Aphids - description, types, what they eat, life cycle, photo. Aphids on cereals Barley aphid
Now let's see what aphids look like. This is a small insect whose body length is several millimeters. Depending on the species, the body will be painted in a certain color. On personal plots, green, white, red and black aphids are most often found. An insect can be winged or wingless. Winged individuals quickly spread over the territory and contribute to the change of the host plant, wingless individuals mainly reproduce.
On a note! Based on what the aphid eats, it is easy to imagine what damage it can cause to agricultural land!
reproduction
Now it is worth considering how aphids reproduce. In autumn, females lay eggs on plants and they calmly survive the winter on them. In the spring, larvae appear from the eggs, which immediately begin to actively feed on the juices of their "master". After passing the molting stage, young individuals without fertilization give birth to wingless females.
On a note! As a result of parthenogenetic reproduction in just a month, only a female is able to become the ancestor of three generations, in which there will be several hundred thousand insects!
Closer to autumn, the production of winged males begins. They return to their "master", on which the females again lay their eggs.
Aphids belong to insects with incomplete transformation, that is, they do not have a pupal stage. Some species reproduce without laying eggs - live birth. Live larvae are formed parthenogenetically, and their embryonic period exceeds the life span of aphids, so the females are born already pregnant.
The most common types
As mentioned above, there are about 4 thousand species of aphids. It is not possible to consider all of them, so we will pay attention to those that are most common.
What is the danger?
The harm from aphids can be very large-scale, especially if you do not notice this pest in time and do not start fighting it.
And who eats aphids? The most notable natural enemies include:
- ladybug larvae;
- lacewing larvae;
- larvae;
- crickets;
- cicadas;
- ground beetles;
- earwigs;
- rider.
And so that these insects can help you in the fight against aphids, it is enough to attract them to your site by planting certain varieties of plants around its perimeter.
And finally, we suggest that you familiarize yourself with some interesting facts about aphids:
Schizaphis graminum Rond. -
systematic position.
Class Insecta, order Homoptera, suborder Aphidinea, superfamily Aphidoidea, family Aphididae, subfamily Aphidinae, tribe Aphidini, subtribe Rhopalosiphina, genus Schizaphis.
biological group.
Oligophages.
Morphology and biology.
The body of wingless virgins is 2.7-2.9 mm long, characterized by a light green color and a longitudinal middle stripe on the dorsal surface. Antennae reach half the length of the body. The tubules are long, cylindrical, unswollen, light, only brownish in front of the operculum, 1.7–2 times as long as the finger-like tail. The medial vein on the forewings branches once. Eggs are black, elongated oval in shape. The life cycle is monoecious. Winters in the egg stage on winter crops, as well as on carrion and wild cereals. In the life cycle, there is an alternation of sexual and asexual generations. In the zone of greatest damage, mass hatching of larvae of wingless parthenogenetic females from eggs is usually observed in late April - early May. The duration of the larval age is 8-15 days. A wingless parthenogenetic female lives up to 35 days and gives birth to up to 80 larvae. The pest feeds first on winter crops, and then on spring crops, in connection with which female settlers appear at the end of May. The winged parthenogenetic female lives 17-20 days and gives birth to up to 42 larvae. Insects live in large colonies on both the upper and lower sides of the leaves. By the time the grasses enter the tube, the density of aphids increases rapidly, so that huge colonies can completely cover the leaves. In September, when winter crops emerge, aphids fly to these fields from summer reservations. In late September-October, stripes appear, which give birth to males and females. Overwintering eggs are laid in October and continue until frost. The fecundity of females is 10-12 eggs, and life expectancy is 38-40 days. Eggs are laid in small groups of 2-4 per leaf sheath.
Spreading.
It lives in Southern Europe, Front, Central and Minor, Central Asia, North and South America, East and South Africa, Japan. On the territory b. In the USSR, the species is distributed north to 56°N. The greatest harmfulness is manifested in the steppe and forest-steppe zones: in the North Caucasus, in the Volga region, in the Central Chernozem zone, Crimea, and Ukraine.
Ecology.
The greatest number of aphids on grain crops is observed in late June - July. The most vulnerable phase of the plant during the colonization of aphids is the exit into the tube. During the period of maturation of spring crops, the number of aphids on them sharply decreases. For the development of wingless parthenogenetic females, the optimal conditions are the average daily temperature of 20-21°C at a relative humidity of 65-70%; winged - 25.8 ° C at a humidity of 70%. The appearance of the sexual generation is mainly influenced by the photoperiod and temperature. On the territory b. The USSR develops up to 15 generations per year. Mass reproduction is often preceded by years with cool and humid summers.
Economic value.
The greatest damage is caused to winter and spring wheat, winter and spring barley, rye, oats, corn, sorghum, millet and rice. From wild-growing cereal grasses, he prefers wild oat (Avena fatua L.), wheatgrass (Agropyrum repens P.B.), hedgehog (Dactylis glomerata L.), soft bonfire (Bromus mallis L.), red foxtail (Setaria glauca L.). Protective measures: destruction of wild-growing cereal grasses, application of insecticides in May-June. The most important entomophagous predators: Coccinella septempunctata L., C.
Cereal aphids
They belong to the group of non-migratory aphids, have similar biology; their development occurs on cereal plants. To preserve and continue the species, aphids have acquired amazing adaptations to environmental conditions.
In the annual cycle of development, the stages of eggs, larvae (four instars), nymphs pass and have four forms of an adult insect - wingless, winged parthenogenetic (viviparous without fertilization), sexual wingless females and winged females.
Common grass aphid: wingless viviparous female green, body oval-elongated, 2 mm long, sap tubes with dark ends, antennae longer than half of the body. The winged viviparous female is 1.6 mm long, has a green abdomen, the head and chest are brown, the antennae are longer than those of the wingless female.
Larvae in the first three instars do not have a tail, with the last molt a tail appears and the larva becomes an adult aphid.
The larva, intended for development into a winged female (nymph), differs in that in the second and third instars, the rudiments of wings are noticeable on its chest, after the fourth molt wings appear.
The oviparous female has no wings, differs from the wingless viviparous fusiform body shape, body length - 2.2 mm. The male is winged, with a thin, slightly curved abdomen and long antennae.
Aphids overwinter in the egg stage on the leaves of winter crops. The egg is oval, 0.6 mm long, 0.2 mm thick. A freshly laid egg is light green, with time it acquires a black shiny appearance. The fertility of autumn females is low.
In spring, with the onset of an average daily temperature of 8 - 10 degrees, larvae are reflected, which after 10 - 15 days turn into parthenogenetic female founders.
By the beginning of wax ripeness, the grains of the plant become unsuitable for nutrition. Aphids move and breed on wild cereals, carrion, sorghum crops, young plants of stubble crops.
With the advent of seedlings of winter aphids fly over to them and continue to multiply. In autumn, with a decrease in temperature, sexual individuals appear in the colonies - males and oviparous females.
Migrating grass aphids breed on grasses in summer, and in autumn they migrate to woody plants and overwinter in the egg phase.
HARMFUL
Cereal aphids, having piercing-sucking mouthparts, suck juices from plants, disrupt the formation of their vegetative and generative organs. The volume of juice absorbed per day is several times the weight of the feeding insect.
When populating an ear, aphids feed on juice from the stem, spike and flower scales. However, they cannot be completely pierced, so there are no characteristic damages on the grain. When ripe, a severely damaged plant forms a feeble and lightweight grain with sharp edges. The mass of grain in such plants is reduced by 5 - 10%. Its sowing qualities are also declining.
Aphids are carriers of pathogens of viral diseases from diseased plants to health. Honeydew secretions of aphids serve as a breeding ground for the development of pathogens of various diseases.
Pests belong to the order Homoptera, the Aphid family
culture.
Damage spring and winter wheat, rye, barley, oats.
Prevalence.
Distributed in the Central Black Earth, North Caucasian, Volga regions, in the south of Siberia and the Far East.
Description of the pest.
The body is up to 3 mm long, yellowish, light or grayish-green in color, rounded, soft. The legs and antennae are thin. The bluschko ends in an elongated outgrowth (tail) and bears a pair of thin tubular appendages (juice tubules). Adults are represented by wingless and winged forms.
Nature of damage.
Grass aphids initially concentrate on young upper leaves. As a result of sucking out the juice, discolored spots appear on the leaves, with severe damage, the leaves turn yellow and dry out. Damage to the barley aphid causes twisting of the upper leaf and non-earing of the shoot. Aphids reach the greatest mass in the period of heading - the milky ripeness of cereals. Aphids populate the ears and suck the juice from their various parts, which causes partial white spike and barrenness, and during the filling period - frailty, incompleteness of grains. Cereal aphids also carry viral diseases: barley yellow dwarf, wheat striped mosaic, maize crown and dwarf. When the ears ripen, the number of aphids sharply decreases.
pest biology.
Fertilized eggs overwinter on fodder plants. In the spring, larvae develop from them, turning into founding females. The latter, through parthenogenesis, accompanied by live birth, produce offspring - parthenogenetic females. In some generations, some of the individuals are winged female settlers. At the end of the annual cycle, striped females appear, giving birth to bisexual offspring. The last generation, after fertilization, lays overwintering eggs. Among cereal aphids there are monoecious (they feed only on cereals) and dioecious (there is a primary and secondary host plant) species. EPV - more than 5 ... 10 aphids per 1 stem (ear) and colonization of more than 50% of plants in the phases of tube entry - heading and more than 20 ... 30 aphids per 1 ear in the phase of grain filling.
Conditions affecting the development of the pest.
In the northern regions, hot dry weather in the spring-summer period contributes to aphid outbreaks, in the southern regions it is warm and moderately humid. At high humidity, aphids infect entomophoric fungi.
Fighting drugs.
Agrotechnical control measures.
Compliance with crop rotation, optimally early sowing of spring and late winter crops, post-harvest stubble stubble, destruction of cereal weeds, application of mineral fertilizers balanced in phosphorus and potassium, cultivation of early ripening varieties.
common grass aphid
Schizaphis graminum
common grass aphid- oligophage, pest of cereals. Prefers barley, oats, winter and spring wheat, millet, rice, sorghum. Successfully develops on Sudanese grass, corn, jugar, rye, bluegrass, couch grass, bonfire, fescue, tares and many other cereals. The view is monoecious. development is incomplete. Reproduction is bisexual and parthenogenetic. The egg hibernates. During the growing season develops up to 30 generations.
Morphology
Polymorphism
Winged virgin;
Wingless virgin;
Founder ,
All parthenogenetic generations of the common grass aphid, like all representatives of the true aphid superfamily, are viviparous.
Egg. Length 0.6 mm, thickness 0.2 mm. The shape is oval. A freshly laid egg is light green, becoming black and shiny as it develops.
Founder. Wingless viviparous female green. The body is oval-elongated. Length 2 mm. Juice tubules with dark ends. Antennae longer than half the body.
Larva in the first three instars it does not have a tail. The larva of the winged virgin is characterized by the appearance of rudiments of wings on the chest in the second and third instars. After the fourth molt, the wings appear completely.
Wingless virgin. Length 1.2-2 mm. The body is light green with a longitudinal green stripe on the dorsal side. No pollination, in short sparse needle-like hairs in one transverse row on segment. Tergum without sclerotization. Marginal tubercles papillary, small. Located on the prothorax, segments I and VII of the abdomen. Antennae without secondary rhinaria, reaching to the middle of the body. The tubules are long, cylindrical, light, not swollen, brownish in front of the operculum, 1.7-2 times longer than the finger-like tail.
winged virgin has secondary rhinaria on the third segment of the antennae. Length 1.6 mm, abdomen green, head and antennae brown. The antennae are longer than those of a wingless virgin.
Normal male (amphibian) winged. The abdomen is thin, slightly curved. Antennae are long.
Normal female (amphibious) wingless, fusiform body shape. Length 2.2 mm.
Development
Egg winters on the leaves of seedlings of winter cereal crops, wild cereals and on carrion.
Founder. In spring, with the onset of an average daily temperature of +8-10°C, larvae emerge from the eggs, which in 10-15 days grow into parthenogenetic founding females. Developing in 5-7 generations, each female produces 20-30 larvae.
winged virgin. This generation appears on fodder plants from the second generation. Pests fly to uninhabited plants, where they feed and reproduce by live birth. By the beginning of the wax ripeness of the grain, cultivated plants become unsuitable for nutrition. At this time, the pest migrates to wild cereals, sorghum crops, young plants of stubble crops. A little later, the winged virgins of the common cereal aphid prefer to colonize winter seedlings.
Normal females (amphibious), Normal males (amphibian) appear in the fall with a decrease in temperature.
mating period takes place on cereal plants in October-November. Fertility up to 12 eggs.
Eggs overwinter on the leaves of winter cereals.
Development features. The most favorable for the development of aphids is warm weather without heavy rains. Under such conditions, the pest reproduces in large numbers, especially in the southern regions of the range. The greatest damage is observed with a lack of moisture. During the growing season, the common grass aphid can produce up to 30 generations.
Maliciousness
common grass aphid- oligophage, harms grain cereals. Aphids form colonies and suck the juice from the above-ground organs of plants. They damage barley, oats, wheat, sorghum, millet, rice, rye, corn, jugar and many wild cereals. Lives on leaves, stems and leaf sheaths.
Severe infection of young plants during the period of emergence into the tube can cause serious harm and lead to the death of plants. Damaged plants degrade grain quality. Wheat shows stinginess, while oats and barley show huskiness. Due to the formation of empty spikelets, the yield decreases. Harm increases greatly with low humidity.
At the same time, the common grass aphid transmits viruses of barley yellow dwarfism and awnless brome mosaic.
Places of damage on the plant become discolored, sometimes redden.
Large grass aphid
Macrosiphum avenae
Large grass aphid- a pest of cereal plants. It affects oats, rye, barley, wheat, wild cereals. Sometimes found on plants of other families. Single view. development is incomplete. Reproduction is parthenogenetic and bisexual. The egg hibernates. During the growing season develops up to 30 generations.
Morphology
Polymorphism. The life cycle of a species consists of several morphologically distinct generations:
Winged virgin;
Wingless virgin;
Founder , emerges from the egg. Wingless.
Sexless virgin - several spring-summer generations of parthenogenetic females:
Stripes - appear in the colonies by autumn. Winged.
Normal females (amphigonal) - are hatched from streaks, lay eggs. Wingless.
Normal males (amphigones) are winged, they fertilize normal (amphigonal) females.
All parthenogenetic generations of the large cereal aphid, like all representatives of the true aphid superfamily, are viviparous.
Egg oval, freshly deposited greenish color. Becomes black and shiny after a few days.
Founder. The body is fusiform.
Wingless virgin. The tubules are 1.12-1.43 times as long as the tail. The cellular area occupies 0.2-0.3 lengths of the tube. Integument yellowish-green or dirty-red, to black, often shiny.
Body 2.5-4 mm, oval, fusiform. Antennae and juice tubes are black, eyes are red. The antennae extend past the middle of the body. The tail is light, lanceolate, 1.5 times shorter than the tubules.
winged virgin it is distinguished by a reddish-brown chest and a green or reddish abdomen. Length 3-4 mm.
Development
Egg winters on cultivated and wild cereals or winter crops. Egg development begins in April-May.
Founder. When temperatures rise to + 8-10 ° C, larvae appear. After 10-15 days, they turn into foundresses, which, in turn, produce up to 20-30 larvae.
winged virgin. Individuals migrate to uninhabited plants of the same species, where they continue to develop and reproduce parthenogenetically, by live birth.
Normal females (amphibious), Normal males (amphibian). The appearance of this generation of the pest is observed in the autumn period with a decrease in temperature.
mating period. By October-November, amphigones mate and lay eggs. The fertility of normal females is up to 12 eggs.
Development features. During the growing season develops up to 30 generations.
Maliciousness
Large grass aphid damages all spike crops and corn. Aphids form numerous colonies and suck juices from the ground organs of plants. Most harmful in dry years. Damaged plants reduce yield. The pest carries various viruses, including barley yellow dwarf.
