Aphidoletes aphidimyza

Aphidoletes aphidimisa is a small insect of the family Cecidomyiidae (gull gnats), the order Diptera. It is wide spread in nature. The entomophage is one of the most important components of biological control for greenhouse crops in USA, Europe and Asia. In distinction from other species of the family, Aphidoletes doesn't injure plants by means of gull formation on leaves. It is an important biological agent for the effective control of different species of aphids (more than 60).

Aphidoletes aphidimyza Aphidoletes aphidimyza Aphidoletes aphidimyza

The adult individual is 2.5–3 mm in length, black. It has thin long legs and antennae. It feeds on the sweet excretions of aphids (the products of life activity). The egg is oval, light-orange. Its size is 0.1–0.3 mm. The female lays 100–250 eggs during its life cycle dependently on climatic conditions. It prefers to lay eggs in the colonies of the pest. The ontogeny phage of egg-larva takes about 9 days at a temperature of 15°C, 6 days at 23°C and 3 days at 27°C. There are three larva stages. The larva is 0.3–3 mm in length. It has a worm-shaped body with an underdeveloped motional apparatus. Initially it is transparent, orange. Later it is able to change a coloration into red, brown or grey dependently on the source of feeding. Aphidoletes consumes the larva stages of the pest previously killing them by way of toxin injection paralyzing the prey. The larva is able to kill from 3 to 50 individuals of aphids per day. In dense aphid colonies Aphidoletes kills much more preys than it is able to eat. The life span of these predators amounts to 4 weeks in their young stages and less than 2 weeks in an imago stage. After 7–14 days of life (at 21°C) in a larva stage it pupates in substratum (ground, gravel, organic remains). The cocoon is oval, brown, covered with sand grains, aphid skins and excrements. The adult emerges from the cocoon after 14 days. In nature the pupae enters diapause from the end of September till May in moderate regions. In greenhouses diapause is interrupted because of high temperatures.

Application

Aphidoletes aphidimisa is successfully applied for the biological control of aphids on cucumbers, tomatoes, chrysanthemums, roses and some other ornamental plants in greenhouses. The release of Aphidoletes is effective together with such predators as Aphidius colemani, Aphidius matricariae, Aphidius ervi or Aphelinus abdominalis.

The adult is active in the evening and at night. In daylight hours it hides in vegetative plant mass and shadow places. For the search of food source the imago is able to get over some distances.

Aphidoletes aphidimisa is usually applied in ground culture. This fact is explained by favourable conditions for pupation process (ground, gravel and etc.), which influences on the result of reproduction. In ground culture it may be enough effective 1 invasion of the predator taking into account subsequent reproduction. But as a rule 2–4 additional releases are made for the support of predator population. The rate of application is 3–5 individuals per 1 m2. The invasions of the predator are realized near the colonies of the pests.

Under substratum culture (mineral-wadded substratum, coconut fiber) the reproduction of predator population is considerably limited because required conditions for pupation are absent. Aphidoletes should be considered in this situation as a temporary method for the control of developing aphid colonies. The invasion of the predator is made in accounts of 5–10 individuals per 1 m2 herewith the interval between the releases should be 1–2 weeks (in dependence on the density of pest population). The increase of the rate of predator application promotes the more effective (quick) control of the pest organism..

The optimal hydrothermal conditions for the development of Aphidoletes are a temperature of about 25°C, and a relative air humidity of 70–90%. Humidity is important for the successful emergence of adult individuals from the cocoons. Therefore under the invasion of the predator it is necessary to support the substratum (vermiculite, peat, sand) containing the predator cocoons in humid state.

Some pesticides exert negative influence to Aphidoletes aphidimisa. The most sensitive to the application of chemicals are the adults.

Advantages

  • application for the most of vegetable and ornamental crops in glass-covered ground;
  • the control of about 60 aphid species;
  • considerable search abilities;
  • the high intensiveness of feeding.

Transportation and storage

  • transport and to store at 6–8°C;
  • don't expose to influence of direct sunlight;
  • apply within 18 hours since the moment of reception.