Bactra venosana
Encyclopedia
The Nutgrass Borer or Nutsedge Borer (Bactra venosana) is a moth
of the Tortricidae
family. It has a wide distribution, from southern Europe
, North Africa
and Asia Minor
to India
, Sri Lanka
, southern China
, Malaya
, Australia
and into the Pacific where it is found on Java
, Borneo
, the Philippines
, Taiwan
, Timor
, the Solomons, the Carolines and Fiji
. It was introduced to Hawaii
in 1925 to control nutsedge. It is now found on Kauai
, Oahu
, Molokai
, Maui
, Lanai
and Hawaii
.
The larvae feed on Cyperus rotundas and Kyllingia species, including Kyllingia brevifolia and Kyllingia monocephala. They bore the stem of their host plant.
Affected plants first show a withering of the inner leaves, which become yellow and finally die. Young larvae are pale, glassy yellowish, with a shining black head. Full-grown larvae are green or pale yellowish. They spin a tube of silk in the stem and in this cocoon sheds its skin to turn into a pupa of about 5-7 mm long.
Moth
A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...
of the Tortricidae
Tortricidae
Tortricidae is a family of moths, commonly known as tortrix moths, in the order Lepidoptera. Tortricidae is a large family with over 9,400 species described, and is the sole member of the superfamily Tortricoidea. Many of these are economically important pests. Olethreutidae is a junior synonym...
family. It has a wide distribution, from southern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
and Asia Minor
Asia Minor
Asia Minor is a geographical location at the westernmost protrusion of Asia, also called Anatolia, and corresponds to the western two thirds of the Asian part of Turkey...
to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
, southern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Malaya
Malay Peninsula
The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and into the Pacific where it is found on Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
, Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
, Timor
Timor
Timor is an island at the southern end of Maritime Southeast Asia, north of the Timor Sea. It is divided between the independent state of East Timor, and West Timor, belonging to the Indonesian province of East Nusa Tenggara. The island's surface is 30,777 square kilometres...
, the Solomons, the Carolines and Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
. It was introduced to Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
in 1925 to control nutsedge. It is now found on Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
, Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
, Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
, Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
, Lanai
Lanai
Lānai or Lanai is the sixth-largest of the Hawaiian Islands. It is also known as the Pineapple Island because of its past as an island-wide pineapple plantation. The only town is Lānai City, a small settlement....
and Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
.
The larvae feed on Cyperus rotundas and Kyllingia species, including Kyllingia brevifolia and Kyllingia monocephala. They bore the stem of their host plant.
Affected plants first show a withering of the inner leaves, which become yellow and finally die. Young larvae are pale, glassy yellowish, with a shining black head. Full-grown larvae are green or pale yellowish. They spin a tube of silk in the stem and in this cocoon sheds its skin to turn into a pupa of about 5-7 mm long.