''Adelphocoris lineolatus'', is commonly known as the Lucerne bug or the alfalfa plant bug, and belongs to the family

Miridae The Miridae are a large and diverse insect family at one time known by the Synonym (taxonomy), taxonomic synonym Capsidae. Species in the family may be referred to as capsid bugs or "mirid bugs". Common names include plant bugs, leaf bugs, and g ...

. It is an

agricultural pest A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment fo ...

causing vast amounts of damage to numerous crops, but primarily to alfalfa crops around the globe.

Synonyms

* ''Adelphocoris binotata'' Goeze * ''Adelphocoris chenopodii'' Fallen, 1807 * ''Adelphocoris italica'' Tamanini, 1961 * ''Adelphocoris lineolatus baltrumensis'' Schumacher, 1911 * ''Adelphocoris lineolatus binotatus'' Wagner, 1960 * ''Adelphocoris lineolatus bisbipunctata'' Tamanini, 1982 * ''Calocoris chenopodii'' * ''Calocoris chenopodii implagiata'' * ''Calocoris chenopodii lineolatus'' * ''Calocoris lineolatus bisbipunctatus'' Reuter, 1891

Geographical distribution

Adelphocoris ''Adelphocoris'' is a genus of capsid bugs in the tribe Mirini. It is part of a genus group that now includes '' Creontiades, Megacoelum'' and '' Pseudomegacoelum''.Chérot F, Malipatil MB ( 2016) A review of ''Adelphocoris – Creontiades – ...

lineolatus'' are an Old World Species native to

Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

Northern Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

, and the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

. In 1917, this species had been introduced into

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. In the

Nearctic realm The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

, these insects range from Southern

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

and Northeastern

, to the south of

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

, and west of

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

Habitat

Alfalfa plant bugs require a certain set of optimal conditions in order to thrive and become a pest in any country. ''A. lineolatus'' are primarily located in humid environments with cold temperatures. Commonly one can find these plant bugs in either fields or grasslands, in both dry and damp areas.British Bugs
/ref> However, alfalfa plant bugs are not successful in salty lakes, deserts, sand dunes, windy weather, or very warm climates. ''Adelphocoris lineolatus'' will easily adapt to cooler environmental conditions, which has allowed them to invade a large amount of territory in

External anatomy and physical characteristics

''Adelphocoris lineolatus'' have an elongated body shape and are large in body size. Alfalfa plant bug males body size ranges from, 8.3-9.5 millimetres. Whereas, the females are a little bit smaller than the males having a body size between, 7.6 and 8.3 millimetres. Their antennae are usually the same length as their body size, sometimes a bit shorter. A longitudinal brown triangle is located on the middle of their corium. The scutellum of ''A. lineolatus'' have two longitudinal brown lines on the surface. The pronotum of the alfalfa plant bug will have two black spots on it. It commonly observed that their

femora The femur (; : femurs or femora ), or thigh bone is the only bone in the thigh — the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg. The top of the femur fits in ...

are spotted with brown specks. Also, the ocular index between male and female ''Adelphocoris lineolatus'' differs. Males have an ocular index of 0.83 millimetres. Whereas, females have an ocular index of 1.5 millimetres. Certain regions of their bodies are covered with black hairs, and others with pale coloured hairs. The body colour can range from a light green to a pale brown. Nymphs are green and have red eyes. In ''A. lineolatus'' nymphs there is an absence of wings, but in adult species wings are seen.

Reproduction

Alfalfa plant bugs exhibit migratory behaviour, which allows ''Adelphocoris lineolatus'' to rapidly increase their population sizes. Adult females can lay 80 to 300 eggs, into branches and young stems of host plants, females will begin to lay eggs in the end of July. The eggs will develop in 8–12 days, but some of the eggs will overwinter. Eggs that have overwintered in stems, hatch in late May or early June. Less than five percent of alfalfa plant bug eggs will hatch in the same year they are laid. A majority of the eggs will enter a period of

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

. This causes a decline in the reproductive activity of second-generation adults. The developmental process of ''A. lineolatus'' involves five nymphal

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

s, and between late June and October adults are seen.

Ecological and economical damage

''Adelphocoris lineolatus'' nymphs and adults are generalists feeding on a variety of crops including alfalfa, bean, cotton, peach, and strawberry crops. Adults and nymphs will consume the reproductive and vegetative organs of their host plants, which are primarily

alfalfa Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial plant, perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, ...

and

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

crops. By feeding on the reproductive and vegetative organs of their host plants, they cause stunted growth and deformation of flowers, fruits, and leaves. The eggs that have overwintered will hatch in spring and the ''A. lineolatus'' nymphs will begin to feed on various crops. Lucerne bugs will migrate onto summer host plants, such as, alfalfa and cotton because they will allow the successful colonization of ''A. lineolatus.'' Alfalfa and cotton crops can be either, flowering or non-flowering. ''Adelphocoris lineolatus'' have a stronger preference towards flowering crops, in comparison to non-flowering crops. Flowering alfalfa and cotton crops promote higher survival rates and nymphal development amongst this particular species. Non-flowering crops increase adult mortality rates and decrease fecundity in ''Adelphocoris lineolatus''. On flowering alfalfa plants survival rates were five times higher than on non-flowering alfalfa crops for ''A. lineolatus'' adults. Flowering cotton crops had survival rates that were almost four times greater than that on the non-flowering cotton crops. Taking a closer look at ''Adelphocoris lineolatus'' nymphs, it was noted that nymphs took a greater amount of time to develop on non-flowering plants, which directly impacted the degree of damage they could cause to their host plants. A substantial degree of damage is done to flowering and non-flowering crops because ''Adelphocoris lineolatus'' nymphs and adults have similar feeding habits, allowing them to inhabit one particular plant for their whole life cycle. Nymphs and adults belonging to ''Adelphocoris lineolatus'' are capable of reducing crop yields by 50% within two years of their infestation on crops. The livelihood of many individuals within developing countries has been negatively affected due to the rapid spread of alfalfa plant bugs, due to their migratory behaviour. They have destroyed numerous alfalfa crops around the globe. In Canada alone they have caused a deficit of $50 million to the alfalfa plant industry.

Semiochemicals

Alfalfa plant bugs have a greater degree of attraction towards flowering plants in comparison to non-flowering plants. The three main crops that ''Adelphocoris lineolatus'' show the most attraction for are flowering alfalfa, cotton, and mung bean crops. Biologists have observed a relationship between three chemosensory proteins found in the antennae of ''A. lineolatus'' and the

semiochemical A semiochemical, from the Greek wiktionary:σημεῖον, σημεῖον (''semeion''), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication c ...

s released by flowering alfalfa, cotton, and mung bean crops resulting in a greater attraction towards these crops. ''AlinCSP1, AlinCSP2,'' and ''AlinCSP-3'' are the three chemosensory proteins found in the antennae of ''Adelphocoris lineolatus.'' Insects are heavily dependent upon their olfactory sensilla in order to detect chemical stimuli from the environment they are found in. Within the ''Adelphocoris lineolatus'' species, it has been found that they detect the semiochemicals released by their host plants in order to invade them. The chemosensory proteins, ''AlinCSP1, AlinCSP2,'' and ''AlinCSP-3'' contain a high binding affinity to the semiochemicals released by flowering alfalfa, cotton, and mung bean plants. The greatest amount of ecological and economical damage is experienced by these flowering plants because of the semiochemicals they release into the environment, attracting ''Adelphocoris lineolatus''.

Control techniques

''Adelphocoris lineolatus'' are commonly known as the alfalfa plant bug, due to the excessive amount of damage they cause to alfalfa crops around the world. In order to decrease and prevent the rapid dispersal of ''A. lineolatus'' certain control methods need to be implemented, to decrease the amount of ecological and economic damage these pests cause.

Insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s are not commonly used to decrease or stop ''Adelphocoris lineolatus'' from infesting crops because these insects have become resistant to certain chemicals present in insecticides. ''A. lineolatus'' nymphs have become resistant to the following chemical ingredients commonly used in insecticides, mono-methanimidamide, fufenozide, buprofezin, azad irachtin, and triazophos. An alternative from these chemicals would be to use insecticides made of

pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and ''Chrysanthemum coccineum, C. coccineum''). Pyrethroids are used as commercial and hou ...

neonicotinoid Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active insecticides chemically similar to nicotine, developed by scientists at Royal Dutch Shell, Shell and Bayer in the 1980s. Neonicotinoids are among the widest-used insecti ...

carbamate In organic chemistry, a carbamate is a category of organic compounds with the general Chemical formula, formula and Chemical structure, structure , which are formally Derivative (chemistry), derived from carbamic acid (). The term includes orga ...

avermectin The avermectins are a group of 16-membered Macrolide, macrocyclic lactone derivatives with potent anthelmintic and Insecticide, insecticidal properties. These naturally occurring compounds are generated as fermentation products by ''Streptomyces a ...

, or

organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered ...

since alfalfa plant bugs are not resistant to these chemicals. Insecticides can be an effective and efficient method of controlling pests, but they do cause a great deal of damage to our environment and we should refrain from using them if possible.

Insect pheromones Insect pheromones are neurotransmitters that serve the chemical communication between individuals of an insect species. They thus differ from kairomones, in other words, neurotransmitters that transmit information to non-species organisms. Insect ...

have successfully been implemented to reduce the amount of damage ''Adelphocoris lineolatus'' cause to numerous agricultural crops. Sexually mature ''A. lineolatus'' produce a mixture of two pheromones known as, (E)-2-hexenyl butyrate (E2HB) and (E)-4-oxo-2-hexenal (4-OHE). These pheromones are responsible for high reproductive rates amongst the alfalfa plant bug. To reduce reproductivity between female and male ''Adelphocoris lineolatus'', an excessive amount of hexyl butyrate (HB) needs to be added to the mixture of E2HB and 4-OHE. The addition of HB reduces the attraction between female and male ''A. lineolatus''. Hexyl butyrate is responsible for stopping the release of sex pheromones from female alfalfa plant bugs, which disrupts communication between the two sexes, and reduces reproductive success in this particular species.

References

External links

''Adelphocoris lineolatus'' pest

Bug Guide

Management Techniques
{{Taxonbar, from=Q2824296 Hemiptera of North America Insects described in 1778 Mirini