BEETLE - MANIA IS A NE WSLETTER ON BIOLOGICAL CONTROL OF SALTCEDAR IN , AND IS WRITTEN AND PRODUCED BY ALLEN KNUTSON , TEXAS A&M AGRILIFE EXTENSION. TO BE INCLUDED ON THE MAILING LIST, PLEASE CONTACT ALLEN KNUTSON. BEETLE - MANIA BIOLOGICAL CONTROL OF SALTCEDAR IN TEXAS

VOL. 4 NO. 2 SUMMER - F A L L 2 0 1 2

2012. 2012. A A Very Very Good Good Year Year for for : TamariskSaltcedar Leaf Leaf Beetles Beetles in in Texas Texas ! ! The saltcedar leaf beetle feeds only on During 2012, saltcedar leaf seem to favor increase of river miles. However, follow- beetle populations increased saltcedar leaf beetles. If the ing the prolonged freeze, of saltcedar and athel. and dispersed at many loca- winter of 2012-2013 is again February 2011, none were Athel is a closely tions across the state and mild, leaf beetles should re- found and this species is now related species that more saltcedar trees were turn in force next year. believed to be absent from this grows along the Rio defoliated than ever before. There are now three spe- region. A second species, the After the early February cies of leaf beetle established subtropical leaf beetle Grande River in 2011 freeze, beetle popula- in Texas; the Uzbek beetle in (Tunisian) was released at five Texas. tions were low or absent at the Panhandle, the Mediterra- sites on the in many sites last summer. nean (Crete) leaf beetle on 2010-2011 and quickly estab- However, the mild winter of the Upper , lished and increased. During If saltcedar or 2011-2012 favored survival of and the subtropical leaf beetle 2012, this species, originally athel trees are not overwintering beetles. This (Tunisian) on the Pecos and collected from Tunisia, defoliat- present, the larvae was followed by an early Rivers. ed large acreages of saltcedar starve to death. spring and dry summer which along the Pecos River and allowed beetle numbers to Rio Grande, Pecos Rivers. adjacent areas (see map). further increase and disperse. The Mediterranean leaf bee- The subtropical tamarisk Saltcedar beetles Although the 2011 record tle, originally imported from beetles was also released on were first estab- drought took a heavy toll on Crete, was released on the the Rio Grande River during farms, ranches and water Pecos River in 2006 and defo- 2009-2010 and rapidly in- lished in Texas in supplies, these dry conditions liated saltcedar trees along 11 creased and dispersed. During 2004 at Big Spring, the past two years, this species TX. Since then, has defoliated almost all of the there have been no saltcedar along the Rio Grande River from Big Bend National reports of beetles or Park upriver to Candelaria, larvae feeding on where the road ends. Beetles any other plant. apparently continued to move upriver during 2012, through except saltcedar the “Forgotten River” section, and its close relative until mid-August when a ranch- athel (Tamarix er reported beetles on the river at Indian Hot Springs in aphylla). Hudspeth County. By October, beetles were defoliating saltce- dar trees within 40 miles of El Paso.

Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin. SUMMER - FALL 2012 PAGE 2 Beetles on the Rio Grande, Pecos, Colorado, Brazos, Red and Canadian Rivers.

Colorado and Concho. Large populations of the Mediterranean leaf beetle defoliated extensive stands of Larvae of the saltcedar stretching along Sulphur Springs saltcedar leaf Draw in Martin County and also at Lake Thomas. Beetles also defoliated saltcedar beetle feed on along the Colorado River in Mitchell Coun- ty. However, this species has been slow to saltcedar leaves recover in Howard County. Small popula- tions were present at Lake Spence and Lake and tender bark. Ivie but disappeared following the February Larvae feed for 2011 freeze. Overall, the Mediterranean has not increased or dispersed as rapidly as about 12-14 days has the two other species in Texas. Large numbers of the subtropical tamarisk beetle during the have been released at Lake Ivie and Lake Spence during 2011-2012, but are not yet summer. Full established. grown larvae are Brazos and Red Rivers. about 1/3 inch Both the Mediterranean (Crete) and Uz- bek species, D. carinata, are present in this long. Several area. The Uzbek beetle, originally collected generations are from Uzbekistan, defoliated miles of saltce- dar along the Pease River in Motely County completed per while the Mediterranean species defoliated trees along most of the in year. The adult King County, saltcedar infestations on Lake and along the Double stage overwinters Mountain Fork of the n south- on the ground ern Garza County. A few beetles were found at sites in Knox, Stonewall, and as far under leaf litter west as Lynn County. These are early “pioneer” beetles that disperse far and and in clump wide from established populations. grasses.

Canadian and Red Rivers. The most surprising event in 2012 was the discovery of the Uzbek beetle in the Texas Panhandle and its rapid spread. This species was released at several sites during 2005-2009, but was not seen again until 2012 when it suddenly defoliated large areas of saltcedar on the Prairie Dog Town Fork of the Red River, the Red River and the . Surveys by Texas AgriLife Research found D. carinata in Hutchinson, Roberts, Hemphill, Gray, Wheeler, Armstrong, Donely, Collingsworth, Childress, Randal, Cottle, Motley, Briscoe and Hall counties. Tom Royer at Oklahoma State University reported beetles defoliating trees in adjacent Oklahoma.

B E E T L E - MANIA VOL. 4 NO. 2 P A G E 3

Saltcedar: Seed Production, Dispersal and Survival Seeds and Seed Production. Drought and Floods Favor New voirs with enough water that much of The invasive ability of saltcedar is due in Infestations. Both flooding and the area recently invaded by saltcedar part to its high reproductive rate and drought favor new infestations of salt- will be under water long enough to ability to disperse seeds by water and cedar. As an example, saltcedar has drown the saltcedars. air. Saltcedar trees flower and produce quickly invaded the mud flats exposed seeds throughout the growing season if at Lake Ivie as water levels have sharply Reference: Ecology and Management of Saltcedar. USDA- soil moisture is adequate. A medium declined there due to the 2011 and on- NRCS Invasive Species Technical Note No. MT-13. 2007. sized tree can produce up to 600,000 going drought. On the other extreme, seeds while a large tree can yield up to heavy rains in 2010 flooded the Lower 10 million seeds or more per year. The Rio Grande Valley Wildlife Refuge, kill- seeds are extremely small (0.02-0.04 ing native vegetation submerged under inch long) and contained within a cap- 12-25 ft of water. Saltcedar seedling, sule. A tuft of hairs allows the seed to carried on the wind and flood waters, float on the wind and water and seeds quickly germinated and grew rapidly in are therefor carried long distances. the wet soil with no competition from Seeds remain viable for up to 45 days other vegetation. Saltcedar thickets are under ideal summer conditions or up to now a major concern over some 18,000 130 days during the winter. Once seeds acres of refuge land. come into contact with moisture, they Tolerance to Inundation. Ac- germinate in about 24 hours. The wet cording to USDA-NRCS (see citation) soil that appears along the margins of seedling saltcedars can withstand total lakes and reservoirs as the water level inundation by water for up to four Saltcedar Seed. Seeds are declines and areas drying out from weeks. Mature trees can survive up to about 0.02 to 0.04 inch long floods can be quickly invaded by saltce- 98 days of total inundation. Hopefully, USDA PLANTS Database, USDA NRCS dar seedlings. rains will return and begin to fill reser- PLANTS Database, Bugwood.org Distribution of Saltcedar Leaf Beetles in the US.

The Tamarisk Coalition is a re- gional non-profit organization in Grand Junction, CO working to help people restore riverside habi- tats in the American West with a focus on invasive plant species. The Tamarisk Coalition recently com- pleted this map showing how the Northern Tamarisk leaf beetle, D. carinulata, has dispersed through Nevada, Utah and Colorado during 2007-2012 and then into New Mexico in 2010. The map also shows the distribution of the three beetle species in Texas in 2012 and the movement of the Uzbek beetle into western Oklaho- ma. Thanks to Jesse Lanci and the Tamarisk Coalition for providing this map. For more information on the TC, go to: http://www.tamariskcoalition.org

For more information about this program, BEETLE-MANIA is a newsletter on biological control of saltcedar in Texas, and is written contact Allen Knutson at 972-952-9222 or via e and produced by Allen Knutson, Texas A&M -mail [email protected] or Mark Muegge AgriLife Extension. To be included on the mailing list, please contact Allen Knutson. Texas AgriLife Extension Entomologist at Ft. Stockton, 432-336-8585, , e-mail: ma-muegge Allen Knutson Professor and Extension Entomologist @tamu.edu Texas AgriLife Research and Extension

17360 Coit Road Dallas, TX 75252

Phone: 972-952-9222 For more information on biological control of saltcedar and other Fax: 972-952-9632 invasive weeds in Texas, go on-line E-mail: [email protected] at: bc4weeds.tamu.edu.