Amaranth is a plant extremely resistant to weather conditions: it is equally well tolerated by droughts and heavy rains, strong winds and even small frosts. This is a high-yielding crop that can bring a good income, especially in the production of high-quality food or feed for livestock. But, like all vegetable crops of this kind, amaranth amarant2 is subject to attacks from pests.
It should be noted that today there is no complete destruction of amaranth crops from pests anywhere: it shows good stability here as well. But the amount of harvest can be significantly reduced when growing both grain (or universal) and feed amaranth.
Insects are equally willing to absorb leaves and seeds. They are especially harmful during the growing season. For ripe amaranth, all the pests recorded in Europe are not so dangerous and can cause death, as a rule, to no more than 10% of the crop. At the same time, a large number of pests during the growth of amaranth can be fraught with a loss of up to 40% of crops.
Specific pests, peculiar only to amaranth, are not registered today. This facilitates opposition to them, since it does not require the development and search for special means that would preserve the crop. As a rule, for cleaning amaranth crops from insects, general precautions and countermeasures are sufficient. Moreover, in most cases, the treatment can be carried out before sowing and thus the crop is almost completely safe.
Among insects that can damage amaranth, in the territory of the CIS countries there are most often the following:
- common beet flea, southern beet flea, western beet flea and others;
- cruciferous flea (most often wavy and large Chaetocnema striped);
- beet aphid (leaf aphid, bean aphid);
- common beet weevil, gray beet weevil;
- meadow moth.
These pests are found mainly on chernozem soils, which, however, are most suitable for growing amaranth.
Beet flea belongs to the family of leaf beetles and, accordingly, harms the green part of amaranth. Beetles gnaw through the leaves. After a massive invasion of pests, up to 45% of the leaves turn into a “grid” of varying degrees of thinning. The beet flea’s stem does not touch, but its larvae eat roots. The larvae, however, unlike the adult flea, do not cause any special damage.
Beet flea has several varieties, each of which is characteristic of a particular area. Amaranth affects mainly three varieties of this pest – southern, western and common beet flea. The south is most commonly found in the Central Black Earth, Volga, North Caucasus, Ural and West Siberian regions. Western harms amaranth crops in the southern regions of Russia, in Ukraine and in the south of Belarus. Common distributed throughout the CIS countries.
Useful! Along with some other pests (for example, the flea-crucifer), beet flea is also called earth flea.
Beet flea have an oval convex body of black color with a metallic sheen. The length of the adult beetle is from 1.5 to 2.5 mm. Moves high jumps using the rear legs. Breed in the upper layers of the soil, mainly in plant residues. Females lay 5-12 eggs at a time, and for all their life in favorable conditions the female gives offspring in the amount of 200-230 individuals.
Beetroot flea prefers to lay eggs near plants suitable for food, including on amaranth fields. Eggs have a light yellow color, their size is up to 0.6 mm. The larvae and 1062_content_pagekukkolki too bright. The amaranth root system is strong enough to survive almost without loss of a small portion of the larvae. However, the plant weakens, which can make it less resistant to other types of pests and adverse conditions.
Beet fleas overwinter close to the surface among plant residues, often among weeds. An adult flea turns into good conditions for a month. Having developed, it comes to the surface, where it precipitates the green part of the plant under which it hatched. As a rule, this occurs in the spring, when the temperature reaches 7-9 degrees. The most significant crop losses occur during hot dry periods.
The damage threshold for amaranth is more than 25 beetles per 1 square meter, regardless of weather conditions, and 10–25 beetles per 1 square meter under the condition of a cool and dry spring. More precisely, the economic indicators of harmfulness are determined on the basis of the density of amaranth sowing.
The fight with beet flea on amaranth
The most effective and cost-effective are advanced methods of dealing with sugar beet flea. These include:
Careful weeding of weeds, as they most often cause the spread of earthen fleas. Weeds are more resistant to weather conditions and therefore are one of the favorite places for egg laying pests. Especially beet flea loves specimen weeds, therefore it is necessary first of all to pay attention to them. With a high resistance and rapid spreading of weeds, it makes sense to use herbicides, but they are considered an extreme measure when growing amaranth.
Providing amaranth with the necessary amount of fertilizers, as well as growing under optimal temperature conditions and other conditions that contribute to its strength and rapid growth. The more stable the plant and the earlier it began to develop in full force, the less damage will be from earthy flea of all kinds.
Caring for the soil, meeting the timing of harvesting and sowing (especially harvesting).
In case of significant damage to past harvested beetroot harvests, it is advisable to use mild chemical agents used to combat all types of earthy fleas on medicinal plants. The use of classical insecticides and pesticides on amaranth is unacceptable.
Cruciferous flea or flea-cruciferous flowers also belong to the leaf beetles and are widespread throughout the CIS, located up to 55 degrees north latitude. The farther south the region is and the faster the spring temperature rises to 10-15 degrees in spring, the higher the likelihood of damage to crops by this pest. Cruciferous flea due to jumping ability in a short time to occupy fairly large areas.
The damage caused by the flea-cruciferous amaranth is approximately comparable to the damage from the beet flea. In the same way, they gnaw through the leaves and are able to eat up to half of the green mass, and this depends little on sowing density: the beetles very quickly move to neighboring plants, regardless of distance. However, cruciferous flea is more thermophilic than beet. Because of this, in colder regions, it harms less, but in hot and drought-prone conditions it behaves much more actively.
Unlike black beet, cruciferous flea has a different color. On amaranth, wavy and large striped are most common. This flea justifies its name by the presence of contrasting bands on the back, easily recognizable. In addition to it, there can be found beetles of reddish-brown, dark blue or green color – these are also cruciferous fleas. In size, all types are comparable to beet flea – 1.5-2.5 mm in length. The body is also oval, convex, with a metallic sheen.
Flea-crucifer overwinters also in plant residues close to the soil surface. It comes to the surface when the temperature reaches 12-15 degrees. It does not like wet soils, almost always leaves them. But in the dry land during the warm season it breeds very quickly: as a rule, the cruciferous flea for 3 full development is enough for 3 weeks. The larvae also feed on the roots without causing significant harm.
Cruciferous flea flies primarily from cruciferous plants, for example, from cabbage. There is a high risk of its invasion if a shepherd’s purse, a colza, a Qatran Tatar (known as tumbleweed), wild radish, a field currant and other cruciferous plants grow nearby. In practice, this pest is unpretentious and can move from a variety of plants, including ornamental and wild, garden and field, and not necessarily cruciferous.
The threshold of damage depends on the amaranth variety. For low plants growing in warm terrain, it is 5-15 beetles per 1 square meter. For tall and cold-resistant plants, for example, for the varieties Voronezh, Fiery Giant, etc., from 15 individuals per square meter.
Cruciferous flea control methods
The extermination of weeds and the provision of the required level of soil moisture are two main conditions, under which the risk of cruciferous flea infestation is markedly reduced.
In view of the heat-loving nature of this pest, autumn weed control after the onset of cold weather almost completely deprives it of the possibility of wintering in the soil. The second autumn cultivation, necessary for the subsequent cultivation of amaranth, is also better carried out when cool weather has established and a sharp warming is no longer expected. Thus, the cruciferous flea, which settles under the upper soil layers, appears on the surface and dies quickly, not having time to lay eggs. If the clutch is already done, hatching the next generation of pests from it is also usually excluded.
The threshold of harmfulness depends on the stage of maturation of amaranth and starts from 2 beetles per 1 square meter. When the number of more than 10 beetles per 1 square meter of the plant is damaged by a quarter, yield losses up to 35%.
Fighting beet weevil
The main method of preventing beet weevil on amaranth crops is loosening and plowing the soil. Perepashka must be made during the laying of weevil eggs or after. As a rule, it is enough to wait for a steady temperature below +6 degrees: in such conditions, 4 1 dolgonosiki are no longer able to lay eggs. Deep plowing in front of severe cold throws the already laid eggs to the surface, where they do not survive the winter.
Weed control also reduces the risk of invasion of beet weevils. Pests leave the places where they can not get food, and food for them are, in particular, weeds and their remnants.
Also, beet weevils do not like wet soil, therefore, if possible, it is necessary to prevent its drying out.
If weevils have already spread on amaranth crops, only chemical control can help. Various organophosphorus compounds, neonicotinoids, pyrethroids and other insecticides show themselves well, but the admissibility of their use, as in the case of aphids, is in question. Organic insecticides can help with a small spread of pests (less than 5 beetles per 1 square meter).
The meadow moth belongs to the lepidoptera, the family of moths. It is a butterfly whose length is 1-1.5 cm, and its wingspan is 2-2.5 cm. The front wings are light brown with brown splashes and a yellow stripe; the rear have a yellowish tint, dark stripes and spots. The edges of the wings are fringed, which makes it possible to identify this pest. 5 Distributed in all regions of the northern hemisphere, located up to 60-65 degrees north latitude.
The meadow moth is the most cold-resistant species of the pest, fixed on amaranth. It winters close to the surface and is able to tolerate frosts down to –30 degrees. But it flies rather late, when the temperature is set at about +15 and higher.
The danger of a meadow moth lies, in particular, in its unpredictability. For many years he is able to show low activity, regardless of temperature conditions, and then suddenly intensify and cause significant damage. According to the observations, the moth becomes active every 5-6 years, but this is inaccurate information, which has a lot of factual refutations.
Caterpillars cause the greatest damage to amaranth. They gnaw leaves on all sides, leaving only the skeleton of the veins, and on some grain varieties they eat seeds. But the main crop losses are suffered by farmers breeding forage varieties: a meadow moth at its peak of activity can destroy up to 70% of the green mass of amaranth, which is in the middle phase of growth. Seed losses are less and are usually less than 35%.
The threshold of damage is 5-10 caterpillars per 1 square meter, depending on the size of amaranth and planting density.
Measures to combat the meadow moth
Meadow moths are not able to breed in hot and dry weather, so during droughts after a dry spring their invasions can be avoided. At the same time, if the drought was preceded by rain, there is a high probability that a meadow moth will appear in large numbers, since it needs plenty of water and it will start to look for it in the leaves of the plants. Therefore, monitoring is considered the first step to prevent the invasion of this pest. As soon as several butterflies or caterpillars are noticed on one site, measures should be taken to eliminate them.
Note! The meadow moth is more active at sunset and at night. During the day it can be practically invisible: it hides from the sun in wet and shady places.
On growing amaranth, biological methods are the most effective. Among the latter, the following means have shown themselves relatively well:
- bitoxibacillin in the amount of 2 kg / ha;
- Enterobacterin – 4 kg / ha;
- lepidocid – 2 kg / ha.
Liquid consumption when using these funds is 300-400 l / ha. Before use, you should consult with experts, since the effect of different means is slightly different for different varieties of amaranth and more significant – with a different number of pest.
Also, a trichogram is successfully used against the meadow moth on amaranth. It is released when hot and dry weather sets in, and monitoring has shown a high probability of the occurrence of a pest. A trichogram is a parasite that does not allow moth larvae to hatch from eggs. Effective two or three times with the interval of 4-5 days. Damage to amaranth trihogram does not cause.
Caterpillars are eaten by ground beetles and birds, but the latter can be fraught with the loss of part of the seeds, which is important when growing amaranth grain varieties.
The result can be summarized as follows. In order not to lose the harvest due to the invasion of pests on amaranth, it is best to apply early measures.
In the fall, it is plowing, loosening the soil, removing weeds, thoroughly cleaning the field of any plant residues – both amaranth or its preceding crops, and weeds. Cleaning the fields from plants is desirable to produce more than one time. The remains of green mass for the majority of non-cold-resistant pests are the best place for wintering, so even a small amount of it can provoke the reproduction of insects in the spring.
As for loosening and plowing, it is better to produce them when the weather is cool and no warming is expected. Some pests lay eggs rather late, so the later these activities are carried out, the greater the number of egg clutches, as a rule, can be destroyed. It is also important to go deeper into the ground: a number of pests, including the beet weevil, are buried in the soil by 0.3-0.5 m.
In the spring, it is necessary to thoroughly plow the land again and, after this, it is desirable to treat it with moderate chemical control means in order to remove those eggs or larvae that were able to survive the winter. It is also necessary to once again clean the soil from weeds. Use of herbicides is allowed. Farmers of the Voronezh region recommend spraying with roundap and similar products in the amount of 3 l / ha. Spraying is best done before sowing amaranth. Graminicides can be used to eliminate weeds and reproduce pests on them after sowing on young shoots.
If pests are found on amaranth at any growth phase, measures should be taken to control them as soon as possible. The most dangerous is aphid. The danger lies in its rapid reproduction and in that, large colonies are difficult to remove with soft chemical agents, and hard means are not suitable due to the intended use of amaranth. The second most dangerous is the beet weevil, which is capable of causing damage to the entire plant and is also susceptible to elimination using organic chemicals only at the very beginning of the filling of amaranth.
Under the condition of proper cultivation, as well as amaranth fertilizer with the substances necessary for its growth (exactly what you can read here), the appearance of an earthy flea — both beetroot and cruciferous — is unlikely. If it does appear, soft organic insecticides often cope with it quickly enough. Along with spraying the plants, it is necessary to find the source of the flea and eliminate it.
A meadow moth successfully counteracts almost all biological methods of pest control. Also, these methods are safe for amaranth.