Earth fleas

from Wikipedia, the free encyclopedia
Earth fleas
Great rapeseed flea (Psylliodes chrysocephalus)

Great rapeseed flea ( Psylliodes chrysocephalus )

Systematics
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Family : Leaf beetles (Chrysomelidae)
Subfamily : Galerucinae
Tribe : Flea Beetle (Alticini)
Genre : Earth fleas
Scientific name
Psylliodes
Berthold , 1827

The earth fleas ( Psylliodes ) are a genus of flea beetles (Tribus Alticini) from the family of leaf beetles (Chrysomelidae).

features

They are relatively small leaf beetles with a sub-cylindrical outline when viewed from above, with body lengths between 2 and 4 millimeters. The elytra are either blue-metallic or reddish to yellowish in color and mostly not patterned or drawn, the head and pronotum can be of the same color or differently colored. The pronotum is convex with no furrows or indentations. The wing covers usually have clear stripes of dots. Among the related genera, the genus is well recognizable by the ten-membered antennae (the other genera usually have eleven members) and by the shape of the hind legs. The hind tarsi are not turned in at the tip of the rear rails, but a little in front of it (subapical) so that the rear rails continue behind the turn. The hind legs are, as is typical for the whole family, clearly thickened and give the animal jumping ability.

Biology and way of life

Beetles ( imagines ) and larvae are herbivorous (phytophag). They feed on a large number of species from over 30 families, especially the families Asteraceae , Chenopodiaceae , Solanaceae , Brassicaceae , Cannabaceae and Poaceae , the economically important agricultural pests mainly on hemp ( cannabis ), nightshade ( Solanum ) and cabbage ( Brassica ). Depending on the species, the larvae feed on the roots, mine in leaves or drill in stems, pupating always taking place in the ground. The imaginal beetles overwinter in the ground or in the litter. Depending on the species, one generation ( univoltin ) or several generations develop per year.

Damage

The signs of a flea infestation show on the leaves, which have small, one to two millimeters large, mostly round holes, in which the upper and lower leaf skin is preserved (so-called window corrosion ). Often only the leaf tissue is scraped off. When cold or drought slow down the growth of the young plants , the fleas often eat so much leaf area that the seeds die . The species that occur in cabbage plants overwinter as beetles in the mulch layer of hedges and in piles of stones or wood. During the first warm spring days, they emerge from their winter quarters and look for something to eat. They then attack the fresh cotyledons of the early-sown radishes, radishes or cabbage seedlings.

Prevention and control

The rapeseed flea , the most important agricultural pest of the genus in Germany, is controlled conventionally with insecticides . Since seed dressing with neonicotinoids is no longer allowed, active ingredients from the pyrethroids class have been used. However, the species evidently develops increasing resistance to it. Other species such as the hemp flea Psylliodes attenuatus are also fought with insecticides if they are more prevalent . As with all earth fleas, however, acceleration of youth growth is an important cultivation technique, as seedlings and young plants are particularly at risk. Other species such as the potato flea ( Psylliodes affinis ) are not considered worth fighting , at least in horticulture, because of minor damage. In the event of damage to cabbage plants, radishes and radishes by fleas in the home garden, we recommend keeping the soil moist and loosening the soil as a home remedy, in addition to rapid youth development. The use of crop protection nets (earth flea nets) with a mesh size of 0.8 mm is recommended in organic commercial vegetable growing. The manufacturers point out the careful side cover required here.

Systematics

The genus comprises about 200 species and is distributed worldwide, with the main distribution in the Palearctic , where 125 species occur. There are 9 species in Japan and 13 in North America, 6 of which, however, were introduced from Europe.

The genus Psylliodes is represented in the processing area of ​​the fauna Europaea with about 100 species and subspecies. Due to their political affiliations, they include, for example, endemic species from the Canary Islands and the Azores .

credentials

  1. ↑ a b c Haruo Takizawa (2005): A revision of the genus Psylliodes Latreille in Japan (Chrysomelidae: Alticinae). Insecta Matsumurana New Series 62: 175-185.
  2. ^ David G. Furth (1983): Alticinae of Israel. Israel Journal of Entomology 17: 37-58.
  3. ↑ Genus Psylliodes. at European Beetles. Determination tables, retrieved from Arved Lompe on October 24, 2015
  4. ↑ Udo Heimbach & Andreas Müller (2013): Incidence of pyrethroid-resistant oilseed rape pests in Germany. Pest Management Science 69: 209-216. doi: 10.1002 / ps.3351
  5. ↑ CT Zimmer, A. Müller, U. Heimbach, R. Nauen (2014): Target-site resistance to pyrethroid insecticides in German populations of the cabbage stem flea beetle, Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae). Pesticide Biochemistry and Physioly 108: 1-7. doi: 10.1016 / j.pestbp.2013.11.005
  6. ↑ Hop Flea Beetle at Interactive Agricultural Ecological Atlas of Russia and Neighboring Countries , accessed October 26, 2015.
  7. ↑ Fleas on potatoes. Plant protection information center in the garden of the Giessen Regional Council, accessed on October 26, 2015.
  8. ↑ Fleas on cabbage plants, radishes and radishes. online guide of the Rhineland-Palatinate Garden Academy, accessed on October 26, 2015.
  9. ^ Ross H. Arnett, JR, Michael C. Thomas, Paul E. Skelley, J. Howard Frank (editors): American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea. CRC Press, 2002. ISBN 978-1-4200-4123-1 , on page 666, limited preview on Google Books
  10. ↑ Psylliodes Berthold 1827. Fauna Europaea, Version 1.3, April 19, 2007, accessed on July 9, 2007 .

Web links

Commons : Earth Fleas ( Psylliodes )  - Collection of images, videos and audio files