Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescoping generations—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs.
Hemiptera is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of piercing-sucking mouthparts. The name "true bugs" is often limited to the suborder Heteroptera.
Closteroviridae is a family of viruses. Plants serve as natural hosts. There are four genera and 59 species in this family, seven of which are unassigned to a genus. Diseases associated with this family include: yellowing and necrosis, particularly affecting the phloem.
Barley yellow dwarf (BYD) is a plant disease caused by the barley yellow dwarf virus (BYDV), and is the most widely distributed viral disease of cereals. It affects the economically important crop species barley, oats, wheat, maize, triticale and rice.
Potato leafroll virus (PLRV) is a member of the genus Polerovirus and family Solemoviridae. The phloem limited positive sense RNA virus infects potatoes and other members of the family Solanaceae. PLRV was first described by Quanjer et al. in 1916. PLRV is transmitted by aphids, primarily the green peach aphid, Myzus persicae. PLRV is one of the most important potato viruses worldwide but particularly devastating in countries with limited resources and management. It can be responsible for individual plant yield losses of over 50%. One estimate suggests that PLRV is responsible for an annual global yield loss of 20 million tons. Symptoms include chlorosis, necrosis and leaf curling.
Herbivores are dependent on plants for food, and have coevolved mechanisms to obtain this food despite the evolution of a diverse arsenal of plant defenses against herbivory. Herbivore adaptations to plant defense have been likened to "offensive traits" and consist of those traits that allow for increased feeding and use of a host. Plants, on the other hand, protect their resources for use in growth and reproduction, by limiting the ability of herbivores to eat them. Relationships between herbivores and their host plants often results in reciprocal evolutionary change. When a herbivore eats a plant it selects for plants that can mount a defensive response, whether the response is incorporated biochemically or physically, or induced as a counterattack. In cases where this relationship demonstrates "specificity", and "reciprocity", the species are thought to have coevolved. The escape and radiation mechanisms for coevolution, presents the idea that adaptations in herbivores and their host plants, has been the driving force behind speciation. The coevolution that occurs between plants and herbivores that ultimately results in the speciation of both can be further explained by the Red Queen hypothesis. This hypothesis states that competitive success and failure evolve back and forth through organizational learning. The act of an organism facing competition with another organism ultimately leads to an increase in the organism's performance due to selection. This increase in competitive success then forces the competing organism to increase its performance through selection as well, thus creating an "arms race" between the two species. Herbivores evolve due to plant defenses because plants must increase their competitive performance first due to herbivore competitive success.
Citrus tristeza virus (CTV) is a viral species of the genus Closterovirus that causes the most economically damaging disease to its namesake plant genus, Citrus. The disease has led to the death of millions of Citrus trees all over the world and has rendered millions of others useless for production. Farmers in Brazil and other South American countries gave it the name "tristeza", meaning sadness in Portuguese and Spanish, referring to the devastation produced by the disease in the 1930s. The virus is transmitted most efficiently by the brown citrus aphid.
The beet leafhopper, also sometimes known as Neoaliturus tenellus, is a species of leafhopper which belongs to the family Cicadellidae in the order Hemiptera.
Banana bunchy top virus (BBTV) is a plant pathogenic virus of the family Nanoviridae known for infecting banana plants and other crops. It is aphid transmitted.
Strawberry vein banding virus (SVBV) is a plant pathogenic virus and a member of the family Caulimoviridae.
The soybean aphid is an insect pest of soybean that is exotic to North America. The soybean aphid is native to Asia. It has been described as a common pest of soybeans in China and as an occasional pest of soybeans in Indonesia, Japan, Korea, Malaysia, the Philippines, and Thailand. The soybean aphid was first documented in North America in Wisconsin in July 2000. Ragsdale et al. (2004) noted that the soybean aphid probably arrived in North America earlier than 2000, but remained undetected for a period of time. Venette and Ragsdale (2004) suggested that Japan probably served as the point of origin for the soybean aphid's North American invasion. By 2003, the soybean aphid had been documented in Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Dakota, Virginia, West Virginia, and Wisconsin. Together, these states accounted for 89% of the 63,600,000 acres (257,000 km2) of soybean planted in the United States in 2007.
Myzus persicae, known as the green peach aphid, greenfly, or the peach-potato aphid, is a small green aphid belonging to the order Hemiptera. It is the most significant aphid pest of peach trees, causing decreased growth, shrivelling of the leaves and the death of various tissues. It also acts as a vector for the transport of plant viruses such as cucumber mosaic virus (CMV), potato virus Y (PVY) and tobacco etch virus (TEV). Potato virus Y and potato leafroll virus can be passed to members of the nightshade/potato family (Solanaceae), and various mosaic viruses to many other food crops.
Acyrthosiphon pisum, commonly known as the pea aphid, is a sap-sucking insect in the family Aphididae. It feeds on several species of legumes worldwide, including forage crops, such as pea, clover, alfalfa, and broad bean, and ranks among the aphid species of major agronomical importance. The pea aphid is a model organism for biological study whose genome has been sequenced and annotated.
Jacobiasca formosana, the tea jassid, is an insect species belonging to the subfamily Typhlocybinae of the family Cicadellidae. Plant hosts include Gossypium (cotton) species and, notably, Camellia sinensis. The species is distributed throughout East, Southeast, and South Asia.
Blueberry shoestring virus (BBSSV) is a disease-causing virus that is commonly transmitted by the aphid vector, Illinoia pepperi. The blueberry shoestring virus disease is very prominent in highbush and lowbush blueberry plants in the northeastern and upper Midwest of the United States. Symptoms can vary significantly depending on the environment, but the most common disease symptoms are reddish streaking on young stems, reduced vigor and strap-shaped leaves. The blueberry shoestring virus disease can be managed by eliminating the aphid vector through the use of biological, chemical or cultural controls. In severe cases, the disease leads to an extensive loss of yield and marketable fruit.
Tritrophic interactions in plant defense against herbivory describe the ecological impacts of three trophic levels on each other: the plant, the herbivore, and its natural enemies. They may also be called multitrophic interactions when further trophic levels, such as soil microbes, endophytes, or hyperparasitoids are considered. Tritrophic interactions join pollination and seed dispersal as vital biological functions which plants perform via cooperation with animals.
Rhopalosiphum rufiabdominale, the rice root aphid or red rice root aphid, is a sap-sucking insect pest with a wide host range and a global distribution. As a member of the superfamily Aphidoidea, it is one of 16 species of the genus Rhopalosiphum. Adults and nymphs are soft-bodied and usually dark green with brown, red, or yellow tones. Like all aphids, reproduction is sexual and asexual, depending on the environmental conditions and host plant. Rice root aphids cause injury to external plant parts, namely the roots or stem, by feeding on plant sap and vector several important plant viruses. The hosts of this pest extend across multiple plant families with most belonging to Rosaceae, Poaceae, and Solanaceae. R. rufiabdominale is universally associated with Prunus species but also infests various field crops, greenhouse vegetables, cannabis, and other ornamental plants. While this aphid originates from east Asia, it spans nearly every continent. Dispersal is particularly widespread across the United States, India, and Australia, with crop damage documented in multiple instances, although economic losses are primarily associated with Japanese rice crops. Nonetheless, it remains a pest of serious concern due to its high mobility, discrete habitat, and adaptive plasticity, giving it the rightful reputation as a successful invader.
Carrot virus Y (CarVY) is a (+)ss-RNA virus that affects crops of the carrot family (Apiaceae), such as carrots, anise, chervil, coriander, cumin, dill and parsnip. Carrots are the only known crop to be infected in the field. Infection by the virus leads to deformed roots and discolored or mottled leaves. The virus is spread through insect vectors, and is currently only found in Australia.
Saskia A. Hogenhout, is a Dutch professor of entomology and ecology specialising in molecular plant, microbe and insect interactions.
