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Approved for public release; distribution is unlimited. ERDC/TN APCRP-BC-39 September 2017 Surveys for Biological Control Agents of Hydrilla verticillata and Myriophyllum spicatum in the Republic of Korea and the People’s Republic of China in 2014 by Matthew Purcell1, Nathan E. Harms2, Michael J. Grodowitz2, Jialiang Zhang3, Myung-Hyuun Kim4, Kwang-Jin Cho4, Young J. Oh5, Sun-Hee Hong6, and Jianqing Ding3 PURPOSE: The purpose of this Technical Note (TN) is to summarize overseas work conducted in 2014 to locate insect biological control agents of dioecious and monoecious Hydrilla verticillata (L.f.) Royle (hydrilla) and Myriophyllum spicatum L. (Eurasian Water Milfoil) (EWM) in the Republic of Korea (RK) and the People’s Republic of China (PRC). This work includes surveys of hydrilla and EWM sites in the RK and the PRC, and represents ongoing efforts towards identifying previously collected and reared agents. INTRODUCTION: Hydrilla is a submersed invasive plant that is native to Africa, Asia, Australia, and parts of Europe; it has been present in the United States since the 1950s (Buckingham and Grodowitz 2004; Schmitz et al. 1991). Two genetically and ecologically distinct hydrilla biotypes are currently recognized in the U.S.; a pistillate dioecious biotype which is generally found in the southeastern and south central region and a monoecious biotype which mostly occurs in the central Atlantic and northeastern regions. (Madeira et al. 2000). Though the dioecious biotype has been present in the U.S. for over sixty years, monoecious hydrilla is widely recognized as a more recent introduction. Monoecious hydrilla was first discovered in the northeastern region of the U.S. in 1976 (Steward et al. 1984) and since then it has been reported in Alabama, California, Connecticut, Delaware, Georgia, Indiana, Kansas, Kentucky, Maine, Massachusetts, Maryland, Missouri, North Carolina, New Jersey, New York, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia, Washington, Wes

ERDC/EL TR-17-3 Aquatic Plant Control Research Program Surveys for Biological Control Agents of Hydrilla verticillata in the People’s Republic of China in 2013 Environmental Laboratory Nathan E. Harms, Matthew Purcell, Jialiang Zhang, Michael J. Grodowitz, and Jianqing Ding March 2017 Approved for public release; distribution is unlimited. The US Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and environmental challenges. ERDC develops innovative solutions in civil and military engineering, geospatial sciences, water resources, and environmental sciences for the Army, the Department of Defense, civilian agencies, and our nation’s public good. Find out more at www.erdc.usace.army.mil. To search for other technical reports published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. Aquatic Plant Control Research Program ERDC/EL TR-17-3 March 2017 Surveys for Biological Control Agents of Hydrilla verticillata in the People’s Republic of China in 2013 Nathan E. Harms and Michael Grodowitz Environmental Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Matthew Purcell USDA-ARS, Australian Biological Control Laboratory (ABCL) 41 Boggo Road, Dutton Park Queensland, Australia 4102 Jialiang Zhang and Jianqing Ding Invasion Biology and Biocontrol Lab Wuhan Botanical Institute Chinese Academy of Sciences Wuhan, Hubei Province, 430074 China Final report Approved for public release; distribution is unlimited. Prepared for U.S. Army Corps of Engineers Washington, DC 20314-1000 Under Project number 96X3122 ERDC/EL TR-17-3 ii Abstract This report summarizes the result of 2013 surveys in the People’s Republic of China of the invasive aquatic weed Hydrilla verticillata for potential insect biological control agents. Plants were examined at 34 sites throughout eastern China, resulting in the collection of leaf-mining Hydrellia spp. (Diptera: Ephyd

Approved for public release; distribution is unlimited. ERDC/TN APCRP-BC-41 July 2017 The Influence of Fluctuating Temperature on Megamelus scutellaris Berg (Hemiptera: Delphacidae) by Michael J. Grodowitz, Nathan E. Harms, and Jan E. Freedman PURPOSE: Information from unpublished reports, field, and greenhouse observations suggests that temperatures exceeding 29° C can cause reduced development and increased mortality of Megamelus scutellaris Berg (waterhyacinth planthopper), a biological control agent released for the management of Eichhornia crassipes (Mart. Solms). This document reports the results of an experiment conducted under greenhouse conditions designed to gauge temperature impacts to M. scutellaris survival and reproduction under fluctuating temperatures regimes. BACKGROUND: Waterhyacinth (E. crassipes) was first introduced into the U.S. in Louisiana during the International Cotton Exposition in 1884 (Center 2004). Since its initial introduction, the range of waterhyacinth has spread to include the southern and western regions of the United States and is expanding northward (U.S. Department of Agriculture/Natural Resources Conservation Service [USDA/NRCS] 2016). Waterhyacinth is capable of rapid growth and can quickly cover the water’s surface thereby reducing light penetration to algae and submersed plants, lowering dissolved oxygen levels and pH, and ultimately leading to altered native species diversity (Getsinger et al. 2014; Center 2004; Villamagna and Murphy 2009). Mats of waterhyacinth have also been shown to obstruct waterways, impact irrigation and drinking water delivery, navigation, and recreation. Additionally, waterhyacinth has been documented as a human health hazard by increasing mosquito breeding habitats (Center 2004). Four insect biological control agents have been released in the U.S. for the management of waterhyacinth (Tipping et al. 2014a; Center et al. 2004; Tipping et al. 2011) including two weevils (Neochetina eichhorniae Warner

This document summarizes the development of rearing techniques and methodology for field releases of Megamelus scutellaris Berg (Hemiptera: Delphacidae; waterhyacinth planthopper) during the period 2010-2012. This work was accomplished through a collaborative effort that involved the US Army Corps of Engineers - Engineer Research and Development Center (USACE-ERDC) and the Louisiana State University (LSU) AgCenter. Over 3 years of adaptive rearing techniques, more than 13,875 M. scutellaris were released at field sites in Texas and Louisiana. In addition, because of questions regarding temperature tolerance and related mortality of various life stages of M. scutellaris, a study was undertaken to examine temperature differences in key internal tissues of the waterhyacinth plant and within the canopy in relationship to changes in water temperature. To the authors knowledge, this is the first published information regarding the influence of water and air temperature on canopy and internal plant temperature in waterhyacinth.

Hydrilla verticillata L.f. Royle (hydrilla; Hydrocharitaceae), an invasive submersed plant native to Southeast Asia and Australia, was first introduced into the US through the aquarium trade in Florida in the 1950s (Schmitz et al. 1991). Hydrilla impacts freshwater resources in the US by its aggressive, canopy-forming growth that degrades aquatic ecosystems, limits recreation, fouls boat motors, and clogs irrigation and hydroelectric plants. In the US there are two recognized hydrilla biotypes: the dioecious biotype is generally found in the southeastern and south central US; whereas the monoecious biotype is mostly found in the central Atlantic and northeastern US (Madeira et al. 2000). The dioecious biotype has been present, and spreading, in the US since the first introduction over 50 years ago. In contrast, monoecious hydrilla is widely recognized as a relatively recent introduction, first identified in the northeastern United States in 1982 (Steward et al. 1984). Since the initial identification, monoecious hydrilla has been reported in Connecticut, Massachusetts, Maine, New York, and as far south as Georgia and Alabama. Additional populations of the monoecious biotype are known to be found in Washington and California (Madeira et al. 2000). Management of hydrilla is typically accomplished through mechanical, chemical, and biological means. Mechanical harvesting of hydrilla has been attempted over the years but it is typically cost prohibitive and results in production of additional plant propagules through fragmentation. Chemical applications include complexed copper, diquat, endothall, fluridone, and more recently imazamox, penoxsulam, bispyribac-sodium, and flumioxazin (Gallagher and Haller 1990, Netherland 2009).

Approved for public release; distribution is unlimited. ERDC/TN APCRP-BC-32 February 2014 Genetic Relationships among Invasive Hydrilla (Hydrilla verticillata L.f. Royle) Biotypes in the US and Their Implications for Management by Nathan E. Harms1, Dean A. Williams2, and Michael J. Grodowitz1 INTRODUCTION: Hydrilla verticillata L.f. Royle (hydrilla; Hydrocharitaceae), an invasive submersed plant native to Southeast Asia and Australia, was first introduced into the US through the aquarium trade in Florida in the 1950s (Schmitz et al. 1991). Hydrilla impacts freshwater resources in the US by its aggressive, canopy-forming growth that degrades aquatic ecosystems, limits recreation, fouls boat motors, and clogs irrigation and hydroelectric plants. In the US there are two recognized hydrilla biotypes: the dioecious biotype is generally found in the southeastern and south central US; whereas the monoecious biotype is mostly found in the central Atlantic and northeastern US (Madeira et al. 2000). The dioecious biotype has been present, and spreading, in the US since the first introduction over 50 years ago. In contrast, monoecious hydrilla is widely recognized as a relatively recent introduction, first identified in the northeastern United States in 1982 (Steward et al. 1984). Since the initial identification, monoecious hydrilla has been reported in Connecticut, Massachusetts, Maine, New York, and as far south as Georgia and Alabama. Additional populations of the monoecious biotype are known to be found in Washington and California (Madeira et al. 2000). Management of hydrilla is typically accomplished through mechanical, chemical, and biological means. Mechanical harvesting of hydrilla has been attempted over the years but it is typically cost prohibitive and results in production of additional plant propagules through fragmentation. Chemical applications include complexed copper, diquat, endothall, fluridone, and — more recently — imazamox, penoxsulam, bispyribac-sodium

Approved for public release; distribution is unlimited. ERDC/TN APCRP-BC-33 July 2014 The Use of Megamelus scutellaris Berg in the Southern United States as a Biocontrol Agent of Waterhyacinth (Eichhornia crassipes (Mart.)) by Michael J. Grodowitz,1 Seth Johnson,2 and Nathan E. Harms1 PURPOSE: This document summarizes the development of rearing techniques and methodology for field releases of Megamelus scutellaris Berg (Hemiptera: Delphacidae; waterhyacinth planthopper) during the period 2010-2012. This work was accomplished through a collaborative effort that involved the US Army Corps of Engineers - Engineer Research and Development Center (USACE-ERDC) and the Louisiana State University (LSU) AgCenter. Over 3 years of adaptive rearing techniques, more than 13,875 M. scutellaris were released at field sites in Texas and Louisiana. In addition, because of questions regarding temperature tolerance and related mortality of various life stages of M. scutellaris, a study was undertaken to examine temperature differences in key internal tissues of the waterhyacinth plant and within the canopy in relationship to changes in water temperature. To the authors’ knowledge, this is the first published information regarding the influence of water and air temperature on canopy and internal plant temperature in waterhyacinth. BACKGROUND: The floating invasive plant species waterhyacinth (Eichhornia crassipes Mart. Solms) was first introduced into the United States in Louisiana during the International Cotton Exposition (Center 2004) in 1884. Since its primary introduction, the adventive range of waterhyacinth has spread to include the southern and western United States and disjunct northern populations (US Department of Agriculture/Natural Resources Conservation Service (USDA/NRCS) 2012). Waterhyacinth is capable of rapid growth and can quickly cover the water surface to shade out water bodies, thus reducing light penetration to algae and submersed plants, thereby lowering dissolv