Thousand cankers disease (TCD) is a caused by a combination of a fungus (Geosmithia morbida) and the walnut twig beetle (Pityophthorus juglandis). The walnut twig beetles carries fungal spores, and when they tunnel through the outer bark into the tree the fungus is transmitted during gallery construction. This has also been found if the beetle “tastes” the tree and does not produce a gallery. The fungus kills an area under the bark and the areas of dead tissue are called cankers. When the walnut twig beetles are abundant, numerous cankers can form and coalesce to girdle twigs and branches, restricting movement of water and nutrients. Black walnut (Juglans nigra), the most valuable native species to the state, is the most susceptible of the Juglans species to this disease.
Asian Longhorned Beetle (ALB) feeds on a wide variety of hardwood tree species that are native or planted in Kansas. It kills trees by creating large tunnels as larvae causing branches or stems to break and eventually lead to tree death. Because this beetle is not native to North America, it has no known natural enemies, and our trees have low resistance to this pest. It has not been detected in Kansas. It has been stated that if the ALB were to become established in the US, it could become one of the most destructive and costly pests ever to industry, urban neighborhoods, and natural forests.
In 1869, the European gypsy moth was introduced to North America by Professor E.L. Trouvelot in an attempt to breed a hardy silkworm. Some insects escaped and were soon established in a vacant lot next to his home in Medford, Mass. Since then, it has been infested the northeast, resulting in massive defoliation of shade, fruit, and ornamental trees as well as hardwood forests. Caterpillars devour the leaves of many hardwood tree species and shrubs that can turn a usually lush summer scene into one of winter. Estimates up to 13 million acres of trees have been defoliated in one season, damaging local ecosystems and killing trees after repeated attacks.
Asian Gypsy Moth is a native of Asia and was first detected in Washington in 1991. Ongoing and completed eradication of various sites in the U.S. have so far prevented the establishment of this generalist feeder. This moth is much more destructive if it became established and spread east because of its broad host range and the females are active fliers due to their larger wingspan.