WINNIPEG -- Canada's pesticide regulator said on Wednesday that farmers could continue using the chemical imidacloprid to control crop-destroying insects under stricter conditions, softening an earlier proposal to ban it.

The chemical, made by Germany's Bayer AG, is part of the neonicotinoid class of pesticides that farmers have sprayed on crops since the 1990s. Farmers use imidacloprid to protect apples, potatoes and other fruits and vegetables from aphids and beetles.

Environmental groups have long said neonics harm beneficial aquatic insects when the chemicals accumulate in ponds and rivers. Those bugs are food for birds and fish.

The Pest Management Regulatory Agency (PMRA) proposed in 2016 phasing out imidacloprid due to those risks, before extending a feedback period.

Now in a statement with its final ruling, the agency said that such risks are acceptable within certain limits, after receiving public feedback and considering new water-monitoring data.

Farmers must reduce their application rates and not spray within buffer zones around sensitive areas, it said. Uses in certain situations are banned.

Canada imposed other restrictions to protect bees in 2019.

PMRA said in March it would also limit the use of two other types of crop chemicals, clothianidin and thiamethoxam, which have been linked to deaths of aquatic insects.

The European Commission banned outdoor use of all three neonicotinoids in 2018 to protect honeybees, although some countries have granted emergency authorizations. The U.S. Environmental Protection Agency is reviewing the chemicals' use.

Bayer has two years to update its Canadian product labels with new application instructions. A Bayer representative did not immediately respond to a request for comment.