Biological control - current trend in forest protection

• Published in: Forests in The Future Sustainable Use, Risks and Challenges pp. 105 - 117
• Main Authors: Tabaković-Tošić, M. (Institute of Forestry, Belgrade (Serbia)), Golubović-Ćurguz, V. (Faculty of Forestry, Belgrade (Serbia)), Radulović, Z. (Institute of Forestry, Belgrade (Serbia)), Georgiev, G. (Forest Research Institute of Bulgarian Academy of Sciences, Sofia (Bulgaria)), Mirchev, P. (Forest Research Institute of Bulgarian Academy of Sciences, Sofia (Bulgaria))
• Format: Conference Proceeding
• Language: English
• Published: Institute of Forestry, Belgrade (Serbia) 2012
• Subjects: biological control; forests pathogens and harmful insects; natural enemies

In the fight against plant diseases apply different methods of biological control that are based on various specific and nonspecific types of relationships between pathogens and microorganisms. Significant biological control, as defined above, most generally arises from manipulating mutualisms between microbes and their plant hosts or from manipulating antagonisms between microbes and pathogens. Direct antagonism results from physical contact and/or a highdegree of selectivity for the pathogen by the mechanism(s) expressed by the biological control agent. Hyperparasitism by obligate parasites of a plant pathogen would be considered the most direct type of antagonism because the activities of no other organism would be required to exert a suppressive effect. The utilization of hypovirulence as a biological control relies on the ability of the hypovirulent strains to disseminate and transmit their hypovirus to virulent strains. A classical example is the virus that infects Cryphonectria parasitica, a fungus causing chestnut blight. While various epiphytes and endophytes may contribute to biological control, the ubiquity of mycorrhizae deserves special consideration. Mycorrhizae are formed as the result of mutualist symbioses between fungi and plants and occur on most plant species. Because they are formed early in the development of the plants, they represent nearly ubiquitous root colonists that assist plants with the uptake of nutrients. Entomopathogenic organisms, various types of viruses, microsporidia, bacteria, protozoa, fungi, nematodes, which can under the favourable conditions cause the massive insect mortality and are of great breeding capacity, normally live in nature. Epizootics caused by naturally occurring viral and fungal pathogens are often responsible for spectacular crashes of insect pest populations. Although there are numerous entomopathogenic microorganisms, relatively small number of them has so far being practically used in the harmful insect control. Fungal entomopathogens have been used more frequently than other types of pathogens for classical biological control. The most comonly introduced species were Metarhizium anisopliae and Entomophaga maimaiga.