Corn rootworms that can resist Bacillus thuriengensis (BT) carried in corn hybrids are multiplying and damaging crops in parts of Ontario, reports the Canadian Corn Pest Coalition.
Fields in Huron, Perth and Durham counties planted to Bt-containing hybrids have been damaged this year and the coalition said this is an early warning that resistance may be developing.
It suggests farmers scout their fields so they can prepare for next year’s planting decisions.
The risks are greatest on fields that have been in continuous corn production.
Resistance is already widespread in many parts of the United States.
