Farklı Organik Asitlerin, Bal Arılarındaki (Apıs Mellıfera L.) Amerikan Yavru Çürüklüğü Hastalığı Etkeni Paenıbacıllus Larvae Üzerine Antimikrobiyal Etkisi

Abstract

The causative agent of American Foulbrood is a spore-forming Gram (+) streptobacilli bacterium called Paenibacillus larvae. When honey bee (Apis mellifera L.) larvae are infected with P. larvae, death is inevitable. Although the control methods applied in most of the studies achieve success against the vegetative form, these methods are ineffective against the spore form. In addition, the control methods used should not cause toxic effects on bees, cause residues in bee products, and should be applicable and accessible in the beekeeping. For this reason, a method that is effective on the spore form of P. larvae does not leave residues in bee products, and applicable or accessible in the beekeeping industry has not yet been discovered. ii The aim of this thesis study is to determine the effects of organic acids (oxalic acid, formic acid, lactic acid, acetic acid) which are currently used in the control methods against Varroa destructor that is another bee pest that causes large colony losses, on vegetative, sporo-vegetative and spore forms of P. larvae. Organic acids have not been tested on P. larvae before, and this study has been carried out to close the gap that has been detected in the literature. Within the scope of the thesis, a method for obtaining all forms of P. larvae was developed, but the experiments were rearranged with vegetative and spore forms because the sporo-vegetative form could not maintain its stability. Organic acids were prepared by the concentrations used in the control V. destructor in beekeeping (oxalic acid 3.5%, formic acid 60%, acetic acid 50%, lactic acid 15%). Organic acids have been tested on P. larvae with different doses (5 mL, 2.5 mL, and 1.25 mL), different treatment times (1 day, 3 days, 7 days), and different bacterial densities (1x104 CFU, 1x103 CFU, and 1x102 CFU). To test the effectiveness of organic acids in the experimental groups, viable cell counting was performed using the pour plate method. Washing processes were carried out before the organic acids were applied to the spore form of P. larvae. Then, when no results could be obtained with the pour plate method, the experiments were carried out again in a liquid medium to support the germinating of P. larvae spores. As a result, it has been observed that organic acids have a bactericidal effect on the vegetative form of P. larvae and are ineffective against the spore form. It is thought that the use of organic acids in the field in beekeeping for the control of V. destructor, provides the transformation of P. larvae spores present in the hive into vegetative form in early spring, and the disinfection of the vegetative forms that are likely to be present in the environment during the first instar larvae of the brood. Although the use of organic acid does not have a preventive effect on P. larvae infection, it has been proven that it has an effect on reducing the infection rate and reducing the transmission rate, as it destroys the vegetative forms in the environment.