The spraying 20 years ago was effective in reducing the infestation to a manageable level and seemed to do so for quite a while. That is, until now. Merrill Brady told me last week that he is inundated with tent caterpillars this year. His property is down by the greenbelt lots and the caterpillars are stripping the 60-foot cottonwoods and all other vegetation of all of their leaves.

The tent caterpillar may be chewing its way through swathes of forest foliage, but there's no danger of harm to trees, says expert.

Tammi Hanowskirsquo's yard is carpeted in forest tent caterpillars.

Hordes of tent caterpillars have covered Tammi Hanowski's home south of Saskatoon and have crawled up the walls and made their way into her pool.