Atheta coriaria

The predatory beetle Atheta coriaria (the synonym is Taxicera coriaria) belongs to the order beetles (Coleoptera), the family road beetles (Staphylinidae). This species occurs in the natural landscapes of Europe, North America, Australia, New Zealand, Chile and Canary Islands. The species has been introduced in many countries as an agent of biological control. The predator is widely used against cucumber midge (Bradysia brunnipes, Bradysia paupera), shore flies (Scatella stagnalis), and some stages (2nd age larvae) of western flower thrips (Frankliniella occidentalis). The predator can consume as alternative food various small insects living in substratum: moths, springtails, root mealy-bug larvae and others.

The beetle Atheta coriaria has coloration from light-brown to dark-brown. The adult individual is 3–4 mm in length. It has an oblong body and short wings. The body is covered with hairs. The insect is able to lift its abdomen upward and in case of danger it can run away or fly away. Each individual of the beetle consumes 10–20 preys per day. The larva is thin, pale-yellowish-white; in the process of development it becomes darker. The larva is enough mobile. The egg is not large, milk-white. The ontogenesis of the entomophage includes the following stages: an egg, a larva (3 ages), a pupa, and an imago. The time of ontogenesis cycle (egg-imago) lasts from 10 to 21 days dependently on the hydrothermal conditions of surrounding. The life span of the adult individual is about 20 days. Sex ratio is 1:1. The fertility of an entomophage female is 150–190 eggs. The level of population fluctuates dependently on season and the number of potential preys (food resource). In glass-covered ground the imago doesn't enter diapause. It is inherent cannibalism for the species in case of food deficiency.

Atheta coriaria Atheta coriaria Atheta coriaria

Application

The predatory beetle Atheta coriaria can be used widely in the protection system of vegetable and flower-ornamental crops, strawberry, and mushrooms. Taking into account its high motility it is not recommended to apply the entomophage in outdoor growing. The predator adapts well to various mediums (mineral cotton, coconut fiber) and thinwalled mats which are used for plant growing. Atheta coriaria has more durable life cycle and the development of its populations lasts longer than the development of Hypoaspis populations. Therefore it is recommended to use Atheta together with Hypoaspis for better effectiveness. The monitoring process of adult predators and larvae is not difficult. It is enough to disquiet the top layer (1–2 cm) of soil or plant substratum to find the movement of insects in it. The effectiveness of entomophage activity is checked by means of yellow sticky traps (rate of captured pests).

The biological agent is most effective when the density of pest population is low. In this case the rate of predator invasion is fulfilled in amounts of 1–5 adult individuals per 1 m2. If the release of the beetles is realized in the beginning of crop growth then it is enough 1 introduction of the predator. In the focuses of pest populations (especially for the representatives of the family Sciara) the release of the predator is fulfilled in amount of 10 individuals per 1 m2. The invasions of the entomophage are made systematically until the moment of numerosity stabilization. If necessary the releases are accomplished repeatedly.

The optimal hydrothermal conditions for the development and the reproduction of the predator are: a temperature of 25–28°C, a relative air humidity of 60–85%. The lowest thermal threshold for the development and the reproduction of the species is 12°C.

Do not apply this species for preventive invasions because under the high density of the predators and not sufficient food reserve the display of cannibalism is possible.

Advantages

  • the high motility of the species in the process of food search;
  • high feeding intensiveness;
  • introduction simplicity;
  • a wide range of activity;
  • the high speed of progeny reproduction (population growing);
  • the simplicity of the determination of entomophage level activity in the process of monitoring.

Storage and transportation

  • keep out of direct sunlight;
  • transport and store in dark place at a temperature of 10–15°C;
  • use within 1 week since the moment of reception.