Dacnusa sibirica

The parasitic wasp Dacnusa sibirica belongs to the family Braconidae, the order Hymenoptera. It is an aboriginal species for the most of European and North American countries. This wasp is a widely spread inner parasite of miner flies. Usually in IPM (integrated pest management) programs it is applied together with Diglyphus isaea. In nature it affects representatives of the species Phytomyza asteris and Phytomyza syngenesiae. In the condition of glass-covered ground the wasp is applied against local and introduced miner flies (Liriomiza trifolii, Liriomiza bryoniae and Liriomiza huidobrensis).

The adult individual is dark-brown or black, 2–3 mm in length. The distinctive feature of Dacnusa sibirica from Diglyphus isaea under visual definition is long antennae.

Dacnusa sibirica Dacnusa sibirica Dacnusa sibirica

The female by means of olfaction (smell) finds a host-insect and pierce it with an ovipositor laying eggs inside the body of a prey larva. It prefers larvae of the 1st and the 2nd ages. The larva of the miner fly continues its usual normal development. Having completed feeding it pupates. But inside its puparium the larva of the parasite begins to develop. It pupates in the same place (endoparasitism). The period of pre-imago development under the optimal temperature (at 22°C) lasts 16 days. The life span of adults amounts to 7 days. Sex ratio is 1:1. The female of Dacnusa sibirica is able to lay about 12 eggs per day. The fertility of the female for her whole life span is about 100 eggs. The pupa of the parasite at a temperature of 5°C is able to preserve its viability about 6 months. The adult parasite is light-demanding.

Application

Dacnusa sibirica is applied against miner flies for the defense of vegetable crops (the tomato, the sweet pepper, the lettuce) and ornamental plants (the rose, the gerbera, the chrysanthemum).

The rate of parasite application depends on the colonization of leaves by larvae of miners. The miner larva population is denser the effectiveness of the parasite is higher. Under releases of 10–20 thousands of parasites per 1 ha effectiveness amounts to 61–71%. If the density of miner larva population is low it is necessary to increase ratio to 1:1 or 1:3. It is relevant to apply the entomophage for the control of miners in winter, spring and autumn because the arrival of high temperature (summer period) reduces considerably the vitality of the parasite. For prophylaxis the invasions of Dacnusa sibirica are realized in a rate of 0.1–0.2 individual per 1 m2.

Advantages

  • application for the defense of many crops;
  • the affection of the most injurious species of miner flies;
  • activeness under relatively low temperature;
  • excellent search ability under the low density of pest population;
  • the duration of parasite life cycle is a little faster than the duration of pest life cycle.

Transportation and storage

  • keep out of direct sunlight;
  • transport and store in dark conditions at a temperature of 10–15°C;
  • apply within 18 hours since the moment of reception.