Lygus
Encyclopedia
The genus Lygus includes over 40 species of plant-feeding insects in the family Miridae
. At one time, nearly 200 species were classified as genus Lygus, but most of those have since been reclassified into new or existing genera. The term lygus bug is used for any member of genus Lygus. The more well-known lygus bugs are those that have agricultural
impacts. Some lygus bugs are very serious agricultural pests.
The insects appear as small oval creatures. Adult lygus are approximately 3 mm wide and 6 mm long, colored anything in a range from pale green to reddish brown or black. The bugs can be solid shaded or mottled, and have a distinctive triangle or V-shape on their backs. Adults are capable of flight
, and will often thus escape when approached. Nymph
s are wingless, and being light green in color, are often mistaken for aphid
s. However, lygus nymphs have harder shells, are typically more active, gain spots as they age, and lack aphid abdominal tubes.
Lygus bugs are known for their destructive feeding habits - they puncture plant tissues with their piercing mouthparts, and feed by sucking sap
. Both the physical injury and the plant's own reaction to the bugs' saliva cause damage to the plant. The females insert their eggs directly into the plant tissues using piercing ovipositor
s, and the newly emerged nymphs
are voracious consumers of plant tissue juices. Signs that a plant has been attacked by lygus bugs include discoloration, deformation of shoots and stems, curling of leaves, and lesions on the plant tissues.
Some methods of biological pest control
have proved useful against lygus bugs. For example, wasp
s of the genus Peristenus are parasitoids of lygus bugs; an adult wasp will inject an egg into a lygus nymph, and once the egg hatches the wasp's larva will consume the nymph from the inside out.
Miridae
The large and diverse insect family Miridae contains the plant bugs, leaf bugs, and grass bugs, and may also be known as capsid bugs. It is the largest family of true bugs belonging to the suborder Heteroptera, with over 10,000 known species and new ones constantly being described...
. At one time, nearly 200 species were classified as genus Lygus, but most of those have since been reclassified into new or existing genera. The term lygus bug is used for any member of genus Lygus. The more well-known lygus bugs are those that have agricultural
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
impacts. Some lygus bugs are very serious agricultural pests.
The insects appear as small oval creatures. Adult lygus are approximately 3 mm wide and 6 mm long, colored anything in a range from pale green to reddish brown or black. The bugs can be solid shaded or mottled, and have a distinctive triangle or V-shape on their backs. Adults are capable of flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
, and will often thus escape when approached. Nymph
Nymph
A nymph in Greek mythology is a female minor nature deity typically associated with a particular location or landform. Different from gods, nymphs are generally regarded as divine spirits who animate nature, and are usually depicted as beautiful, young nubile maidens who love to dance and sing;...
s are wingless, and being light green in color, are often mistaken for aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
s. However, lygus nymphs have harder shells, are typically more active, gain spots as they age, and lack aphid abdominal tubes.
Lygus bugs are known for their destructive feeding habits - they puncture plant tissues with their piercing mouthparts, and feed by sucking sap
Sap
Sap may refer to:* Plant sap, the fluid transported in xylem cells or phloem sieve tube elements of a plant* Sap , a village in the Dunajská Streda District of Slovakia...
. Both the physical injury and the plant's own reaction to the bugs' saliva cause damage to the plant. The females insert their eggs directly into the plant tissues using piercing ovipositor
Ovipositor
The ovipositor is an organ used by some animals for oviposition, i.e., the laying of eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly...
s, and the newly emerged nymphs
Nymph (biology)
In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult. In addition, while a nymph moults it never enters a...
are voracious consumers of plant tissue juices. Signs that a plant has been attacked by lygus bugs include discoloration, deformation of shoots and stems, curling of leaves, and lesions on the plant tissues.
- The tarnished plant bug (Lygus lineolaris) feeds on over half of all commercially-grown crop plants, but favors cotton, alfalfaAlfalfaAlfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
, beanBeanBean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....
s, stone fruitsPrunusPrunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, apricots and almonds. There are around 430 species spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament.-Botany:Members of the genus...
, and coniferPinophytaThe conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...
seedlings. This bug can be found across North AmericaNorth AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, from northern Canada to southern Mexico.
- The western tarnished plant bug (Lygus hesperusLygus hesperusThe Western tarnished plant bug is a serious pest of cotton, strawberries, and seed crops such as alfalfa. In the state of California alone the bug causes US$30 million in damage to cotton plants each year, and at least US$40 million in losses to the state's strawberry industry....
) is a very serious pest of cotton, strawberriesStrawberryFragaria is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. Although it is commonly thought that strawberries get their name from straw being used as a mulch in cultivating the plants, the etymology of the word is uncertain. There...
, and seed crops such as alfalfaAlfalfaAlfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
. In the state of CaliforniaCaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
alone the bug causes US$30 million in damage to cotton plants each year, and at least US$40 million in losses to the state's strawberry industry.
- The European tarnished plant bug (Lygus rugulipennis) is distributed throughout Europe, where it will feed on over 400 types of crop plant from peach treesPeachThe peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
to wheatWheatWheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
to lettuceLettuceLettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...
.
Some methods of 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...
have proved useful against lygus bugs. For example, wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...
s of the genus Peristenus are parasitoids of lygus bugs; an adult wasp will inject an egg into a lygus nymph, and once the egg hatches the wasp's larva will consume the nymph from the inside out.