Jack pine budworm gains a toe-hold

map of jack pine budworm defoliation in 2003

It's been several years since the last jack pine budworm outbreak in Minnesota and, frankly, this outbreak was way overdue. Since 1954, outbreaks in western counties have occurred been four to seven years apart. The last JPBW outbreak ended in 1994, making it a whopping nine years since budworms were active here.

In 2002 and 2003, spring weather was warm and dry and the pollen cone crops were heavy in Beltrami County which allowed the budworm larvae an excellent opportunity for building up their populations. This year, a Bemidji Area forester noted a telltale sign of budworm feeding, namely, no clouds of jack pine pollen although the pollen cones were very abundant.

We have four hot-spots in the state, from Roseau County reaching down to Sherburne County. See map and table.

Location

Acres Defoliated

Roseau Co.

114

Bemidji and SW

16,807

Brainerd and West

1478

Sherburne Co.

147

Total

18546

Budworm populations and activity are expected to increase and intensify in at least the three northern locations and "spread out" to stands between Bemidji and Brainerd. In fact, some of these stands already had a slight tinge of defoliation this year. And, factoring in the hot, dry summer weather, it's a good bet that we'll see defoliated jack pine stands in Cass, Wadena, Hubbard, Becker and Clearwater Counties next year. In Sherburne County, budworms have defoliated a few red pine stands. Read the following article to learn more about it.