Illinois Title Bar.
The Resource
Illinois forests have many recreation and wildlife benefits. In addition, over 37,000 people are employed in primary and secondary wood processing and manufacturing. The net volume of growing stock has increased by 40 percent since 1962, a reversal of the trend from 1948 to 1962. The volume of elms has continued to decrease due to Dutch elm disease, but red and white oaks, along with black walnut, have increased by 38 to 54 percent since 1962.

Illinois Major Forest Types.
Special Issues
Eastern tent caterpillar - Many Illinois counties experienced moderate to heavy defoliation of black cherry trees during April and May. Crabapple and apple trees were also attacked. Growers should consider control measures during early April if many tiny web nests are noted. Black cherry readily refoliates after complete defoliation but the annual growth is slowed by the defoliation.

Photo of Eastern Tent Caterpillar Webs. Map of Eastern Tent Caterpillar Infestation.

Bagworm - Moderate to heavy infestations of bagworm occurred mostly in central Illinois counties. Spruce, white pine, juniper, and arborvitae plants are the common hosts. Complete defoliation of evergreens results in tree death. This insect is more commonly found in urban landscapes although Christmas plantations containing spruce and white pine are vulnerable. Badly damaged trees are not saleable and damaged ornamental trees are unsightly. Control is best accomplished with an insecticide application in mid June after all the overwintering eggs have hatched.

Photo of Bagworm Tree Damage. Map showing Bagworm presence.

Pine Shoot Beetle - In 1992 the beetle was found in northeastern Illinois Will and Kane Counties. Since then the beetle has spread to the south and west and at present 30 Illinois counties are now infested. Since the first detection in Illinois owners of pine plantations have been informed that the removal of all dead and dying pines, slash, and the treatment of stumps are important practices to lessen the impact of this beetle. Populations of this beetle have remained low and if growers follow the outlined practices the species should remain at low levels.

Photo of Pine Shoot Beetle Tree Damage. Areas Infested With Pine Shoot Beetle.

Leaf Tatters - White oak species and hackberry have developed a leaf condition in the spring months called leaf tatters. For approximately the last 12 years trees in certain areas of Illinois have been affected. In some areas with severe conditions there is no development of leaf tissues between the major leaf veins. The first spring flush of leaves is affected, but the second late spring flush develops normally. The cause remains unknown but herbicide drift from agricultural fields is suspect. Trees severely affected may be weakened. It is advisable to water affected trees during drought conditions to lessen stress.

Photo showing Leaf Tatters Damage. Map of Leaf Tatters Spread.

Gypsy Moth - The first gypsy moths caught in Illinois occurred in 1973 when 5 moths were captured in pheromone traps set in northern Illinois. Since 1973 there was a gradual increase in the number of moth catches with a peak occurring in the early 1980's and then a decrease until the mid 1990's when numbers again started to increase. The decrease in numbers in the 1980's can be attributed to the use of Bacillus thuringiensis (Bt) sprays applied just after egg hatch in May. However in the 1990's with heavy infestations in some of the northern adjacent states and the increase of tourism and trade in these areas the numbers of moth catches started an increase in the 1990's and continues to the present. Infestations are becoming more numerous especially in the northeastern counties. The Illinois Department of Agriculture (IDA) in cooperation with USDA APHIS PPQ and the Forest Service have had a very successful suppression program. Now with many more areas of the northeastern counties becoming infested, the program of containment has been changed to a program of slowing the spread. In the northeastern counties the use of Bt sprays and pheromone flake applications will be used to slow the spread of the moth with continued moth trapping to monitor the spread.

Gypsy Moth Caterpillar. Map of Gypsy Moth Catches.

Asian Longhorned Beetle - In the summer of 1998 personnel of the Illinois Department of Agriculture reported infested Norway maple trees in the Ravenswood area of Chicago. The IDA Photo of Asian Longhorned cooperation with federal and Chicago municipal departments immediately began a thorough inspection of trees and where infested trees were located, quarantine areas were established. The Chicago newspapers, TV, and radio stations did a superb job in informing the public about the seriousness of the problem and requesting the public help in locating beetles and infested trees. Trucks with aerial lift buckets and tree climbers were used to inspect the bark surfaces of all trees in the quarantine areas. Any trees found to be infested were cut to ground level in the winter months and the wood burned. Thousands of trees were cut and destroyed in 1999 and 2000. Trees less susceptible to beetle attack were planted to replace the cut trees. In 2000 and 2001 some remaining trees in the quarantine areas, which appeared to be uninfested, were nevertheless treated with systemic insecticide trunk injections. In 2001 only two beetles were found in Chicago. The beetle continues to pose as a very serious threat to urban and forest trees but with the continuance of the present program this insect may be contained.

For more information contact:
Mike Mason
Division of Forest Resources
IL Dept. of Natural Resources
524 South Second Street
Lincoln Tower Plaza
Springfield, IL 62701-1787
Illinois DNR Logo. Forest Health Protection
Northeastern Area,
State & Private Forestry
USDA Forest Service
1992 Folwell Avenue
St. Paul, MN 55108
Northeastern Area Logo.
Updated: December 2001