bt trait will be less effective with some populations as well.
The recommendations going forward are that growers should not plant single trait Bt hybrids for ECB containing only Cry1f (Herculex 1 and Herculex Xtra) or Cry1Ab (some Agrisure). It is also important for growers to note the diminished strength of stacked hybrids with two traits for ECB where one of them is Cry1f. Please refer to the table for available traits: https://www.cornpest.ca/bt-corn/bt-corn-products-traits-available-in-can...
It should be noted there are two other traits (Cry1A.105 and Cry2Ab2) that provide effective ECB control. Maizex hybrids, for sale in Atlantic Canada, generally include the VT Double Pro package which includes these two modes of action (Cry1A.105 and Cry2Ab2). Other traits listed on the chart (Vip3A, mCry3A, Cry34/Cry35Ab1) control other pests but not ECB.
In 2019 there will be extensive monitoring to determine the prevalence of this resistance challenge. Growers are encouraged to monitor their fields closely. If you notice significant damage beyond the refuge component, please contact your seed company representative or provincial specialist.