KITCHENER -- Gypsy moth caterpillar infestations are causing many people to have an allergic reaction and leaving them with rashes. Louise McGinn's yard has been taken over by the invasive species. "We have them all over our yard," she said. "We have a four-acre property and I would say at least 50 per cent of the trees are completely infested with them." McGinn said an allergic reaction has left her feeling sick, with itchy skin, for several days. "They were little pustules and they had a little puss inside them," she said. The Nature Conservancy of Canada said southern Ontario has had a bad infestation year for gypsy moth caterpillars.