993 resultados para TICKS ACARI


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Tetranychus evansi Baker and Pritchard and Tetranychus urticae Koch (Acari: Tetranychidae) are important pests of Solanaceae in many countries. Several studies have demonstrated that T. urticae is an acceptable prey to many predatory mites, although the suitability of this prey depends on the host plant. T. evansi, has been shown to be an unfavorable prey to most predatory mites that have been tested against it. The predator Phytoseiulus fragariae Denmark and Schicha (Acari: Phytoseiidae) has been found in association with the two species in Brazil. The objective of this work was to compare biological parameters of P. fragariae on T. evansi and on T. urticae as prey. The study was conducted under laboratory conditions at 10, 15, 20, 25 and 30 degrees C. At all temperatures, survivorship was lower on T. evansi than on T. urticae. No predator reached adulthood at 10 degrees C on the former species; even on the latter species, only about 36% of the predators reached adulthood at 10 degrees C. For both prey, in general, duration of each life stage was shorter, total fecundity was lower and intrinsic rate of population increase (r(m) ) was higher with increasing temperatures. The slower rate of development of P. fragariae on T. evansi resulted in a slightly higher thermal requirement (103.9 degree-days) on that prey than on T. urticae (97.1 degree-days). The values of net reproduction rate (R-0), intrinsic rate of increase (r (m) ) and finite rate of increase (lambda) were significantly higher on T. urticae, indicating faster population increase of the predator on this prey species. The highest value of r (m) of the predator was 0.154 and 0.337 female per female per day on T. evansi and on T. urticae, respectively. The results suggested that P. fragariae cannot be considered a good predator of T. evansi.

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To determine the effect of storage on fungal survival, mummified cadavers of the cassava green mite pathogen, Neozygites tanajoae were placed at different conditions of temperature and relative humidity. The best condition for long-term preservation was -10 degrees C. At this condition, the fungus retained viability for 10 years when the experiment was terminated, with a decrease in sporulation with time. Cadavers placed at 4 degrees C and 5% RH sporulated for 2 years, while the fungus survived for only 7 days at 25 degrees C and 50% RH.

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A redescription of Lasioseius floridensis Berlese, 1916 is presented based on examination with descriptive notes of primary type material in the Berlese Collection and on a study of specimens collected from gerbera leaves in Mogi das Cruzes, State of Sao Paulo, Brazil representing all postembryonic stages. This species was originally described from Lake City, Florida, USA, where it was collected from moss; it is considered a senior synonym of Lasioseius arboreus Chant, 1963 (new synonymy) and Lasioseius fimetorum Karg, 1971 (new synonymy), based on examination of primary type material of the latter two species. Examination of other primary type material also indicated that Lasioseius sugawarai Ehara, 1964 is a senior synonym of Lasioseius tridentatus Baker, Delfinado & Abbatiello, 1976 (new synonymy). Placement of L. floridensis among other of the ca 150 species of Lasioseius, based on available keys, and the need for more detailed descriptions of species of genera such as Lasioseius, confirmed by examination of their primary type material, are discussed.

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In a series of tritrophic-level interaction experiments, the effect of selected host plants of the spider mites, Tetranychus evansi and Tetranychus urticae, on Neozygites floridana was studied by evaluating the attachment of capilliconidia, presence of hyphal bodies in the infected mites, mortality from fungal infection, mummification and sporulation from fungus-killed mite cadavers. Host plants tested for T. evansi were tomato, cherry tomato, eggplant, nightshade, and pepper while host plants tested for T. urticae were strawberry, jack bean, cotton and Gerbera. Oviposition rate of the mites on each plant was determined to infer host plant suitability while host-switching determined antibiosis effect on fungal activity. T. evansi had a high oviposition on eggplant, tomato and nightshade but not on cherry tomato and pepper. T. urticae on jack bean resulted in a higher oviposition than on strawberry, cotton and Gerbera. Attachment of capilliconidia to the T. evansi body, presence of hyphal bodies in infected T. evansi and mortality from fungal infection were significantly higher on pepper, nightshade and tomato. The highest level of T. evansi mummification was observed on tomato. T. evansi cadavers from tomato and eggplant produced more primary conidia than those from cherry tomato, nightshade and pepper. Switching N. floridana infected T. evansi from one of five Solanaceous host plants to tomato had no prominent effect on N. floridana performance. For T. urticae, strawberry and jack bean provided the best N. floridana performance when considering all measured parameters. Strawberry also had the highest primary conidia production. This study shows that performance of N. floridana can vary with host plants and may be an important factor for the development of N. floridana epizootics. (C) 2011 Elsevier Inc. All rights reserved.

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A new genus and new species of the mite family Eriophyidae (Phyllocoptinae), namely Cothrix erugata n. sp. et n. gen., is described from Heliconia stricta Huber (Heliconiaceae). In addition, one new genus and two new species of Diptilomiopidae, namely Rhyncadicrus asperulus n. sp. et n. gen. from banana, Musa acuminata Colla x Musa balbisiana Colla (genomic group AAB) (Musaceae) and Catarhinus granatus n. sp. from Heliconia bihai L., are described and illustrated. The mites were collected in the State of Pernambuco, Northeastern Brazil. All were vagrants on the lower leaf surfaces of their host plants and no visible damage symptoms were observed.

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A new species of eriophyoid mite, belonging in the genus Abacarus Keifer (Eriophyidae), causing damage to sugarcane, Saccharum officinarum L. (Poaceae), in Costa Rica is illustrated and described. Abacarus doctus n. sp. is the only eriophyoid species recorded so far with a tibial seta (l`) on the second pair of legs, an unexpected characteristic observed for the first time in the superfamily Eriophyoidea. Remarks on the phylogenetic and taxonomical aspects related to the presence of this seta are presented. Damage symptoms caused by this mite are presented as well as a key for Abacarus species described from sugarcane. In addition, the need to apply biosecurity procedures during sugarcane germplasm exchange to avoid dissemination of the new mite species is discussed.

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Tetranychus palmarum sp.nov., a new red spider mite from the African oil palm, is described and figured.

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A new genus and two new species of eriophyoid mites in the family Diptilomiopidae associated with Spondias mombin L. (Anacardiaceae), namely Solivagus n. gen. alpha n. sp. and Davisella spondias n. sp., are described. In addition, a new species of Eriophyidae associated with Eugenia uniflora L. (Myrtaceae), namely Dichopelmus ibapitanga n. sp., is described and Aculus pitangae Boczek & Davis, also from E. uniflora, is redescribed including a description of the male, and its classification is discussed. All material studied was collected in the State of Pernambuco, Northeastern Brazil.

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Two new genera and five new species of Eriophyidae from forest trees in southern Brazil are described, namely: Juxtacolopodacus n. gen., Juxtacolopodacus phalakros n. sp. from Mollinedia clavigera Tul. (Monimiaceae); Procalacarus perporosus n. sp., from Randia armata (Sw.) (Rubiaceae); Scolotosus Flechtmann & Keifer, n. gen., Scolotosus centrolobii Flechtmann & Keifer, n. sp., from Centrolobium robustum Mart. (Leguminosae); Scolotosus hartfordi n. sp., from Centrolobium tomentosum Guill. (Leguminosae), and Metaculus tanythrix n. sp., from Dicksonia sellowiana Hook. (Dicksoniaceae).

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Two new Tetranychidae (Prostigmata) mites are described from Brazil Monoceronychus tchecensis n. sp., a bryobiine collected from weeping fingergrass, Eustachys distichophylla (Lag.) Nees (Poaceae), in the State of Rio Grande do Sul; and Oligonychus fileno n. sp., a tetranychine collected from grape, Vitis vinifera L. (Vitaceae), in the State of Minas Gerais. Monoceronychus tchecensis n. sp. is the second species in this genus described from South America. In addition to the description of these new species, the tetranychine Eotetranychus smithi Pritchard and Baker, 1955 was recorded for the first time for South America.

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Aceria inusitata Britto and Navia n. sp. (Acari: Eriophyidae) is described from protogynes, deutogynes and two forms of males occurring under a ""patches of webbing"" from ""pau-brasil,"" Caesalpinia echinata L. (Caesalpiniaceae), leaves. This is the first example of a deuterogynous eriophyid mite in tropical regions with two forms of males, one resembling the protogyne and the other the deutogyne. In addition, biological observations are presented. Aberoptus cerostructor Flechtmann, is given a new generic assignment, Aceria cerostructor n. comb.

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Ticks affect human and animal health both directly by their blood feeding and indirectly by transmission of many disease-causing bacteria, such as Rickettsia, Ehrlichia, Borrelia, Coxiella, Cowdria, Anaplasma, Aegyptionella, and Tularemia, as well as many viruses (Piesman and Gage, 1996). In addition to these infectious agents, ticks harbor bacterial endosymbionts, such as Wolbachia persica, which was first isolated from the soft tick now classified as Argus arboreus (Suitor and Weiss, 1961).

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Most populations and some species of ticks of the genera Boophilus (5 spp.) and Rhipicephalus (ca. 75 spp.) cannot be distinguished phenotypically. Moreover, there is doubt about the validity of species in these genera. I studied the entire second internal transcribed spacer (ITS 2) rRNA of 16 populations of rhipicephaline ticks to address these problems: Boophilus,microplus from Australia, Kenya, South Africa and Brazil (4 populations); Boophilus decoloratus from Kenya; Rhipicephalus appendiculatus from Kenya, Zimbabwe and Zambia (7 populations); Rhipicephalus zambesiensis from Zimbabwe (3 populations); and Rhipicephalus evertsi from Kenya. Each of the 16 populations had a unique ITS 2, but most of the nucleotide variation occurred among species and genera. ITS 2 rRNA can be used to distinguish the populations and species of Boophilus and Rhipicephalus studied here. Little support was found for the hypothesis that B. microplus from Australia and South Africa are different species. ITS 2 appears useful for phylogenetic inference in the Rhipicephalinae because in genetic distance, maximum likelihood, and maximum parsimony analyses, most branches leading to species had >95% bootstrap support. Rhipicephalus appendiculatus and R, zambeziensis are closely related, yet their ITS 2 sequences could be distinguished unambiguously. This lends weight to a previous proposal that Rhipicephalus sanguineus and Rhipicephalus turanicus, and Rhipicephalus pumlilio and Rhipicephalus camicasi, respectively, are conspecific, because each of these pairs of species had identical sequences for ca. 250 bp of ITS 2 rRNA.

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We describe the isolation and characterisation of two putatively new acetylcholinesterase genes from the African cattle ticks Boophilus decoloratus and Rhipicephalus appendiculatus. The nucleotide sequences of these genes had 93% homology to each other and 95% and 91% identity, respectively, to the acetylcholinesterase gene from an Australian strain of another cattle tick, Boophilus microplus. Translation of the nucleotide sequences revealed putative amino acids that are essential for acetylcholinesterase activity: the active site serine, and the histidine and glutamate residues that associate with this serine to form the catalytic triad. All known acetylcholinesterases have three sets of cysteines that form disulfide bonds; however, the acetylcholinesterase genes of these three species of ticks encode only two sets of cysteines. Acetylcholinesterases of B. microplus from South Africa, Zimbabwe, Kenya and Mexico had 98-99% identity with acetylcholinesterase from B. microplus from Australia, whereas acetylcholinesterase from B. microplus from Indonesia was identical to that from Australia. Preliminary phylogenetic analyses surprisingly indicate that the acetylcholinesterases of ticks are closer phylogenetically to acetylcholinesterases of vertebrates than they are to those of other arthropods. (C) 1999 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.

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