Diorhabda carinata
Encyclopedia
Diorhabda carinata is a species of leaf beetle
known as the larger tamarisk beetle (larger tamarisk beetle) which feeds on tamarisk trees from Ukraine, eastern Turkey and Syria east to northwest China, Kyrgyzstan and Pakistan, extending as far south as southern Iran. It is used in North America as a biological pest control
agent against saltcedar or tamarisk (Tamarix
spp.), an invasive species
in arid and semi-arid ecosystems (where the larger tamarisk beetle and its closely related sibling species
also may be less accurately referred to as the 'saltcedar beetle', 'saltcedar leaf beetle', 'salt cedar leaf beetle', or 'tamarisk leaf beetle').
). Weise created the genus Diorhabda in 1893 and proposed the color variant Diorhaba elongata var. carinata (Faldermann), and he also placed the sibling species Galeruca carinulata Desbrochers (the northern tamarisk beetle, Diorhabda carinulata
) as a junior synonym of this variant. Bechyné (1961) proposed the subspecies D. e. carinata listing specimens from Afghanistan. Berti and Rapillly (1973) recognized D. carinata and D. carinulata as separate species from one another, and, by implication, as separate species from D. elongata, based on detailed morphology of the endophallus of the male genitalia. Tracy and Robbins (2009) confirmed the 1973 findings of Berti and Rapilly, further characterized the male and female genitalia of D. carinata, and provided illustrated taxonomic keys separating the larger tamarisk beetle from the four other sibling species of the D. elongata (Brullé) species group: Diorhabda elongata
, Diorhabda sublineata
(Lucas), Diorhabda carinulata
, and Diorhabda meridionalis
Berti and Rapilly. In literature prior to 2009, D. carinata was usually also referred to as D. elongata, or subspecies of D. elongata.
. In laboratory and field cage studies, the larger tamarisk beetle will also feed and complete development on Frankenia shrubs of the family Frankeniaceae
, distant relatives of tamarisks in the same plant order Tamaricales
, but larger tamarisk beetle greatly prefer to lay eggs upon tamarisk.
, similar to that found in Diorhabda carinulata, that could serve to attract both males and females to certain tamarisk trees.
in west Texas in 2006. By 2008, the larger tamarisk beetle had defoliated about 0.2 hectares of tamarisk near Seymour, Texas. The larger tamarisk beetle may be better adapted to warm temperate grassland and desert habitats of west Texas than other Old World tamarisk beetles that are being introduced, such as the Mediterranean tamarisk beetle, Diorhabda elongata
. The northern tamarisk beetle, Diorhabda carinulata
, is probably better adapted to northern cold deserts in North America where it is widely established, and the subtropical tamarisk beetle, Diorhabda sublineata
, may be better adapted to subtropical deserts.
Tamarisk does not usually die from a single defoliation from tamarisk beetles, and it can resprout within several weeks of defoliation. Repeated defoliation of individual tamarisk trees can lead to severe dieback the next season and death of the tree within several years. Tamarisk beetle defoliation over the course of at least one to several years can severely reduce the nonstructural carbohydrate reserves in the root crowns of tamarisk. Biological control of tamarisk by the larger tamarisk beetle will not eradicate tamarisk but it has the potential to suppress tamarisk populations by 75–85%, after which both larger tamarisk beetle and tamarisk populations should reach equilibrium at lower levels.
A primary objective of tamarisk biological control with the larger tamarisk beetle is to reduce competition by exotic tamarisk with a variety of native riparian flora, including trees (willows, cottonwoods, and honey mesquite), shrubs (wolfberry, saltbush, and baccharis), and grasses (alkali sacaton, saltgrass, and vinemesquite). Unlike expensive chemical and mechanical controls of tamarisk that often must be repeated, tamarisk biological control does not harm native flora and is self-sustaining in the environment. Recovery of native riparian grasses can be quite rapid under the once closed canopy of repeatedly defoliated tamarisk. However, tamarisk beetle defoliation can locally reduce nesting habitat for riparian woodland birds until native woodland flora are able to return. In some areas, tamarisk may be replaced by grasslands or shrublands, resulting in losses of riparian forest habitats for birds (Tracy and DeLoach 1999). Releases of tamarisk beetles in southern California, Arizona, and along the Rio Grande in western New Mexico, are currently delayed until concerns can be resolved regarding safety of tamarisk biological control to nesting habitats of the federally endangered southwestern willow flycatcher, Empidonax traillii Audubon subspecies extimus Phillips, which will nest in tamarisk.
Leaf beetle
Beetles in the family Chrysomelidae are commonly known as leaf beetles. This is a family of over 35,000 species in more than 2,500 genera, one of the largest and most commonly encountered of all beetle families....
known as the larger tamarisk beetle (larger tamarisk beetle) which feeds on tamarisk trees from Ukraine, eastern Turkey and Syria east to northwest China, Kyrgyzstan and Pakistan, extending as far south as southern Iran. It is used in North America as a biological pest control
Biological pest control
Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...
agent against saltcedar or tamarisk (Tamarix
Tamarix
The genus Tamarix is composed of about 50-60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa...
spp.), an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in arid and semi-arid ecosystems (where the larger tamarisk beetle and its closely related sibling species
Sibling species
Sibling species are species that are very similar in appearance, in behavior and in other characteristics, but they are reproductively isolated. In other words, sibling species are pairs or groups of genetically closely related species which are often morphologically indistinguishable, but are...
also may be less accurately referred to as the 'saltcedar beetle', 'saltcedar leaf beetle', 'salt cedar leaf beetle', or 'tamarisk leaf beetle').
Taxonomy
The larger tamarisk beetle was first described from the Transcaucasus (Georgia and Azerbaijan) as Galeruca carinata Faldermann, 1837. Reiche and Saulcy placed G. carinata as a junior synonym to the sibling species G. elongata Brullé (the Mediterranean tamarisk beetle, Diorhabda elongataDiorhabda elongata
Diorhabda elongata is a species of leaf beetle known as the Mediterranean tamarisk beetle which feeds on tamarisk trees from Portugal and Algeria east to southern Russia...
). Weise created the genus Diorhabda in 1893 and proposed the color variant Diorhaba elongata var. carinata (Faldermann), and he also placed the sibling species Galeruca carinulata Desbrochers (the northern tamarisk beetle, Diorhabda carinulata
Diorhabda carinulata
Diorhabda carinulata is a species of leaf beetle known as the northern tamarisk beetle which feeds on tamarisk trees from southern Russia and Iran to Mongolia and western China...
) as a junior synonym of this variant. Bechyné (1961) proposed the subspecies D. e. carinata listing specimens from Afghanistan. Berti and Rapillly (1973) recognized D. carinata and D. carinulata as separate species from one another, and, by implication, as separate species from D. elongata, based on detailed morphology of the endophallus of the male genitalia. Tracy and Robbins (2009) confirmed the 1973 findings of Berti and Rapilly, further characterized the male and female genitalia of D. carinata, and provided illustrated taxonomic keys separating the larger tamarisk beetle from the four other sibling species of the D. elongata (Brullé) species group: Diorhabda elongata
Diorhabda elongata
Diorhabda elongata is a species of leaf beetle known as the Mediterranean tamarisk beetle which feeds on tamarisk trees from Portugal and Algeria east to southern Russia...
, Diorhabda sublineata
Diorhabda sublineata
Diorhabda sublineata is a species of leaf beetle known as the subtropical tamarisk beetle which feeds on tamarisk trees from Portugal, Spain and France to Morocco, Senegal, Algeria, Tunisia, Egypt, Yemen, and Iraq...
(Lucas), Diorhabda carinulata
Diorhabda carinulata
Diorhabda carinulata is a species of leaf beetle known as the northern tamarisk beetle which feeds on tamarisk trees from southern Russia and Iran to Mongolia and western China...
, and Diorhabda meridionalis
Diorhabda meridionalis
Diorhabda meridionalis is a species of leaf beetle known as the southern tamarisk beetle which feeds on tamarisk trees from Syria to western and southern Iran and southern Pakistan...
Berti and Rapilly. In literature prior to 2009, D. carinata was usually also referred to as D. elongata, or subspecies of D. elongata.
Host plants
Field collections in Eurasia reveal that the larger tamarisk beetle feeds on at least nine species of tamarisks, including Tamarix ramosissima which is widely invasive in western North America. The larger tamarisk beetle will severely defoliate tamarisk in Turkmenistan and Tajikistan. Extensive laboratory host range studies verified that larger tamarisk beetle is a specialist feeder on tamarisks, feeding only on plants of the tamarisk family, TamaricaceaeTamaricaceae
Tamaricaceae is a flowering plant family containing four genera. In the 1980s, the family was classified in the Violales under the Cronquist system; more modern classifications place them in the Caryophyllales.The family is native to drier areas of Europe, Asia and Africa...
. In laboratory and field cage studies, the larger tamarisk beetle will also feed and complete development on Frankenia shrubs of the family Frankeniaceae
Frankeniaceae
Frankeniaceae is the botanical name for a family of flowering plants. Such a family has been widely recognized by many taxonomists; it has commonly been assumed to be closely related to family Tamaricaceae....
, distant relatives of tamarisks in the same plant order Tamaricales
Tamaricales
The Tamaricales are an order of dicotyledons. This order has been abandoned by the most recent systems, and the three families in the order have been distributed to other orders:* family Tamaricaceae, now in the Caryophyllales;...
, but larger tamarisk beetle greatly prefer to lay eggs upon tamarisk.
Life cycle
The larger tamarisk beetle overwinters as adults on the ground. Adults become active and begin feeding and mating in the early spring when tamarisk leaves are budding. Eggs are laid on tamarisk leaves and bark and hatch in about a week in warm weather. Three larval stages feed on tamarisk leaves for about two and a half weeks when they crawl to the ground and spend about 5 days as a C-shaped inactive prepupa before pupating about one week. Adults emerge from pupae to complete the life cycle in about 4–5 weeks in the summer. Five generations of larger tamarisk beetle occur through spring and fall in central Texas. Similar to the northern tamarisk beetle, adults begin to enter diapause in the late summer and early fall, ceasing reproduction and feeding to build fat bodies before seeking a protected place to overwinter. Larvae and adults are sensitive to shorter daylengths as the summer progresses that signal the coming of winter and induce diapause. Robert Bartelt and Allard Cossé (USDA-ARS, Peoria, Illinois) found that male larger tamarisk beetle emit a putative aggregation pheromonePheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
, similar to that found in Diorhabda carinulata, that could serve to attract both males and females to certain tamarisk trees.
Biological control agent
The larger tamarisk beetle is currently weakley established as a biological control agent for tamarisk in west Texas. Populations of larger tamarisk beetle from around 39°N latitude near Qarshi, Uzbekistan were initially released by the USDA Agricultural Research ServiceAgricultural Research Service
The Agricultural Research Service is the principal in-house research agency of the United States Department of Agriculture . ARS is one of four agencies in USDA's Research, Education and Economics mission area...
in west Texas in 2006. By 2008, the larger tamarisk beetle had defoliated about 0.2 hectares of tamarisk near Seymour, Texas. The larger tamarisk beetle may be better adapted to warm temperate grassland and desert habitats of west Texas than other Old World tamarisk beetles that are being introduced, such as the Mediterranean tamarisk beetle, Diorhabda elongata
Diorhabda elongata
Diorhabda elongata is a species of leaf beetle known as the Mediterranean tamarisk beetle which feeds on tamarisk trees from Portugal and Algeria east to southern Russia...
. The northern tamarisk beetle, Diorhabda carinulata
Diorhabda carinulata
Diorhabda carinulata is a species of leaf beetle known as the northern tamarisk beetle which feeds on tamarisk trees from southern Russia and Iran to Mongolia and western China...
, is probably better adapted to northern cold deserts in North America where it is widely established, and the subtropical tamarisk beetle, Diorhabda sublineata
Diorhabda sublineata
Diorhabda sublineata is a species of leaf beetle known as the subtropical tamarisk beetle which feeds on tamarisk trees from Portugal, Spain and France to Morocco, Senegal, Algeria, Tunisia, Egypt, Yemen, and Iraq...
, may be better adapted to subtropical deserts.
Tamarisk does not usually die from a single defoliation from tamarisk beetles, and it can resprout within several weeks of defoliation. Repeated defoliation of individual tamarisk trees can lead to severe dieback the next season and death of the tree within several years. Tamarisk beetle defoliation over the course of at least one to several years can severely reduce the nonstructural carbohydrate reserves in the root crowns of tamarisk. Biological control of tamarisk by the larger tamarisk beetle will not eradicate tamarisk but it has the potential to suppress tamarisk populations by 75–85%, after which both larger tamarisk beetle and tamarisk populations should reach equilibrium at lower levels.
A primary objective of tamarisk biological control with the larger tamarisk beetle is to reduce competition by exotic tamarisk with a variety of native riparian flora, including trees (willows, cottonwoods, and honey mesquite), shrubs (wolfberry, saltbush, and baccharis), and grasses (alkali sacaton, saltgrass, and vinemesquite). Unlike expensive chemical and mechanical controls of tamarisk that often must be repeated, tamarisk biological control does not harm native flora and is self-sustaining in the environment. Recovery of native riparian grasses can be quite rapid under the once closed canopy of repeatedly defoliated tamarisk. However, tamarisk beetle defoliation can locally reduce nesting habitat for riparian woodland birds until native woodland flora are able to return. In some areas, tamarisk may be replaced by grasslands or shrublands, resulting in losses of riparian forest habitats for birds (Tracy and DeLoach 1999). Releases of tamarisk beetles in southern California, Arizona, and along the Rio Grande in western New Mexico, are currently delayed until concerns can be resolved regarding safety of tamarisk biological control to nesting habitats of the federally endangered southwestern willow flycatcher, Empidonax traillii Audubon subspecies extimus Phillips, which will nest in tamarisk.
External links
- Texas Agri-Life Extension Leaflet; Biological Control of Saltcedar (Uzbek source population, not mentioned, is D. carinata). PDF
- Texas Agri-Life Extension Newsletter; Beetle-Mania; Biological Control of Saltcedar in Texas, Volume 1, No. 2, Summer 2009 PDF
- Texas Agri-Life Research and Extension Program; Biological Control of Saltcedar: Using Natural Enemies to Combat an Invasive Weed Competing with Texas' Water Resources (Uzbek source population, not mentioned, is D. carinata). PDF
- USDA Agricultural Research Service and Texas Agri-Life Research and Extension Service Report of Information to the Public; Progress on Biological Control of Saltcedar in the Western U.S.: Emphasis -- Texas 2004-2009. PDF
- DeLoach, C. J.; Carruthers, R. I.; Lovich, J. E.; Dudley, T. L.; Smith, S. D. 2000: Ecological interactions in the biological control of saltcedar (Tamarix spp.) in the United States: toward a new understanding. In N. R. Spencer (ed.), Proceedings of the X International Symposium on Biological Control of Weeds, 4–14 July 1999, Montana State University. Bozeman, Montana, pp. 819–873. (PDF)