Marija Milutinović

Persistence and Efficacy of Three Diatomaceous Earth Formulations Against Sitophilus oryzae (Coleoptera: Curculionidae) on Wheat and Barley

Abstract The insecticidal and residual efficacy of three diatomaceous earth (DE) formulations, Insecto, PyriSec, and SilicoSec, against Sitophilus oryzae (L.) on barley and wheat was assessed. For this purpose, 4-kg lots of barley and wheat were treated with the above-mentioned DE formulations, in three dose rates (0.75, 1, and 1.5 g/kg grain) and stored at 26°C. Samples of these lots were taken at the day of storage, and every 45 d, until the completion of a 450-d period of storage. Bioassays were conducted by exposing S. oryzae adults to these samples, at 26°C and 57% RH. In these bioassays, the DE efficacy was evaluated by recording adult mortality after 24 h, 48 h, 7 d, and 14 d of exposure on the treated grains. After the 14-d count, all adults were removed, and the samples were left at the same conditions for an additional 45 d, to evaluate the capacity for progeny production in the treated grains. Adult mortality after 14 d of exposure was exponentially decreased with time. During the first 270 d of storage, mortality was >90%, and progeny production was <1 adult per sample, whereas after 270 d a gradual decrease in adult mortality occurred, with a resulting increase in progeny production. Generally, the three DE formulations tested were equally effective against S. oryzae adults. During the first 270 d of storage, the DE formulations were equally effective on both grains tested, but from 315 d of storage and on, S. oryzae mortality was higher on barley than on wheat. At this interval, progeny production was gradually increased, especially on grains treated with the lowest DE dose rate. However, even this rate caused a satisfactory level of mortality (>90% after 14 d of exposure) during the first 270 d of storage.

Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Francisella tularensis and their co-infections in host-seeking Ixodes ricinus ticks collected in Serbia

To evaluate the prevalence rate of tick-borne bacterial pathogens, unfed adult Ixodes ricinus ticks were collected from vegetation in 2001, 2003, and 2004 at 18 localities throughout Serbia. A total of 287 ticks were examined by PCR technique for the presence of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Francisellatularensis. The highest prevalence rate was that for B. burgdorferi sensu lato (42.5%), followed by A. phagocytophilum (13.9%) and F. tularensis (3.8%). The presence of five B. burgdorferi sensu lato genospecies, namely, B. burgdorferi sensu stricto, B. afzelii, B. garinii, B. lusitaniae, and B. valaisiana was identified by restriction fragment length polymorphism (RFLP) analysis. The most frequent B. burgdorferi sensu lato genospecies was B. lusitaniae, followed by B. burgdorferi sensu stricto. Co-infection by B. burgdorferi sensu stricto and B. lusitaniae was frequently observed. Co-infection by B. burgdorferi sensu lato and A. phagocytophilum and co-infection by B. burgdorferi sensu lato and F. tularensis appeared in 24 ticks. Sequencing of p44/msp2 paralogs of Serbian A. phagocytophilum showed that they were unique and distinct from those of A. phagocytophilum in US and UK. This is the first report of B. garinii, B. lusitaniae, B. valaisiana, as well as A. phagocytophilum and F. tularensis infected ticks in Serbia. These findings indicate a public health threat in Serbia of tick-borne diseases caused by B. burgdorferi sensu lato, A. phagocytophilum and F. tularensis.

Analysis of pathogen co-occurrence in host-seeking adult hard ticks from Serbia

Past studies in Serbia have reported concurrent infections of Ixodes ricinus ticks with Borrelia burgdorferi sensu lato genospecies, Anaplasma phagocytophilum and Francisella tularensis. As a step forward, this investigation included a broader range of microorganisms and five most common and abundant tick species in Serbia. Five tick species were identified (Dermacentor marginatus, D. reticulatus, Haemaphysalis punctata, H. concinna and I. ricinus) and analyzed for the presence of seven pathogens. Anaplasma ovis, A. phagocytophilum, Babesia canis, B. burgdorferi s.l., Coxiella burnetii, Rickettsia helvetica and R. monacensis were detected. Sequencing of samples positive for F. tularensis revealed the presence of Francisella-like endosymbionts. No Bartonella spp. DNA was amplified. Concurrent infections were present in three tick species (D. reticulatus, H. concinna and I. ricinus). The rate of co-infections was highest in I. ricinus (20/27), while this tick species harbored the broadest range of co-infection combinations, with dual, triple and a quadruple infection(s) being detected.

First Detection of Spotted Fever Group Rickettsiae in Ticks in Serbia

Ticks can transmit multiple pathogenic bacteria responsible for diseases in animals and humans such as Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and spotted fever group Rickettsia sp. The current study aimed to investigate the presence of Rickettsiae in ticks collected from seven localities in Serbia. One hundred thirty-one (131) questing ticks belonging to 5 tick species (Dermacentor marginatus, Dermacentor reticulatus, Haemaphysalis punctata, Haemaphysalis Concinna, and Ixodes ricinus) were collected in 2007 and 2009. Ticks were tested by polymerase chain reaction, amplifying gltA, ompA, and 17-kd genes, and sequencing analysis, revealing the presence of Rickettsia helvetica and Rickettsia monacensis in I. ricinus ticks only (infection rates 7.7% and 15.4% for R. helvetica and R. monacensis, respectively). R. helvetica has been isolated from I. ricinus ticks and has been implicated in fatal perimyocarditis. R. monacensis was first identified in I. ricinus samples collected in Germany and has recently been implicated in human infection. The results of the current study make fundamental the need to evaluate the incidence of infection with R. helvetica and R. monacensis among the resident population.

Phylogenetic relationships among Praini (Hymenoptera: Braconidae: Aphidiinae) aphid parasitoids, with redescription of two species

Phylogenetic relationships among four genera and 25 species of the tribe Praini (Braconidae: Aphidiinae) were investigated on the basis of 15 characters (13 morphological and two life history characters) using parsimony analysis. Areopraon Mackauer and Pseudopraon Starý are basal within the tribe. Both genera include species in which the external and internal types of pupation exist simultaneously [for example, Pseudopraon mindariphagum Starý, Areopraon lepelleyi (Waterston) and A. pilosum Mackauer)]. It can therefore be asserted that the external type of pupation behavior in the Praini probably originated in the polymorphic pupation behavior of ancient genera such as Pseudopraon and Areopraon. The genera Areopraon, Pseudopraon, and Dyscritulus Hincks form a monophylum separate from Praon. Areopraon is not retrieved as monophyletic. Species of the genus Praon Haliday possess conical apical spines on the top of the ovipositor sheath as an apomorphic character state. Within the genus Praon, we recognized the following closely related species groups: Parapraon + Praon dorsale-yomenae; and Praon rosaecola. Two Praini species are redescribed. Mesopraon Starý is a new synonym of Areopraon. Areopraon silvestre (Starý) and Areopraon helleni (Starý) are new combinations. A key to the recent Praini genera is given.

Detection of Borrelia-specific 16S rRNA sequence in total RNA extracted from Ixodes ricinus ticks

Para a deteccao de especies de Borrelia em carrapatos, desenvolveu-se a tecnica da transcricao reversa, seguida da reacao em cadeia da polimerase (RT-PCR). A tecnica baseou-se na amplificacao de 552 bases de nucleotideos de 16S rRNA, utilizando-se primers especificos de Borrelia. O RNA total extraido de amostras de carrapatos Ixodes ricinus foi usado como modelo. Verificou-se maior sensibilidade da RT-PCR, para a deteccao de Borrelia, em comparacao com a microscopia de campo escuro padrao. A especificidade da tecnica foi confirmada por clonagem e sequenciamento dos 552 pares de base obtidos. A analise filogenetica das sequencias obtidas revelou que pertencem a B. lusitaniae e genospecies B. afzelii. A RT-PCR apresentada neste trabalho podera ser muito util como teste de triagem para detectar a presenca do patogeno. Especialmente quando em investigacoes, e necessaria a extracao total de RNA de carrapatos.

Molecular characterization of Borrelia burgdorferi sensu lato strains isolated in the area of Belgrade, Serbia

This is the first report of the molecular characterization and identification of Borrelia burgdorferi sensu lato strains isolated in Serbia. Isolates A1, A2 and M1, from Ixodes ricinus, belong to Borrelia burgdorferi sensu stricto, while isolate K1 from Apodemus flavicollis is a mixture of Borrelia afzelii and B. burgdorferi s.s.

Assessment of the risk of contracting Lyme disease in areas with significant human presence

In order to describe seasonal changes in Lyme diseases risk rate at three localities in Serbia, during the period of 2003-2005, a total of 1542 Ixodes ricinus ticks (493 nymphs, 525 females and 524 males) were examined. The prevalence of Borrelia burgdorferi in Ixodes ricinus ticks at the Bovan Lake County were higher than the average for European localities (45.9% for adults and 18.8% for nymphs). In Mt. Avala and Kljajicevo counties adults and nymphs were, respectively, infected at the following percentages: 26.3, 10.7; 16.2 and 7.6%. The outcome indicates a relatively high risk of the contracting Lyme disease in all investigates areas.