DIURAPHIS NOXIA PDF
Although D. noxia feeds on leaves and flowers/seedheads of grasses, it appears to inject a polypeptide toxin that affects the entire plant (Hewitt et al., ). The Russian wheat aphid, Diuraphis noxia Kurdjumov, is one of the most important pests of small grains throughout the temperate regions of. The genome of Diuraphis noxia, a global aphid pest of small grains. Nicholson SJ(1)(2), Nickerson ML(3), Dean M(4), Song Y(5), Hoyt PR(6).
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The Russian wheat aphid, Diuraphis Noxiais one of the most invasive agricultural pests found across the globe. As a result, these aphids are now found on every continent except Australia and Antarctica. Most recently, the Russian wheat aphid has invaded Canada and the United States. P and Sloderbeck, ; Zhang, et al. Russian wheat aphids are able to survive in a variety of habitats as a result of their ability to withstand a wide range of temperatures. Unlike other aphids which move to woody areas throughout the course of the year, the Russian wheat aphids live inside the rolled leaves of cereal crops and grasses year round.
Of these cereal crops, wheat and barley are the plants most commonly infested by Diuraphis noxia. Other cool season grasses such as crested wheat grasses, intermediate wheat grasses, and wild ryes serve as host plants when the preferred cereal crops are not available. These cool season grasses are essential for the survival of the Russian wheat aphid during the warm seasons between wheat harvest and wheat emergence.
P and Sloderbeck, Russian wheat aphids are green and relatively small, ranging from 1. The body of the aphids is spindle-shaped, appearing wider in the middle and tapering on each end. Russian wheat aphids have short antennae and a piercing-sucking stylet on their head. When the aphid is observed from the posterior end, the sides create what looks like a double tail.
Russian wheat aphids have reduced cone-shaped cornicles with their wings which appear like shoulder pads. Hodgson and Karren, ; Michaud J. P and Sloderbeck, ; Hein, et al. The Russian wheat aphid life cycle begins inside a parthenogenetic female, where development takes place without fertilization.
These females give birth to live, genetically identical daughters. Young nymphs appear similar to the adult aphid but covered with a white waxy filament. The maturation of Diuraphis noxia depends on the temperature of their environment. If the temperature in their environment is below 25 degree Celsius, they mature at a slow rate. Whereas an aphid living in an environment with a temperature at or above 25 degrees Celsius will grow at a much faster rate. On average, Russian wheat aphids take nine to 55 days to become a mature adult aphid.
In some populations, sexual reproduction takes place between males and females just before winter. The female lays eggs that overwinter, and emerge again in the spring. Merchant, ; Michaud J. P and Sloderbeck, ; Sutherland, The Russian wheat aphid can reproduce both sexually and asexually. North American populations consist solely of females, so they do not mate at any point in their lives.
Other non-North American populations mate in the fall, though there is little additional information available. Hodgson and Karren, ; Merchant, The Russian wheat aphid can reproduce sexually and asexually. During asexual reproduction, female aphids do not lay eggs, and instead give birth to live genetically identical daughters over the course of 60 to 80 days.
Asexual reproduction causes massive growth within the population. In North American populations, there have been no traces of male aphids.
As a result, the female aphids are unable to reproduce sexually and rely solely on asexual reproduction to produce their offspring. Diuraphis noxia reproduces in high numbers forming colonies that benefits its survival. On average, Russian wheat aphids take 9 to 55 days to reach maturity and start reproducing.
Temperature that best suits the reproduction cycle of the aphids ranges from 15 to 21 degrees Celsius. Although Russian wheat aphids can survive in a variety of temperatures, a temperature below 4 degrees Diurraphis will stop aphid reproduction. On average during temperatures between 15 and 21 degrees Celsius, a mature Russian wheat aphid can produce up to 1.
In some cases, females can reproduce up to four nymphs in a single day.
In non-North American populations, sexual reproduction may occur in the noxai, where females mate and then lay eggs that overwinter.
Most Diuraphis noxia females give birth to live young, which is likely a significant energy investment on their part. In some populations, eggs are produced by sexual reproduction, and these eggs contain provisioning provided by the female parent, allowing for the eggs to survive through winter. After birth or after the eggs are laid, no further parental interaction or care is given. Diugaphis lifespan of D. Environmental temperature has a great effect on their lifespan.
Merrill and Holtzer, ; Merrill, et al. Diuraphis noxialike most aphids, lives in large colonies. There are several generations of winged aphids produced each year. Aphids in general are poor fliers and strongly rely on wind to move them from area to area as they search for new host plants.
The rest of the aphids are wingless. The every day behavior of Russian wheat aphids can be sorted into phases, based on their feeding activity.
During the first phase, the aphids find a potential plant to feed on. This is a random process that is referred as the pre-alighting behavior. During the second phase, the aphids will begin to examine and explore the plant’s leaves searching for a spot to feed upon. This phase is known as the exploration of the plant surface and the immediate subepidermal tissues.
The third and fourth phase are joined phases. In these phases the aphids look for the parts of the plant that are nutritional diutaphis and begin eating. The aphids feed from the phloem in the leaves.
When an aphid is onxia taking the nutrients it needs, it moves on to a new potential plant. Alate Russian wheat aphids fly to plants in new areas to establish new colonies. Since aphids are poor fliers, it is unlikely that they travel long distances unless on a particularly strong wind current. Wingless aphids and nymphs are sedentary and remain in the same general area. Russian wheat aphids communicate with each other by producing an alarm pheromone.
The alarm pheromone is secreted by the cornicles located at the end of the abdomen. The alarm pheromone helps detect another aphid or a predator near them. If a predator is near they respond by dropping off the host plant. Russian wheat aphids feed on phloem from plants, using their stylet mouth parts to pierce the plant material.
They tend to be found noia small diyraphis fields noxiia grasses year round. They favor mostly wheat and barley and in cold seasons they switch their diet to wheatgrass, intermediate wheatgrass, and Canada wild rye.
They start feeding on the top or edge of the plant depleting the plants nutrients. Once the plant loses its nutrients and a colony noxa large numbers begins to form, the leaf begins to rapidly roll inward, protecting the aphids from dangers including natural enemies and insecticidal sprays.
During the Russian wheat aphid feeding process they release toxins that cause discoloration on the plants they feed on.
The toxin released inside the plants causes the plants to become discolored and can appear white, purple, and yellow to the naked eye. Dijraphis feeding on developing plants they can prevent the head of the plant to open up stunting the plants development. In some cases, the Russian wheat aphid causes the edges of wheat grains to become bleached, halting the grains development. The food habits of Diuraphis noxia are greatly influenced by seasonal changes.
Diuraphis noxia (Russian wheat aphid)
During the fall season, they move from plant leaves to the inside of curled leaves to be protected from cold temperatures.
In warmer seasons, Russian wheat aphids appear on the edges of leaves where they feed. Natural predators of the Russian wheat aphids include the convergent lady beetle Hippodamia convergensthe seven-spotted lady beetle Coccinella sepempuncatathe lady beetle Hippodamia variegataAphidiid wasps Aphidiidaehover flies Diptera: SyrphidaeScymnus beetles, lacewings Chrysopidaerove beetles Staphylinidaeand spiders Araneae.
The Russian wheat aphid hides in the curled leaves of a wheat plant, making it hard for larger predators to reach them. Convergent lady beetles, seven-spotted lady beetles and Scymnus beetles are small enough to crawl duuraphis the curled part diurapnis the leaves and feed on the aphids.
They also drop off their host plants when a predator is near, and alert the colony of a predators’ presence with an alarm pheromone. As one of the most invasive agricultural species in the world, Russian wheat aphids have an extensive impact on the ecosystems they invade.
Russian wheat aphid
As their habitat range continues to expand into new regions, Russian wheat aphids are continually destroying the plants they feed on, which include a variety of cereal grains, such as wheat and barley.
While feeding, the Russian wheat aphid transfers a toxin that causes extreme discoloration. Plants that become heavily infested with the toxin have leaves with identifiable purple, white, or yellow streaks.
Heavy feedings from Diuraphis noxia can also prevent normal formation and distortion of grain heads and leaves. In some cases their feeding averts the proper unrolling of leaves and causes the formation of bleached heads diuraphjs poorly shaped grains.
As a result, grain production and quality is drastically reduced. Like all aphid diurapnis, Diuraphis noxia has an endosymbiotic bacterium, Buchnera spp. This is an obligate relationship for both organisms, as Buchnera can survive outside of bodies noxiq aphids. In return, Buchnera produces essential amino acids that Russian wheat aphids need to survive and do not get from their plant phloem diet.
Russian wheat aphids are also parasitized by many parasitoid wasp species. The wasps lay an egg inside of the aphid’s body, which cause the noxiq mummification and death of the aphid.