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Figure 1: Chinese tallow invasion in Louisiana. Photo by Veronica Manrique.
The Chinese tallow (Triadica sebifera) is one the worst invasive trees in Louisiana. Originally from Asia, the Chinese tallow was introduced in the United States in the 1700s and is now present across the southeastern United States (Figure 1). The invasion of tallow has resulted in increased control costs and loss of revenue to foresters and natural resource managers. Current control methods, which include mechanical removal and herbicide applications, are considered ineffective for long-term control. To address this issue, the U.S. Department of Agriculture is developing a biological control program for tallow.
Biological control is the use of host-specific insects to reduce the growth and reproduction of target weeds resulting in decreased populations over time. After years of intensive research quarantine testing for insects that feed exclusively on tallow trees, two insects will be released in the United States for control of tallow. One is the beetle Bikasha collaris. Adult Bikasha collaris beetles feed on tallow leaves (Figure 2), and their larvae feed on tallow roots. The other insect to be released for tallow control is the nolid moth Gadirtha fusca. Nolid moth larvae are aggressive tallow defoliators (Figure 3). Previous studies showed that these two insects control tallow saplings and stress large trees. Once approved for release in Louisiana, efforts will be made to make this new tool available to land managers. Studies are underway to collect pre-release data on tallow demography, identify release sites and prepare for insect rearing in Louisiana. For more information about the Tallow Biological Control Program, please visit: www.lsuagcenter.com/chinesetallow.
Chinese tallow with beetle-damaged leaves.
Rodrigo Diaz is an assistant professor in the LSU AgCenter Department of Entomology.
Veronica Manrique is an assistant professor in the Southern University Department of Urban Forestry and Natural Resources.
Gregory Wheeler is a research entomologist for the U.S. Department of Agriculture Research Service.
