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Abstract
Black walnut has only a handful of insects that would be considered significant pests. Of the leaf feeders, the walnut caterpillar is the most likely to cause significant defoliation and damage to trees. However, severe infestations are infrequent and tend to be restricted to small geographic areas. Two other commonly encountered defoliators are the yellow necked caterpillar and the fall webworm. The black walnut curculio is the major nut pest on black walnut. The walnut shoot moth attacks buds and shoots of black walnut. Destruction of the terminal bud or shoot on young trees can cause excessive branch forking that can change the shape of a tree. Walnut does have several wood boring insects that will invade the main trunk and larger branches. Most of them infest trees that are in poor health. Many can also invade freshly cut logs. An ambrosia beetle,
Xylosandrus germanus, can attack apparently healthy trees and attacks are often associated with the pathogen
Fusarium. Management practices are provided that should minimize insect caused impacts.
Parent Publication
Citation
Katovich, Steven. 2004. Insects attacking black walnut in the midwestern United States. In: Michler, C.H.; Pijut, P.M.; Van Sambeek, J.W.; Coggeshall, M.V.; Seifert, J.; Woeste, K.; Overton, R.; Ponder, F., Jr., eds. Proceedings of the 6th Walnut Council Research Symposium; Gen. Tech. Rep. NC-243. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Research Station. 121-126
