GreatPlants names 2008 selections

Nebraska Nursery & Landscape Association and Nebraska Statewide Arboretum announced its 2008 GreatPlants selections. The program also is celebrating its 10th year of marketing plants proven to perform in the Great Plains. The program’s 2008 recommendations are: • Tree of the year: Ostrya virginiana, American hophornbeam, is a medium-sized tree with heart-shaped leaves that turn yellow in fall. • Conifer: Pinus bungeana, lacebark pine, is a good alternative to Scotch pine. Its attractive bark features a patchwork of white, green and purple. • Shrub: Euonymus atropurpurea, Eastern wahoo, grows well in full sun or shade. It reaches 12 feet high. • Perennial: Geum triflorum, prairie smoke, features purple-red flowers in early spring and feathery silver and pink seedheads. • Ornamental grass: Bouteloua gracilis, blue grama, forms low mats of curly, narrow leaves that measure 6 inches long. Seedheads grow 18 inches tall in July and last all winter. GreatPlants also announced its 2008 releases, which are all drought tolerant: • Populus tremuloides ‘NeArb’ Prairie Gold quaking aspen is a fast-growing selection resistant to canker, leaf spot and borers. • Quercus prinoides, dwarf chinkapin oak, grows 15 feet tall and wide in full sun. Dianthus ‘Wink’ features evergreen foliage and pink flowers from midspring to early summer. ◆ For more: Nebraska Statewide Arboretum, (402) 472-7923; http://arboretum.unl.edu/greatplants/.

Parasites successfully infect, destroy fire ant mounds

Two protozoan parasites are showing promise in the fight against imported fire ants. On the heels of the successful release of phorid flies to control fire ants, USDA’s Agricultural Research Service is testing Thelohania solenopsae and Vairimorpha invictae. The parasites live in their host’s cells and infect the mound. Worker ants transfer T. solenopsae spores to the queen, possibly through food. Infection reduces the queen’s egg laying, so colonies die out. “Though we found that natural field infections of T. solenopsae were more prevalent in fire ant colonies with several queens, we also confirmed that single-queen colonies were susceptible to infection,” said ARS entomologist David Oi.

V. invictae successfully destroyed fire ant mounds, and researchers proved the parasite doesn’t infect non-fire ants or other arthropods. “This is important because it shows that this pathogen may also be suitable for release in the United States with little or no risk,” Oi said. ARS researchers also discovered the first virus known to infect red imported fire ants — Solenopsis invicta virus-1. It’s been associated with the deaths of immature ants. Infected ants don’t usually show symptoms unless they encounter certain stressors. Then, viral replication increases within them, and their brood later dies.

◆ For more: David Oi, ARS, (352) 374-5987; david.oi@ars.usda.gov.