Host specificity of the leaf beetle, Diorhabda elongata deserticola (Coleoptera: Chrysomelidae) from Asia, a biological control agent for saltcedars (Tamarix: Tamaricaceae) in the Western United States

Abstract

Four species of saltcedars, Tamarix ramosissima Ledeb., Tamarix chinensis Lour., Tamarix parviflora DC., and T. canariensis Willd. and their hybrids, are exotic, invasive small trees from Asia that cause great damage to riparian ecosystems of the western United States. They displace native plant communities, degrade wildlife habitat (including that of many endangered species), increase soil salinity and wildfires, lower water tables, reduce water available for agriculture and municipalities, and reduce recreational use of affected areas. Phytophagous insects are abundant on saltcedar in the Old World and we selected Diorhabda elongata Brull e e deserticola Chen as the top candidate biological control agent because of the great damage it causes, and its high host specificity, broad geographic range, and presumed adaptability in the United States. Literature review and our overseas surveys indicated that this insect is associated only with species of Tamarix and occasionally with Myricaria but not with Reumaria or Frankenia (all Tamaricales) in the Old World. In quarantine facilities in the United States, and overseas, we tested beetles from China and Kazakhstan on six species and three hybrids (26 accessions) of Tamarix and on 58 species of other plants, in 15 tests of different types, using 1852 adults and 3547 larvae, over 10 years. Survival from larvae to adults averaged 55-67% on the Tamarix species, 12% on Myricaria sp., and only 1.6% on the three Frankenia spp. No larvae completed their development on any of the other 54 plant species tested, where most larvae died during the first instar. Adults oviposited readily on T. ramosissima accessions, less on Tamarix aphylla (L.) Karst. (athel), and only rarely on other plants. The host range of the D. e. deserticola we tested from Kazakhstan was not different from those we tested from China. Therefore, D. e. deserticola, is sufficiently host-specific and was approved for field release in North America. This is the first biological control agent introduced into the United States for control of saltcedar. Published by Elsevier Science (USA).

Relação Entre Tempo e Besouros em Mata de Cocal

“…Os crisomelídeos, como citam Deloach et al (2003), são majoritariamente herbívoros, se alimentam desde brió-fitas às gimnospermas e às angiospermas. De acordo com os mesmos autores, a maior parte é monófoga, no entanto há espécies polífagas e algumas são estudadas como agentes potenciais de controle biológico de ervas daninhas.…”

“…Os coleópteros, conhecidos popularmente como besouros, são indicadores importantes da qualidade do meio ambiente, devido à ocorrência em quantidade e diversidade de habitats que ocupam. Como explicam Doyen et al (1998), o sucesso desta ordem é atribuído principalmente à presença de élitros e aos diversos hábitos alimentares que suas espécies possuem.…”

Assessment of Tannin Variation in Tamarisk Foliage Across a Latitudinal Gradient

“…Thus, there is no evidence of a gradient in natural selection favoring higher tannin concentrations at one latitude versus another. Experiments on the beetle introduced to control tamarisk in North America (Diorhabda elongata) have demonstrated considerable variation among individual tamarisks in their quality as a food source for the beetles [12]. While these data suggest that tannin concentration may contribute to individual variation, tannins are likely not responsible for observed latitudinal effects.…”

Weed biological control in the European Union: from serendipity to strategy

“…The latter case of Diorhabda elongata (Brullé) is particularly interesting as this taxon was introduced into the USA in 1999 to control saltcedar (De Loach et al 2003), but turned out to be a group of five sibling species with different geographical origins ranging from the Mediterranean region to Asia (Tracy and Robbins 2009). Fortunately, all five chrysomelid species defoliate saltcedar populations in the southeastern USA and contributed to the successful control of these widespread invasive trees.…”