Thistle Tortoise Beetle
Encyclopedia
The thistle tortoise beetle, Cassida rubiginosa, is a tortoise beetle
, and as such belongs to the leaf beetle
s. It has a green carapace
(despite "Rubiginosus" being latin
for "rusty or rust-coloured"). bugguide.net
It is a species recorded in Britain and is native to Eurasia. It feeds on Canada thistle and was intentionally introduced to Virginia
to control thistles. It has spread to the northern United States
, following accidental introduction to Quebec in 1901. In Canada
it has also spread to New Brunswick
and Alberta
.
Cassida rubiginosa was brought to New Zealand
for use as a biological control agent against Canada thistle in 2006. In New Zealand this species is commonly referred to as the 'green thistle beetle' by landowners and biological control practitioners. Field releases of egg-laying adults were first carried out in Otago
and Southland
in spring 2007. Beetle populations at early release sites in Southland have become established and are already having a minor localized impact on the thistles. It is estimated that Canada thistle (known commonly in New Zealand as 'Californian thistle') costs landowners around $32 million per year in Otago and Southland alone.
Tortoise beetle
The tortoise beetles are an artificial grouping of tribes within the leaf beetle subfamily Hispinae. In past classifications, they have been variously placed as a family or a subfamily ; when it was recognized that this group was not monophyletic, it was split and the resulting tribes were...
, and as such belongs to the leaf beetle
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....
s. It has a green carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
(despite "Rubiginosus" being latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "rusty or rust-coloured"). bugguide.net
It is a species recorded in Britain and is native to Eurasia. It feeds on Canada thistle and was intentionally introduced to Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
to control thistles. It has spread to the northern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, following accidental introduction to Quebec in 1901. In Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
it has also spread to New Brunswick
New Brunswick
New Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...
and Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
.
Cassida rubiginosa was brought to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
for use as a biological control agent against Canada thistle in 2006. In New Zealand this species is commonly referred to as the 'green thistle beetle' by landowners and biological control practitioners. Field releases of egg-laying adults were first carried out in Otago
Otago
Otago is a region of New Zealand in the south of the South Island. The region covers an area of approximately making it the country's second largest region. The population of Otago is...
and Southland
Southland Region
Southland is New Zealand's southernmost region and is also a district within that region. It consists mainly of the southwestern portion of the South Island and Stewart Island / Rakiura...
in spring 2007. Beetle populations at early release sites in Southland have become established and are already having a minor localized impact on the thistles. It is estimated that Canada thistle (known commonly in New Zealand as 'Californian thistle') costs landowners around $32 million per year in Otago and Southland alone.