Of historical interest…

Past reports from the 1992 and 1967 WI DNR Forest Health Annual Reports

25 years ago – 1992

European fruit lecanium (Parthenolecanium corni (Bouche))

Heavy infestations of this scale insect were reported on sugar maple twigs in Vilas and Price counties.

Jack pine budworm (Choristoneura pinus (Rohwer))         

The outbreak in the northwestern counties, which began in 1991, exploded this year (Figure 16). Over 114,000 acres of jack pine were heavily defoliated in Douglas, Bayfield, Washburn and Burnett counties. Egg mass surveys indicate extremely high numbers of jack pine budworm. The area of defoliation may increase in 1993. The present defoliation is not expected to cause significant mortality except in Highland Township, but another year of heavy defoliation in the same stands could cause 10-15 percent mortality. In Highland Township, Douglas County, extremely severe feeding produced significant. mortality and top dieback on several thousand acres of jack pine. Most of these stands are being harvested this winter. Moderate to heavy defoliation also occurred in Jackson, Juneau, Eau Claire, Marinette (1,650 acres), Vilas (2,960 acres) and Oconto counties. In Marinette County, 20 acres of 70-year-old jack pine were cut to release young jack pine and white pine. Jack pine budworm was causing severe top mortality. Evidence of budworm in the northern portion of the Monroe County Forest was observed on 35-40 year old jack pine (Sections 4, 9,16, T19N, R3W). DNR foresters have silvicultural guidelines available to manage budworm-prone jack pine stands.”

50 years ago – 1967

Two-lined chestnut borer (Agrilus bilineatus (Weber))

Northeast Area – Oak mortality continued around the periphery of an area where jack oak (Quercus ellipsoidalis E. J. Hill) has been dying in southeast Menominee County for the past several years. The location, which involved parts of Sections 2, 9, 10, 11, 12, 13 and 14 of T28N, R16E, has repeatedly been defoliated to varying degrees by walkingsticks in odd-numbered years. Affected trees showed evidence of attack by borers, presumably two-lined chestnut borers. Mortality of scrub oak, which involved the chestnut borer, occurred in another location in Section 6, T28N, Rl6E. Red oak did not appear to be affected in this recently logged section.

West Central area – Although oaks continued to die in places where tree mortality followed attacks by the chestnut borer, loss of trees was much less than in 1966. Most of the damage occurred to inferior jack oak on poor sites. Many dying trees were observed in southwestern Wood County and northern Adams County.

East Central area – The borer was most prevalent in Marquette and Green Lake Counties in red and black oaks which were reduced in vigor by unfavorable growing conditions. Older trees showed evidence of previous borer attacks which were severe enough to reduce the value of logs which appeared sound externally.

Jack pine budworm (Choristoneura pinus (Freeman))

Northwest area – As predicted in 1966 budworm populations erupted in a majority of jack pine stands in the area. Moderate to complete defoliation occurred on about 80,000 acres (gross area) of jack-pine-type causing considerable top killing and tree mortality. Areas of severe defoliation were primarily in eastern Burnett County, northern Washburn County and parts of Douglas and Bayfield Counties. One small area of jack pine in Sawyer County (T42N, R9W) was severely defoliated in 1967. This area consisted mostly of plantations which had no known past history of budworm. Populations continued to decline in the Town of Sterling in Polk County and in western Burnett County where most of the mature and overmature trees have been cut leaving apparently young vigorous stands. These will be observed closely in future years to see if this type of silvicultural operation is successful in reducing the frequency of budworm population buildups. Pupal collections and egg mass surveys were made during July and August in all the jack pine type. Egg parasitism was very low in most areas and egg counts the highest of any year since these annual surveys have been conducted. Populations are expected to drop due to insufficient suitable feeding areas where stands have been severely defoliated. Populations are expected to be extremely high in stands which were near areas of heavy defoliation in 1967, but which were spared by the budworm then.

Northeast area – Heavy infestations of jack-pine budworm occurred near Conover (Sections 16, 17, 22, 23, 28, 29, T42N, R10E) and Boulder Junction (Sections 20, 21, 28, 29, T42N, R7E) in Vilas County, covering 1,120 and 1,600 acres respectively. Tree mortality followed the first year of near complete defoliation of timber near Conover in 1966 and added mortality followed 1967 defoliation. Heavy defoliation occurred for the first year on jack-pine near Boulder Junction. Over-mature stands, patches of over-mature trees in younger stands, and open grown large-crowned trees were affected first in both localities. Tree mortality occurred in a plantation near Conover and egg counts indicated that populations would be high again in 1968. Egg counts near Boulder Junction were about half those in the Conover area, but high populations are expected again in 1968. Light to moderate infestations occurred in Marinette (Section 19, T32N, R19E), Menominee (Sections 10, 11, 12, T28N, R16E) and Oconto (Section 30, T30N, R18E) counties.

West Central area – Budworm populations increased in jack pine stands throughout the area, but subsequent browning of trees was scattered. Heaviest populations and noticeable defoliation were found in Armenia Township in northeast Juneau County and Monroe Township in northwest Adams County. Egg Surveys indicated that defoliation may be more severe in Adams, Jackson, Juneau and Wood County stands during 1968.”


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