Who we are. What we do. Clemson University The Department of Plant Industry, a part of Regulatory Services in Clemson University’s Walnut Twig Beetle, Public Service and Agriculture, helps prevent the introduction of new plant pests into South Thousand Cankers Carolina as well as the spread of existing plant pests to non-infested areas. Plant pest surveys, inspections, quarantines, control and eradication programs are among the What to do. tools used to safeguard the state’s agricultural and natural resources. If you suspect you have an exotic invasive pest We help horticultural businesses - such as or think you have an infestation, please contact nurseries, greenhouses, transplant growers the Clemson University Department of Plant and turf grass producers - as well as farmers, Industry or your local Clemson University agricultural industries and South Carolina Cooperative Extension Service office. consumers in shipping plant material intrastate, For more information on invasive species, visit interstate and internationally. our website or find us on social media. Inspections and certification services help ensure that plants are pest-free, which is essential for movement of plant material to other states and foreign countries. Department of Plant Industry 511 Westinghouse Rd. Pendleton SC 29670 Phone: 864-646-2140 www.clemson.edu/invasives www.clemson.edu/invasives Eastern black walnut. A devastating disease. Black walnut (Juglans nigra) is an essential Walnut twig beetle carries component of Southeastern forests and spores of the fungus provides an ecological as well as economic Geosmithia morbida on its benefit to South Carolina. The dark wood is wing covers. The fungus popular in crafting furniture, and the walnuts then spreads from the make tasty treats. tunnels throughout the wood of the walnut as a The native range of black walnuts does not canker. extend into the Lowcountry, but they are During an infestation, planted in residential landscapes throughout beetles introduce the the state, especially in older neighborhoods. fungus numerous times, Characterized by their dark, deeply furrowed producing thousands of cankers. These cankers bark, black walnuts have large compound eventually girdle the tree’s nutrient-transporting leaves with 15-23 leaflets. They have tissues, starving it of numerous male catkins and terminal female nutrients. The complex, flowers that ripen into round, semifleshy fruit known as thousand cankers that contain the sought-after nut. disease, leads to crown dieback, yellowing of the Close to home. An unassuming beetle. upper leaves, the wilting of leaves and dark amber Unlike most of our regulated invasive pests, Pityophthorus juglandis, the walnut stains along branches and the walnut twig beetle is believed to be native twig beetle is hard to spot; at less stems. Thousand cankers to the US. The beetle was first recorded in than 2 mm in length, the adult disease ultimately results Arizona, and feeds harmlessly on the Arizona is smaller than a grain of rice. in the death of the black walnut. However, the beetle soon jumped The tiny, yellowish-brown beetle walnut. hosts to the black walnut planted in the West belongs to the Scolytidae family where researchers first described thousand and is one of the few beetles in the Inspect to protect. cankers disease. In 2010, both the beetle and Pityophthorus genus that feeds on DPI field staff place the disease were found in the native range of hardwood tree species. Lindgren funnel traps black walnut. Since then, regulators have made The adult beetles typically tunnel in wooded areas likely positive identifications of this invasive disease into branches larger than two centimeters in to harbor walnut twig complex in 4 Eastern states: Pennsylvania, diameter and overwinter in the bark cavities. beetles in order to Virginia, Tennessee and North Carolina. Infested branches are covered detect if it is present in Walnut twig beetle is a great example of how in tiny pin-sized holes bored South Carolina. Field a domestic pest can become invasive when by beetles. The larvae feed staff also inspect any introduced to new areas. Moving host material underneath the bark of the declining black walnuts across regions of the US can be just as risky as walnut tree and then emerge for thousand canker foreign trade. as adults in the early summer. disease..