Tests to determine pesticides' ecological risks do not take into account protection of development and reproduction in plants, unlike tests required for the protection of animals, scientists from the Soil Science Society of America said in the Journal of Environmental Quality.

Their research found that even though vegetation may not display symptoms of injury, its reproductive organs may be severely damaged.

Specifically, potato tuber yield and quality were hurt by herbicides even at rates below those causing a reduction in vegetative growth or injury, the researchers said.

Tubers are the swollen, fleshy, underground potato stems bearing buds from which new plant shoots arise.

Besides having ecological consequences, the damage can reduce plant yield and quality, which could create "significant" economic losses, the scientists said.

Potato tuber formation may be a sensitive indicator of developmental and reproductive responses of plants to chemical pesticides, they said.