Beneficial species for pest control in growing of vegetable crops

Biological production of vegetables is a modern system for providing of health and qualitative food. Protection and use of the beneficial species in the vegetable agrocenoses are an element of the biological systems for growing. The biocenoses are complex communities including plant species, animal organisms and microorganisms. Relationships between them are complex and they have been formed in the process of their ontogenetic and phylogenetic development. A part of these relationships, mainly the antagonistic ones are the basis of the biological control which is intentionally developed antagonistic and competitive relationships between the pest on one hand and their enemies (parasites, predators and pathogens) on the other hand. This method for pest control is becoming more widely used in vegetable growing as an alternative of the chemical method. Biological control includes the application of micro- and macro-bioagents. Micro-bioagents (viruses, bacteria and fungi) are the agent of diseases for the pests. They are the basis of the microbiological method for control. Microorganisms and products of their life cycle are used for pests control in this method. In our country a technology for production of mamestrin – product from nuclear polyhedrosis virus is developed for control of cabbage moth. There are also known granulosis on cabbage white butterflies – Baculovirus brassicae Pillot. The product Dipel 2Х is on the basis of the bacterium Bacillus thuringiensis var. kurstaki and it is applied in the practice for control of cabbage moth. The fungi Verticillium lecanii Zimm., Aschersoniа aleyrodis Webb and Paecilomyces fumoso-roseus Was. are effective against the greenhouse whitefly. The strains of V. lecanii could control the number of the thrips and aphids. The including of the microbial plant protection products such as Preferal WG (on the basis of P. fumoso-roseus Apopka 7), in the integrated and biological plant protection systems is an alternative for decrease of greenhouse whitefly density. The rhizobacteria, obligate parasitic bacteria, symbionts of entomopathogenic nematodes, fungi, parasites on the eggs and female and endophytic fungi are the most suitable for control on the population of the root-knot nematodes. Egg-pathogenic fungus Paecilomyces lilacinus (Thom) Samson is one of the most widely tested agents for biocontrol against plant parasitic nematodes. P. lilacinus is a soil-inhabiting fungus which colonizes the plant roots and it is a pathogen for root-knot nematodes. The product BioAct WG is developed from the spores of P. lilacinus strain 251 and it is offered on the trade network. The bioproducts based on the strains Trichoderma spp., Fusarium spp. and Pythium oligandrum are the most widespread and the most active ones for control on the diseases in cultivated plants. The fungus Trichoderma is among the most frequently occurred saprophytic fungi. Many of its isolates are with antagonistic action and some of them could stimulate the growth of the cultivated plants. It colonizes the soil around the plant roots and protects them from the pathogenic fungi by competition for space and nutrients; through release of biologically active substances; mycoparasitism and stimulation of the plants. The species of genus Trichoderma grows quickly, forms conidia in abundance and they have a great spectrum of enzymes including cellulose disintegrating. There are plant protection products, registered in the world, based on the strains from this fungus and these are the following products: Trichodermin NG, Trichodex, Promot WP, Ecosom, Supresivit, Remedier WP, Virisan, Tusal, Rootshield WP etc. The marco-bioagents are natural enemies of the pest – parasites and predators. The entomophages and acarophages are of great importance for the biological regulation of the harmful insects and mites in the agrocenosis. The parasite Encarsia formosa Gah. (Hymenoptera:Aphelinidae) is known in the practice and gives good results against greenhouse whitefly. To control this pest by the method of introduction it could also be used the parasites Eretmocerus eremicus (Rose and Zolnerowitch) and Eretmocerus mundus (Mercet). Species from Aphidiidae family parasitize the leaf aphids. The species Aphidius colemani Viereck and Aphidius matricariae Holiday, are main parasites against the cotton leaf aphids (Aphis gossypii Glover) and green peach aphid (Myzus persicae Sulzer). The endoparasite Dacnusa sibirica Telenga parasitize the leaf miners. The parasites Opius pallipes Wesm. and Diglyphus isaea Walker are established in these pests. The most widely application among the bioagents against the cutworms have the egg parasite Trichogramma evanescens Westw. Some predatory bugs from genus Orius regulate the number of the thrips. The predatory mites from genus Amblyseius are used successfully against them. The populations of these pests could be also controlled by the soil-dwelling predatory mites Hypoaspis miles and H. аculeifer. Frequently occurred predators in leaf aphids are the species from family Coccinellidae (Coccinella septempunctata L., Adalia bipunctata L., Adonia variegata Goeze etc.) and from family Chrysopidae (Chrysopa carnea Steph., Chrysopa septempunctata Wesm., Chrysopa formosa Br., Chrysopa prasina Burm.). The flies from family Syrphidae (Syrphus balteatus Deg., Syrphus corollaе F., Syrphus ribesii L.) participate also actively in regulation of the leaf aphid number. The aphid predatory midge Aphidoletes aphidimyza Rondam is occurred in the colonies of different leaf aphids on the vegetable crops. The most efficient predators against spider mites are Phytoseiulus persimilis A. H. The use of beneficial species for control on the pests in the agrocenosis is with a number of advantages compared to the chemical method. It is in total correspondence with the natural mechanisms for maintenance of the biological balance; resistant forms of pest to it may not occur, because their mutability is accompanied by an adequate variability in their antagonists and parasites; it is harmless for the environment and human health. Disadvantages of this method for control are the slower effect and the necessity of creation of appropriate conditions for development and preservation of beneficial species.BG; bg; EFSAfocalpoint@mzh.government.b