In northern Stearns County,on the southwest corner of Birch Lake State Forest, walkingsticks (Diapheromera femorata) have heavily defoliated about 200 acres of oaks, other hardwoods and the shrubs below them. Their slender and wingless bodies, long and thin legs, long antennae, dull green to brown bodies and their habit of remaining motionless, make then resemble sticks, hence the name. By August 30th, most walkingsticks had grown to their adult size of 2½ to 3½ inches and were mating. Walkingstick eggs were dropped onto the forest floor, sometimes sounding like the patter of rain. Over l00 eggs per square foot of ground have been counted in previous infestations. Fortunately, almost all of these eggs will remain dormant until the spring of 2001, thereby allowing trees to regain vigor in the year of 2000. Low populations of this insect have also been observed in southern Sherburne, southeastern Cass, northeastern Morrison, and west central Crow Wing Counties. No noticeable defoliation of oaks or other hardwoods or shrubs occurred in these locations.
Only a few orangestriped oakworms, Anisota senatoria, ¼ to 1¼ inch long remained as defoliators of bur oaks in central Minnesota by September 1st . They were found in Todd County about two miles east of Little Sauk along county road # 6. In l997 and l998, this forest insect had heavily defoliated the oaks, but a buildup of parasites of eggs and caterpillars was observed in l998. On August 30th this year, about 20% of the caterpillars were parasitized or diseased. Some were diseased when they were ½ inch long, some weeks ago, and the dead and shriveled caterpillars were still attached to leaves. Why this Todd County oakworm population lagged so far behind those in nearby Morrison, Benton, and Crow Wing Counties is a mystery. Very little defoliation by the orangestriped oakworm in the Little Sauk area is predicted for 2000.
At several other locations in central and northwestern Minnesota this forest insect and pinkstriped oakworms, Anisota virgeniensis, had heavily defoliated oaks and transformed into pupae by late July.