Beet borer
| Beet borer | ||||||||||||
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Beet borer ( Loxostege sticticalis ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Loxostegs sticticalis | ||||||||||||
| ( Linnaeus , 1761) |
The loxostege sticticalis ( Loxostege sticticalis ), also Wiesenzünsler called, is a butterfly from the family of Crambidae . When mass infested, its caterpillars are pests on clover , sugar beet and tobacco .
features
The beet borer moths show a slight sexual dimorphism with regard to the size or the span of the front wings. The males measure 18 to 20 mm, the females 20 to 26 mm. Other authors give a wingspan of 24 to 29 millimeters or up to 25 mm. In addition, the antennae of the males are toothed (serrat), those of the females are thread-shaped (filiform). The drawing and color of the wings vary greatly. The basic color ranges from a light brown to a darker brown to a reddish brown. The darker drawing is also very variable; it can have an indistinct inner transverse line, ring, kidney and cone blemishes as well as a mostly very clear, jagged outer transverse line, occasionally other spots also appear in the middle field. This drawing can also be almost completely missing in the other extreme area. The forewings can then be almost uniformly gray-brown, with occasionally still weakly indicated individual flaws. Gray fringes, a dark, narrow hemline towards the root followed by a narrow yellow to whitish cross band are typical. This is in the front half (towards the costal edge), but somewhat thickened near the middle. Often, in the contact area of the outer transverse line with the costal edge, another light spot has developed towards the edge area. Most of the specimens are also characterized by a rectangular, concave, light spot between the ring and kidney flaws, which is usually present even in specimens with few drawings; in the extreme case of specimens that are almost uniformly gray-brown in color, it can also be absent.
The upper sides of the hind wings are gray with a dark border line, which is in turn lined with a narrow light line towards the roots. Often a more or less complete, relatively wide, outer transverse line is also formed. The inner edge can be lightened. The undersides of the fore and hind wings are yellowish with a broad brown edge area and usually two further, broad, brown to dark brown cross bars.
The oval egg is orange-yellow shortly after being deposited and later turns gray.
The caterpillar is gray-green, later turns dark gray to black. The back line and the side line are dark. The adult caterpillar becomes up to 35 mm long. The head of the caterpillar is black with a light pattern.
The pupa is yellowish brown to dark brown; the cremaster has eight hook-shaped bristles.
Geographical distribution and habitat
The species is distributed in almost all of Europe, North Africa, North and Central Asia as far as North China and Japan, as well as introduced in North America. There the distribution area extends from southern Canada (Yukon to Nova Scotia) to the southern USA (Arizona to Massachusetts).
The beet borer can be found mainly on abandoned meadows, open landscapes and cultivated areas. In Russia and Siberia, it occurs mainly in the steppes, forest-steppe zones and in the southern taiga zone.
Way of life
The species forms one or two generations per year in the British Isles, with the second generation usually being incomplete. In southern Europe, up to four generations are formed each year. The situation is similar in Siberia, where only one generation is produced in the northern part of the range, but up to four generations in the south. In Central Europe, two generations are usually formed. The diurnal and nocturnal moths of the first generation can be found around May through August. They overlap with the second generation, which flies from around August. The moths are considered to be willing to migrate. In northern China it was observed that the spring generation in particular rose to great heights and could be transported far to the northeast. Before laying eggs, the females have to consume nectar. The females lay about 300 eggs (max. Up to 600 eggs) in small groups of three to eight eggs (max. Up to 20 eggs) on the food plants of the caterpillars, either on the sprouts or the leaves. The lifespan of the moths is around 4 to 20 days. The egg caterpillars hatch after 2 to 15 days. In the first generation, eggs are usually laid on wild herbs, while the eggs of the second generation are usually laid on cultivated plants. The caterpillars of the third larval stage often switch to cultivated plants when the wild herbs have been eaten or died. In total, more than 200 species of wild herbs are known that serve as a host plant. The main food plants of the caterpillars in Central Europe are clover ( Trifolium ), hemp ( cannabis ), tobacco ( Nicotiana ), Artemisia and sugar beet ( Beta vulgaris subsp. Vulgaris var. Altissima ) as well as snail clover ( Medicago ), cabbage ( Brassica ), Pisum ("peas" ) "), Carrots ( Daucus ), phaseolus , potatoes ( Solanum tuberosum ), spinach ( Spinacia ). The caterpillars spin individual leaves together and feed on the leaves. Initially, the leaves are skeletonized, later window, edge and pitting corrosion occurs. The caterpillars are found mainly in June and July (first generation) and from August until after wintering in April (second generation) of the following year. They feed on the underside of the leaf in a web. The caterpillars of the summer generation (s) develop quickly, they only need about 10 to 20 days to reach the fifth and final larval stage. Pupation takes place in a silk cocoon in the earth. The caterpillars also survive long periods of very low winter temperatures around -40 ° C. The puppet rest lasts 7 to 38 days.
Harmful effect
The beet borer is mentioned in most publications as a pest on clover, tobacco and sugar beet. In southern Europe, alfalfa in particular is said to be infested. In North America, where the species was introduced in the 19th century, the species is considered a pest on garden crops and crops. In Europe, however, there are hardly any indications of mass infestation and thus financially measurable harmful effects from this species. Control is therefore generally not necessary, in contrast to the closely related European corn borer ( Ostrinia nubilalis ), which can cause considerable damage in monocultures of corn . In northern China and eastern Russia, however, a mass increase is observed approximately every 10 to 12 years, which can result in considerable damage to crops, occasionally up to total failure. The limit of damage is reached at around 10 caterpillars per square meter. In Russia, the greatest damage occurs to sugar beets, beans, sunflowers, peas, hemp, corn, potatoes and vegetables. Grain is also often noticeably damaged, e.g. B. Barley, Wheat, and Sorghum .
Control measures can be carried out: deep plowing, loosening between the plants and piling up as well as harrowing to destroy the pupae. Other measures include: the application of insecticides during larval development and the release of parasites such as z. B. Trichogramma spp. ( Chalcidoidea ) and the spreading special Biologicals such Lepidocid and Bitoxibacillin.
Taxonomy and systematics
The taxon was scientifically described for the first time by Carl von Linné in 1761 as Phalaena Pyralis sticticalis in the work "Fauna Suecica". The holotype came from near Uppsala; it is now in the Linnean Collections of the Linnean Society of London, Burlington House, London. Later the species was also added to the genera Pyrausta cabinet , 1802, Parasitochroa Hannemann , 1964 (as a subgenus of Pyrausta ), Margaritia Stephens 1827 and Phlyctaenodes Guenée 1854. Today the position in the genus Loxostege Hübner , 1825, is recognized by almost all authors.
swell
Individual evidence
- ↑ a b c Slamka (1997: p. 22)
- ↑ a b c d e f g h i Interactive Agricultural Ecological Atlas of Russia and Neighboring Countries - Loxostege sticticalis by TL Kuznetsova and MA Chumakov
- ↑ Ian Kimber: Guide to the moths of Great Britain and Ireland (English)
- ↑ a b c d e f g Carter (1984: p. 209/10)
- ^ J. Donald Lafontaine and DM Wood: Butterflies and Moths (Lepidoptera) of the Yukon. In HV Danks and JA Downes (Eds.), Insects of the Yukon. P. 723–785, Biological Survey of Canada (Terrestrial Arthropods), Ottawa, 1997 Online (PDF; 454 kB)
- ↑ Feng, Hongqiang; Wu, Kongming; Cheng, Dengfa; Guo, Yuyuan: Spring Migration and Summer Dispersal of Loxostege sticticalis (Lepidoptera: Pyralidae) and Other Insects Observed with Radar in Northern China. Environmental Entomology, 33 (5): 1253-1265, 2004 doi : 10.1603 / 0046-225X-33.5.1253
- ↑ Hannemann (1964: p. 370) (as Pyrausta Parasitochroa sticticalis )
- ^ Carl von Linné: Fauna Svecica Sistens Animalia Svecicae Regni Mammalia, Aves, Amphibia, Pisces, Insecta, Vermes. Distributa Per Classes (et) Ordines, Genera (et) Species, Cum Differentiis Specierum, Synonymis Auctorum, Nominibus Incolarum, Locis Natalium, Descriptionibus Insectorum. 578 pp., Stockholm, Salvius, 1761 Online at Münchner SigitalisierungsZentrum Digitale Bibliothek (description p. 352)
- ↑ The Linnean Collections http://www.linnean-online.org/view/insects/phalaena_sticticalis.html ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Global Information System Common Moth
literature
- David J. Carter: Pest Lepidoptera of Europe with special references to the British Isles. 431 S., Dr. W. Junk Publishers, Dordrecht 1984 ISBN 90-6193-504-0 .
- Hans-Joachim Hannemann: Small butterflies or Microlepidoptera II. The moths (sl) (Cochylidae and Carposinidae) The moths (Pyraloidea). In: Friedrich Dahl: The animal world of Germany and the adjacent parts of the sea according to their characteristics and their way of life. Part 50, VEB Gustav Fischer Verlag Jena 1964
- František Slamka: The common moth (Pyraloidea) of Central Europe: determination - distribution - flight area - way of life of the caterpillars . 2nd partially revised edition, Bratislava 1997, ISBN 80-967540-2-5 .
