Survival of Off-Host Rhipicephalus (Boophilus) annulatus (Acari: Ixodidae) Larvae in Study Arenas in Relation to Climatic Factors and Habitats in South Texas, USA

The cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say), is an economically destructive arthropod because of its ability to vector bovine babesiosis. Cattle fever ticks can spend more than 90% of their life cycle as questing larvae, but the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host larvae in nature. The study was conducted in a south Texas pasture over a 20-mo period, during which time larval populations were surveyed and ambient weather variables - relative humidity and temperatures – were recorded. Oviposition success and larval survival varied between cattle fever tick cohorts and was affected by relative humidity and canopied (with tree cover) versus exposed habitat. The results show that relative humidity and the interaction of relative humidity and inhabiting canopied habitats play a key role in oviposition success. Additionally, canopied habitats have a positive influence on off-host larval survival in the spring and summer

The acaricidal effect of peracetic acid against Boophilus annulatus and Argas persicus

The acaricidal activity of peracetic acid, PAA, against the cattle tick, Boophilus annulatus, and the fowl tick, Argas persicus was tested using filter paper contact bioassay. PAA had a great potential as acaricide and its effectiveness increased with increasing concentration and exposure time. Two minutes after treatment with 0.5%, PAA induced 100% mortality of both tick species and LC50 values for cattle and fowl ticks, after treatment for 30 min, were 0.06 and 0.05%, respectively. Following treatment with 0.25%, the LT50 values were 0.02 and 3.12 min, respectively. Furthermore, the detrimental effect of PAA against cattle tick extended beyond the adult stage, it significantly prolonged the preoviposition period, shortened the oviposition period, and decreased the mean number of the layed eggs, such parameters were 14.75 and 6.57 days, as well as 457.50, respectively, after treatment with 0.25% of PAA. Therefore, PAA is highly effective when used at lower doses and short exposure time. The high speed of killing ticks is very important for avoidance of the hazard ensued by pathogen transmission in the course of delayed mortality caused by the currently used acaricides

THE BIOLOGY OF THE TROPICAL CATTLE TICK AND OTHER SPECIES OF TICK IN PUERTO RICO, WITH NOTES ON THE EFFECTS ON TICKS OF ARSENICAL DIPS

For many years the presence of the tropical cattle tick, Boophilus annulatus microplus (Can.) (australis Fuller), in Puerto Rico has been a serious impediment to the development of the cattle industry in that island. In addition to heavy losses occasioned by tick infestation alone, the role of these ectoparasites in the transmission of tick fever of cattle has resulted in enormous losses and has presented an obstacle to the introduction of the better breeds of non-immune stock from tick-free areas

Homology among the autosomal chromosomes of \u3ci\u3eBoophilus annulatus\u3c/i\u3e (Say) and \u3ci\u3eB. microplus\u3c/i\u3e (Canestrini)

Autosomes of Boophilus annulatus and B. microplus were compared using C- and G-bands to establish the degree of homology. Karyotypes of both species consisted of 20 autosomes and an XX:XO sex determination system with the X being the largest chromosome. All chromosomes of B. annulatus were acrocentric with heterochromatin limited to centromeric regions. The B. microplus karyotype was acrocentric with one band of noncentromeric heterochromatin occurring in three chromosome pairs. Interspecific comparisons indicated seven pairs of G-band homologous autosomes and three G-band homologous pairs when added interstitial heterochromatin was considered. The number three chromosome of both species showed variation in length at an area of extreme constriction associated with the nucleolar organizer region

In-Vitro Assessment of the Acaricidal Properties of Artemisia annua and Zataria multiflora Essential Oils to Control Cattle Ticks

Background: The aim of this study was to investigate the ‘acaricidal effect' of Zataria multiflora and Ar­temisia annua essential oils on Rhipicephalus (Boophilus) annulatus.Methods: This study was carried out in 2009 in the Laboratory of Parasitology of the Faculty of Veteri­nary Medicine of Shahrekord University, west central Iran. Six dilutions (5, 10, 20, 40, 60 and 80 µL/cm3) of both essential oils were used against engorged female R. (Boophilus) annula­tus ticks using an in vitro immersion method. The mortality rates for each treatment were re­corded 6, 15 and 24 hours post inoculation (hpi). Mortality rate was analyzed using Repeated Meas­ures Analysis of Variance, and compari­son of means was carried out using General Linear Models Procedure.Results: The mortality rate caused by different dilutions of Z. multiflora essential oil ranged from 26.6% (using 10 µL/cm3) to 100% (using 40 µL/cm3) and for A. annua essential oil it was 33.2 to 100% (using 20 and 80 µL/cm3, respectively) by the end of the experiment (36 hpi). No mortality was recorded for the non-treated control group or for dilutions less than 5 and 10 µL/cm3 using Zataria and Artemisia essential oils, respectively. For Z. multiflora mortality peaked at 15 hpi for all concentrations other than 20 µL/cm3 and took 24 h to achieve its maximum effect while for A. an­nua the two highest concentrations needed 24 hpi to reach their full effect. In addition, essen­tial oils applied at more than 20 and 60 µL/cm3 caused 100% egg-laying failure in engorged fe­male ticks by Zataria and Artemisia, respectively while no failure was observed for the non-treated control group. The mortality rate in both botanical acaricides was dose-dependent.Conclusion: Both these medicinal plants have high potential acaricidal effects on the engorged stage of R. (Boophilus) annulatus in vitro

Survival of off-host unfed Rhipicephalus (Boophilus) annulatus (Acari: Ixodidae) larvae in study arenas in relation to climatic factors and habitats in South Texas, USA

The cattle fever tick, Rhipicephalus annulatus (Say), is an economically destructive arthropod because of its ability to vector bovine babesiosis. Cattle fever ticks can spend more than 90% of their life cycle as questing larvae, but the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host larvae in nature. The study was conducted in a south Texas pasture over a 20-mo period, during which time larval populations were surveyed and ambient weather variables - relative humidity and temperatures - were recorded. Oviposition success and larval survival varied between cattle fever tick cohorts and was affected by relative humidity and canopied (with tree cover) versus exposed habitat. The results show that relative humidity and the interaction of relative humidity and inhabiting canopied habitats play a key role in oviposition success. Additionally, canopied habitats have a positive influence on off-host larval survival in the spring and summer