{"id":2367,"date":"2014-01-16T12:37:00","date_gmt":"2014-01-16T12:37:00","guid":{"rendered":"http:\/\/www.blog.sdps-bbs.com\/?p=2367"},"modified":"2026-04-17T14:45:45","modified_gmt":"2026-04-17T18:45:45","slug":"cold-weather-and-emerald-ash-borer","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/fnr\/extension\/cold-weather-and-emerald-ash-borer\/","title":{"rendered":"Cold Weather And Emerald Ash Borer"},"content":{"rendered":"
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Since the Polar Vortex subsided, there has been quite a bit of buzz about the Emerald Ash Borer (EAB), an exotic beetle that is killing ash trees across Indiana and the U.S., being killed by the multi-day sub-zero temperatures we experienced here in Indiana and elsewhere. Some recent research (the full paper can be accessed USDA Forest Service, <\/span>Cold Hardiness of Emerald Ash Borer, Agrilus Planipennis<\/em>: A New Perspective<\/a>) predicts that when EAB larvae reach 0\u00b0F, 5% will die; at\u00a0-10\u00b0F, 34% will die; at\u00a0-20\u00b0F, 79% will die; and at\u00a0-30\u00b0F, 98% will die. Based on some -15\u00b0F temperatures here at the Purdue West Lafayette campus, we might expect around 50% of the EAB will die, but some additional points need to be considered.<\/span><\/p>\n

\"Emerald<\/a>

An adult emerald ash borer feeds off a leaf. (Purdue University Department of Entomology photo\/John Obermeyer)<\/p><\/div>\n

EAB larvae are located overwinter under the bark in infested ash trees, so the bark may offer some insulation. Snow is also an excellent insulator, so the lower trunk of ash trees\u00a0in deep snow or drifts may not get as cold as ambient air temperatures. Some trees in town or near structures may remain warmer due to heat radiating or escaping from buildings. The message is, unfortunately, that the cold weather we experienced was probably not enough to solve our EAB problems.<\/p>\n

It is good news that some of the population was probably killed by the cold weather, leaving fewer larvae to damage ash trees next spring. This will be a temporary setback for the borer, since one of the biological strengths of insects is their capacity to reproduce and grow populations quickly. Further north in places like Minnesota, the news for the ash trees may be better where temperatures below -30\u00b0F may have killed most of the larvae, providing some additional time to prepare for the EAB onslaught. Here in Indiana, we need to continue to monitor, prepare and act to limit the damage EAB will do.<\/p>\n

Some basic steps include:<\/p>\n