Feltiella acarisuga

Feltiella acarisuga (the synonym is Therodiplosis persicae) is a predatory midge of the family Cecidomyidae. It is widely spread in nature on the territory of Europe and Asia. The midge is one of the most effective and widely spread natural enemies of spider mites of the species Tetranychus urticae and Tetranychus cinabarius.

The body of an adult individual is small, fragile, pink-brown with little twisted antennae and long legs, 1–2 mm in length. Sex ratio in population is approximately 1:1. The adult feeds mainly on the sugary excretions of pests. The female lays eggs in the colonies of spider mites on the underside of a leaf. The life span of the adult predators is 4–5 days. The eggs are nitidous, semitransparent, oblong, 0.1×0.25 mm in size. The female lays on an average 30 eggs. The larva emerges from the egg in 2 days. There are 4 larva stages in the process of acariphage ontogenesis. The larva is orange-brown. During growth its length changes from 0.2 to 2 mm and its diameter does from 0.2 to 0.4 mm. The duration of larvae stage is 5–10 days dependently on hydrothermal conditions and food availability. Immediately after hatching the larva begins to search the source of food. Having found food source it pierce the body of a prey by means of mandibulae (jaws) after that it eats away the contents of a mite. In the feeding process of the acariphage its larva is able to kill 15 adult individuals, 30 larvae of different stages and 80 eggs of the pest per day. The larva of the predator pupates along the veins of leaf undersides. The pupa is white, 1–1.5 mm in length. The duration of pupa stage is 4–6 days.

Feltiella acarisuga Feltiella acarisuga Feltiella acarisuga

Application

Feltiella acarisuga is applied in the complex defense programs of crops in glass-covered ground against different biotypes of spider mites. The best results of predator application are achieved on the cucumber, the tomato, the eggplant, and also on the rose and the gerbera. Feltiella is a very important component for the defense system of tomatoes because the application of Phytoseiulus persismilis as the general acariphage in many cases doesn't ensure the proper control of pest population. The application of this predator together with Phytoseiulus persimilis and Ambliseius californicus is effective for the most of crops in glass-covered ground. But it is not recommended the application of the predator under the high density of Macrolophus caliginosus population. This organism is polyphage therefore predatory process against Feltiella acarisuga is possible. Feltiella acarisuga is not able to control the mites of species Tarsonemidae and Eriophyidae.

The critical conditions for egg and larva stages are a temperature higher than 30°C, and a relative air humidity lower than 30%. The optimum hydrothermal conditions are a temperature of about 20°C and a relative humidity of 70–80%.

The adult individuals have excellent abilities for the search of food source.

It is not recommended to use Feltiella acarisuga for prophylactic because the deficit of food may cause the death of the predator. In the conditions of short daylight period the predator is not very effective because it may enter diapause.

Invasions are realized by means of inundation releasing every week 250–500 individuals of acariphage per ha during 4–6 weeks (in dependence on pest number) for the stabilization of Feltiella acarisuga population. If necessary the rate of invasion is increased. It is recommended to make invasions directly near the focuses of pest populations.

Advantages

  • application on many of crops including tomatoes;
  • excellent search abilities;
  • the elimination of all the stages of the pest;
  • the easy discovering of larvae under monitoring.

Storage and transportation

  • don't expose to direct sunlight;
  • transport and store at 10–15°C;
  • apply immediately or within 18 hours since the moment of reception.