Corn seed treatment 'may' be connected to bee deaths: Health Canada

Tuesday, September 11, 2012

by BETTER FARMING STAFF

Pesticides used on treated corn seeds “may” have contributed to “at least some of the 2012 spring bee losses that occurred in Ontario,” Health Canada has told Better Farming via email.
The email, from Health Canada media relations officer Sara O’Dacre, says other factors are being considered and that “final conclusions” have not been made.

“Given the large number of potential factors involved, Health Canada, along with its provincial colleagues, is continuing to examine other factors, including overall bee health, agriculture practices and environmental conditions,” the email says.

In early summer, the federal Pest Management Regulatory Agency (PMRA) began a re-evaluation of a group of insecticides used to protect seeds and crops from insects because more than 100 incidents of acute poisoning symptoms were reported to the PMRA and the provincial environment and agriculture ministries. Most occurred in southwestern Ontario.

The products being re-evaluated are clothianidin, thiamethoxam and imidacloprid. They are all neonicotinoid insecticides, a class of insecticides that act on the central nervous system of insects and can kill bees.

Clothianidin is the active ingredient in Bayer CropScience’s Titan and in Poncho. Clothianidin is also in Valent’s Arena 50 WDG and Clutch 50 WDG. Thiamethoxam is one of the active ingredients in Syngenta’s CruiserMaxx. Imidacloprid is one of the active ingredients in Bayer’s Concept. The products are registered in Canada for use as seed treatments, foliar sprays, in-furrow applications and in greenhouses to control insects in fruits, vegetables and cash crops.

The re-evaluation covers these active ingredients and their associated products registered in Canada. Imidacloprid was already being re-evaluated when the agency announced the review of the other two, PMRA says.

In a study published in January, researchers from Purdue University in Indiana and the Connecticut Agricultural Experiment Station found neonicotinoid insecticides in bees that had died in or near hives in Indiana apiaries.

Further study by the researchers suggested that talc used to reduce stickiness of corn and soybean seeds treated with the insecticide might be to blame. The talc forms a fine, light dust during planting and can contain high levels of the insecticide. The researchers suggested that reducing or eliminating talc on the seeds could fix the problem. BF