Press Herald cites Kirby, Smart in article about plant pests and cold weather

The Portland Press Herald spoke with Clay Kirby and Alcyn Smart for an article about the recent below-zero temperatures effect on plant pests. Kirby, a pest management specialist at the University of Maine Cooperative Extension, said that many pests live in a layer of fallen leaves and twigs below the snow and ice. According to Kirby, the temperature of this layer, insulated by the overlying snow, can be much warmer than the sub-zero air temperatures above. “The snow can be considered insulation for them,” said Kirby, and as a result, ticks and other soil-living pests will probably not be impacted by the recent cold snap in any significant way. The temperatures effect on plant diseases is much less. Smart, a UMaine Extension plant pathologist, said that the cold will likely have no effect on pathogens whatsoever. “Basically, if the plant is still living, then the pathogen is still living,” said Smart. The fungi that cause many plant diseases create a protective web that helps guard against the cold temperatures, and soil-borne pathogens are protected beneath the soil and the insulating layer of snow. Not all pests, however, were impervious to the extreme cold. The article states that populations of both the invasive gypsy and winter moth, as well as the hemlock woolly adelgid, may have been reduced due to the cold.