North Central Research Station

Pine Shoot Beetle Outbreaks

The pine shoot beetle, Tomicus piniperda, is a major pest of pines in Europe and Asia.  It was first discovered in Ohio in 1992, and as of January 1999, it had spread to 243 counties in nine US states and 22 counties in Ontario, Canada.   1999 2000 2001 2002   The current US distribution can be found at the National Agricultural Pest Information System (NAPIS) web site.

In 1992, the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) imposed a federal quarantine on the movement of pine logs, pine Christmas trees, and pine nursery stock from Tomicus-infested counties to uninfested counties within the US.

The biology of Tomicus piniperda is incorporated into the specific requirements of the quarantine.  However, some requirements (i.e., the starting and ending dates for the unrestricted movement of logs during summer), use a single date for the entire infested area.  This approach was reasonable during the first few years after the discovery of Tomicus piniperda given its limited range, but as the beetle continued to spread it was realized that considerable climatic variation occurs within the infested region.  Therefore, we developed "phenological maps" that would help predict two major life-history events of Tomicus piniperda:  (1) the timing of initial adult flight in spring and (2) the timing of initial shoot departure in fall.

Over the past few years we have noted that the first strong burst of spring flight requires at least two consecutive days with maximum temperatures of 55°F or greater.  Initial spring flight for some of our native pine bark beetles, such as Ips pini, appears to require daily maximum temperatures closer to 70°F.  We developed isopleth maps indicating the average calendar date in spring when daily maximum temperatures first reached or exceeded various thresholds on two consecutive days.

The 55°F and 60°F maps will give the best indication of when initial spring flight of Tomicus piniperda will begin, but of course wide year-to-year variation can occur.   70° threshold 65° threshold 60° threshold 55° threshold 50° threshold

Similarly, in response to colder temperatures in the fall, Tomicus piniperda adults move from inside the shoots of pine trees where they feed during the summer, to the lower trunks of pine trees where they spend the winter.  Initiation of shoot departure in fall usually follows shortly after the first few hard freezes.  We developed isopleth maps for the second occurrence of when the average daily minimum temperature first reached various thresholds.

For predicting initial shoot departure of Tomicus piniperda, we feel that the 28°F map gives the best results.   32° threshold 28° threshold 24° threshold

For more information:

• Therese Poland  Project Leader rwu4501, Research Entomologist
• Bob Haack  Research Entomologist
• Warren E Heilman  Project Leader rwu4401, Research Meteorologist