Snežana Tomanović

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.

Acaricidal Effect of Different Diatomaceous Earth Formulations Against Tyrophagus putrescentiae (Astigmata: Acaridae) on Stored Wheat

ABSTRACT Laboratory bioassays were conducted to evaluate the effect of different diatomaceous earth (DE) formulations against adults and immature stages of the stored-product mite species Tyrophagus putrescentiae (Schrank). Five DE formulations were used in the tests: SilicoSec, PyriSec, Insecto, Protect-It, and DEA-P. The tests were conducted at 25°C and 75% RH, on wheat, Triticum aestivum L., treated with DEs at two dose rates, 0.2 and 0.5 g/kg. The mortality of mite individuals was measured after 5 d of exposure, and after 30 d the treated wheat was checked for T. putrescentiae offspring. Significant differences were noted among the DEs tested. Application of the lowest dose rate (0.2 g/kg) provided mortality of both adults and immatures that exceeded 78%, whereas the respective data for 0.5 g/kg were almost in all cases 100%. The adults of T. putrescentiae were more tolerant to DEs than the immature stages. Generally, PyriSec was the most effective against adults. Progeny production was dramatically reduced with the increase of dose. The results of the present work indicate that T. putrescentiae can be effectively controlled by DEs on wheat, at dose rates as low as 0.2 g/kg.

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.

Contributions to the morphology and phylogeny of the newly discovered bat tick species, Ixodes ariadnae in comparison with I. vespertilionis and I. simplex

BackgroundRecently a new hard tick species, Ixodes ariadnae has been discovered, adding to the two known ixodid tick species (I. vespertilionis and I. simplex) of bats in Europe.FindingsScanning electron microscopic comparison of adult females of these species shows morphological differences concerning the palps, the scutum, the Haller’s organ, the coxae, as well as the arrangement and fine structure of setae. Molecular analysis of 10 geographically different isolates revealed 90-95% sequence homology in the 12S and 16S rDNA genes of bat tick species. Based on 12S rDNA sequences, genotypes of I. ariadnae clustered closest to I. simplex, whereas according to their 16S rDNA gene they were closest to I. vespertilionis. The subolesin gene of I. ariadnae had only 91% sequence homology with that of I. ricinus, and is the longest known among hard tick species.ConclusionsThe present study illustrates the morphology and clarifies the phylogenetic relationships of the three known bat tick species that occur in Europe. According to its subolesin gene I. ariadnae may have a long evolutionary history.

East and west separation of Rhipicephalus sanguineus mitochondrial lineages in the Mediterranean Basin

BackgroundRhipicephalus sanguineus belongs to a complex of hard tick species with high veterinary-medical significance. Recently, new phylogenetic units have been discovered within R. sanguineus, which therefore needs taxonomic revision. The present study was initiated to provide new information on the phylogeography of relevant haplotypes from less studied regions of Europe and Africa. With this aim, molecular-phylogenetic analyses of two mitochondrial markers were performed on 50 ticks collected in Hungary, the Balkans, countries along the Mediterranean Sea, Kenya and Ivory Coast.ResultsIn the “temperate lineage” of R. sanguineus, based on cytochrome c oxidase subunit 1 (cox1) and 16S rRNA genes, Rhipicephalus sp. I was only found in the eastern part of the Mediterranean Basin (with relatively homogenous haplotypes), whereas Rhipicephalus sp. II occurred in the middle-to-western part of this region (with phylogenetically dichotomous haplotypes). Ticks identified as R. leporis (based on morphology and cox1 gene) were found in Kenya and Ivory Coast. These clustered phylogenetically within R. sanguineus (s.l.) (“tropical lineage”).ConclusionsIn the Mediterranean Basin two mitochondrial lineages of R. sanguineus, i.e. Rhipicephalus sp. I and Rhipicephalus sp. II exist, which show different geographical distribution. Therefore, data from this study confirm limited gene flow between Rhipicephalus sp. I and Rhipicephalus sp. II, but more evidence (analyses of nuclear markers, extensive morphological and biological comparison etc.) are necessary to infer if they belong to different species or not. The phylogenetic relationships of eastern and western African ticks, which align with R. leporis, need to be studied further within R. sanguineus (s.l.) (“tropical lineage”).

Presence of Leishmania and Brucella Species in the Golden Jackal Canis aureus in Serbia

The golden jackal Canis aureus occurs in south-eastern Europe, Asia, the Middle East, the Caucasus, and Africa. In Serbia, jackals neared extinction; however, during the last 30 years, the species started to spread quickly and to increase in number. Few studies in the past have revealed their potential role as carriers of zoonotic diseases. Animal samples were collected over a three-year period (01/2010–02/2013) from 12 sites all over Serbia. Of the tissue samples collected, spleen was chosen as the tissue to proceed; all samples were tested for Leishmania species and Brucella species by real-time PCR. Of the 216 samples collected, 15 (6.9%) were positive for Leishmania species, while four (1.9%) were positive for B. canis. The potential epidemiologic role of the golden jackal in carrying and dispersing zoonotic diseases in Serbia should be taken under consideration when applying surveillance monitoring schemes.

Contributions to the phylogeny of Ixodes (Pholeoixodes) canisuga, I. (Ph.) kaiseri, I. (Ph.) hexagonus and a simple pictorial key for the identification of their females

BackgroundIn Europe, hard ticks of the subgenus Pholeoixodes (Ixodidae: Ixodes) are usually associated with burrow-dwelling mammals and terrestrial birds. Reports of Pholeoixodes spp. from carnivores are frequently contradictory, and their identification is not based on key diagnostic characters. Therefore, the aims of the present study were to identify ticks collected from dogs, foxes and badgers in several European countries, and to reassess their systematic status with molecular analyses using two mitochondrial markers.ResultsBetween 2003 and 2017, 144 Pholeoixodes spp. ticks were collected in nine European countries. From accurate descriptions and comparison with type-materials, a simple illustrated identification key was compiled for adult females, by focusing on the shape of the anterior surface of basis capituli. Based on this key, 71 female ticks were identified as I. canisuga, 21 as I. kaiseri and 21 as I. hexagonus. DNA was extracted from these 113 female ticks, and from further 31 specimens. Fragments of two mitochondrial genes, cox1 (cytochrome c oxidase subunit 1) and 16S rRNA, were amplified and sequenced. Ixodes kaiseri had nine unique cox1 haplotypes, which showed 99.2–100% sequence identity, whereas I. canisuga and I. hexagonus had eleven and five cox1 haplotypes, respectively, with 99.5–100% sequence identity. The distribution of cox1 haplotypes reflected a geographical pattern. Pholeoixodes spp. ticks had fewer 16S rRNA haplotypes, with a lower degree of intraspecific divergence (99.5–100% sequence identity) and no geographical clustering. Phylogenetic analyses were in agreement with morphology: I. kaiseri and I. hexagonus (with the similar shape of the anterior surface of basis capituli) were genetically more closely related to each other than to I. canisuga. Phylogenetic analyses also showed that the subgenus Eschatocephalus (bat ticks) clustered within the subgenus Pholeoixodes.ConclusionsA simple, illustrated identification key is provided for female Pholeoixodes ticks of carnivores (including I. hexagonus and I. rugicollis) to prevent future misidentification of these species. It is also shown that I. kaiseri is more widespread in Europe than previously thought. Phylogenetic analyses suggest that the subgenus Pholeoixodes is not monophyletic: either the subgenus Eschatocephalus should be included in Pholeoixodes, or the latter subgenus should be divided, which is a task for future studies.