Brevipalpus Phoenicis Research Articles

Status of Aceria guerreronis Keifer (Acari: Eriophyidae) as a Pest of Coconut in the State of Sao Paulo, Southeastern Brazil

The coconut mite, Aceria guerreronis Keifer, is one of the main pests of coconut palms (Cocos nucifera) in northeastern Brazil. The objective of this study was to evaluate the levels of the coconut mite and other mites on coconut palms in the state of São Paulo and to estimate the possible role of predatory mites in the control of this pest. The effect of cultivated genotypes and sampling dates on the mite populations was also estimated. We sampled attached fruits, leaflets, inflorescences, and fallen fruits. The coconut mite was the main phytophagous mite found on attached and fallen fruits, with average densities of 110.0 and 20.5 mites per fruit, respectively. The prevalent predatory mites on attached and fallen fruits were Proctolaelaps bulbosus Moraes, Reis & Gondim Jr. and Proctolaelaps bickleyi (Bram), both Melicharidae. On leaflets, the tenuipalpids Brevipalpus phoenicis (Geijsks) and Tenuipalpus coyacus De Leon and the tetranychid Oligonychus modestus (Banks) were the predominant phytophagous mites. On both leaflets and inflorescences, the predominant predatory mites belonged to the Phytoseiidae. Neoseiulus baraki (Athias-Henriot) and Neoseiulus paspalivorus (De Leon), predators widely associated with the coconut mite in northeastern Brazil and several other countries, were not found. The low densities of the coconut mite in São Paulo could be related to prevailing climatic conditions, scarcity of coconut plantations (hampering the dispersion of the coconut mite between fields), and to the fact that some of the genotypes cultivated in the region are unfavorable for its development.

Biological notes and risk status of <i>Brevipalpus phoenicis</i> (Geijskes, 1939) (Acari: Tenuipalpidae) in New Zealand

The status of the tenuipalpid mite Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae) in New Zealand was previously uncertain. New collection records suggest that this mite is established, at least in the northern North Island. Brevipalpus phoenicis is known to vector a number of plant diseases caused by Rhabdoviriidae (Mononegavirales), including some known to cause serious damage to food crops such as Citrus leprosis virus (CiLV), Passion fruit green spot virus (PFGSV) and Coffee ringspot virus (CoRSV). None of the diseases ectored by this mite are known to be present in New Zealand. Consequently B. phoenicis should still be considered of concern to New Zealand’s biosecurity under some circumstances.

Citrus leprosis virus C Naturally Infecting Commelina benghalensis, a Prevalent Monocot Weed of Citrus Orchards in Brazil.

There are two bacilliform, rhabdo-like viruses that cause citrus leprosis: Citrus leprosis virus C (CiLV-C), which accumulates in the cytoplasm of infected cells, and Citrus leprosis virus nuclear type (CiLV-N), which accumulates in their nucleus. The first one, the prototype of the new genus Cilevirus, is prevalent and occurs in several countries of the American continent, from Argentina to Mexico (1). The second type, still a tentative member of the Rhabdoviridae family, is of rare occurrence, with a few reports in Brazil and one in Panama (1). Leprosis is particularly important to the Brazilian citrus industry because of the 60 to 80 million dollars spent yearly for the control of Brevipalpus phoenicis (Geijskes, 1939) (Acari: Tenuipalpidae), the vector of the virus (1). For decades, the disease was considered unique to citrus plants; however, greenhouse experiments conducted in the 1990s demonstrated the mechanical transmission of CiLV-C to noncitrus plants (1). Years later, researchers were able to transmit the virus to nonrutaceous hosts using viruliferous mites (1,4). Recently, León et al. (2) reported the occurrence of the first noncitrus plant naturally infected by CiLV-C, the rutaceous Swinglea glutinosa Blanco (Merr.). Tropical spiderworts (Commelina benghalensis L.; Commelinaceae) are monocot weeds commonly found in citrus orchards in Brazil. In a survey conducted in orchards with high incidences of leprosis in the municipalities of Borborema and São José do Rio Preto, State of Sao Paulo, Brazil, tropical spiderworts were found exhibiting necrotic spots with a yellow halo in green leaves and green spots with necrotic center in senescent leaves. Since these symptoms are similar to those caused by CiLV-C in citrus, symptomatic plants were collected and subjected to transmission electron microscopy analyses and reverse transcription-PCR using primers that specifically amplify a region within the putative movement protein gene of the virus (3). Bacilliform virus particles and typical inclusions were seen in the lesions. Bands of the expected 344 bp size were seen in agarose gels of symptomatic samples only. The analysis of the consensus sequence showed 100% identity with CiLV-C sequence available in the GenBank (Accession No. YP_654542.1). Experimental transmission of CiLV-C by B. phoenicis reproduced the lesions in inoculated tropical spiderwort. Also, the virus could be easily transmitted back from C. benghalensis to sweet orange plants. Our data show that this widespread weed is the first monocot as a natural host for CiLV-C. Since tropical spiderwort is a host for B. phoenicis and symptomatic plants were found in two municipalities 130 km apart from each other, it is possible that this weed may serve as reservoir for the virus and play a relevant role in the spread of the disease in the field, but this issue still needs to be addressed in further experiments.

In vitro expression and antiserum production against the movement protein of Citrus leprosis virus C (CiLV-C)

Citrus leprosis, caused by Citrus leprosis virus C (CiLV-C), is currently considered the most important viral disease in the Brazilian citrus industry due to the high costs required for the chemical control of its vector, the mite Brevipalpus phoenicis. The pathogen induces a non-systemic infection and the disease is characterized by the appearance of localized lesions on citrus leaves, stems and fruits, premature fruit and leaf drop and dieback of stems. Attempts were made to promote in vitro expression of the putative cell-to-cell movement protein of CiLV-C in Escherichia coli and to produce a specific polyclonal antibody against this protein as a tool to investigate the virus-plant-vector relationship. The antibody reacted strongly with the homologous protein expressed in vitro by ELISA, but poorly with the native protein present in leaf lesion extracts from sweet orange caused by CiLV-C. Reactions from old lesions were more intense than those from young lesions. Western blot and in situ immunolocalization assays failed to detect the native protein. These results suggest low expression of the movement protein (MP) in host tissues. Moreover, it is possible that the conformation of the protein expressed in vitro and used to produce the antibody differs from that of the native MP, hindering a full recognition of the latter.

Acarofauna em cultivo de pinhão-manso e plantas espontâneas associadas

O objetivo deste trabalho foi identificar ácaros na cultura de pinhão-manso e em espécies de plantas espontâneas associadas. Para isso, foram avaliadas a riqueza e a abundância de ácaros em plantas de pinhão-manso e em 14 espécies de plantas espontâneas associadas. As amostragens foram realizadas por meio de coletas mensais de folhas de plantas de pinhão-manso e de plantas espontâneas, nas entrelinhas do cultivo. Foram encontradas quatro espécies de ácaros predadores - Amblyseius tamatavensis, Paraphytoseius multidentatus, Typhlodromalus aripo e Typhlodromalus clavicus -, com potencial para uso no controle biológico de ácaros-praga na cultura do pinhão-manso, e duas importantes espécies de ácaros fitófagos - Brevipalpus phoenicis e Tarsonemus confusus - desconhecidas como praga da cultura. Entre as plantas espontâneas avaliadas, quatro espécies - Hyptis suaveolens, Peltaea riedelii, Urochloa mutica e Andropogon gayanus - abrigam grande riqueza e abundância de ácaros predadores, enquanto oito destacaram-se pela diversidade de ácaros fitófagos.

Dinâmica da infestação de Brevipalpus phoenicis (Geijskes, 1939) (Acari:Tenuipalpidae) em pomares cítricos da Bahia, Brasil

Em duas regiões da Bahia - Litoral Norte (LN) e Recôncavo Baiano (RB) quantificaram-se a dinâmica espaço-temporal da infestação de plantas cítricas pelo ácaro Brevipalpus phoenicis. Dez pomares de cada região foram avaliados mensalmente (de abril de 2008 a fevereiro de 2011), nos quais 21 plantas tiveram três frutos/planta vistoriados com lupa de 10x para registrar a presença ou ausência do ácaro. A proporção média de plantas infestadas variou entre 0,38 e 1,0. Em frutos, a proporção mínima de infestação foi 0,10 e máxima de 0,73 no LN e 0,66 no RB. O processo de infestação foi sazonal, com mais unidades infestadas na primavera-verão (Nemenyi, p<0,05). A análise de densidade espectral mostrou a ocorrência de dois tipos de ciclos: um com período aproximado de 2 meses, possivelmente relacionado com a biologia do ácaro e outro anual, decorrente da interação vetor-hospedeiro-ambiente. Em ambas as regiões, a aleatoriedade caracterizou o padrão espacial da infestação do ácaro intra e interpomares. Não foram observados sintomas de leprose dos citros no RB.

Phytophagous mites – a potential threat to medicinal plants in Kerala, India

This article presents the results of a brief survey of mites infesting medicinal plants in the Kannur district of Kerala state in south India. Six species, damaging five species of important medicinal plants, were found. These species included Tetranychus urticae Koch (Tetranychidae), Brevipalpus phoenicis Geij. 1939 (Tenuipalpidae) and four Eriophyid species, Paratetra murrayae ChannaBasavanna 1966, Anthocoptes vitexae Mohanasundaram 1981, Aceria sp. nov. I and Aceria sp. nov. II and the host plants were Justicia adhatoda, Hibiscus rosasinensis, Murraya koenigii, Vitex negundo and Ixora coccinia, respectively. Mite-induced host damage, such as chlorosis, bud malformation, shoot deformity, leaf crinkling and reduction in leaf size, is discussed.

Towards new botanical pesticides: the toxic effect of Eremanthus goyazensis (Asteraceae) leaves essential oil against Brevipalpus phoenicis (Acari: Tenuipalpidae)

This work reports the chemical characterization of Eremanthus goyzensis essential oil and its toxic effect over Brevipalpus phoenicis. The essential oil displayed a major composition of sesquiterpenes (61.87%) including trans-caryophillene (26.81%) and germacrene-D (13.31%). The fumigation test indicated a promising bioactivity over adult B. phoenicis individuals at 24 h (2.03 μL/L of air) and 48 h (1.08 μL/L of air) of exposition. A brief discussion of essential oils composition and their singular role on the toxic effect over B. phoenicis is provided here. Our results may contribute to a new and profitable use of a species of Brazilian flora on agribusiness.

<p><strong>Asymmetry in the number of solenidia on tarsi II of </strong><strong><em>Brevipalpus </em></strong><strong>(Acari: Tenuipalpidae) populations from Argentina*</strong></p>

To verify the prevailing Brevipalpus species in citrus orchards affected by leprosis in Argentina, specimens of this genus were collected mainly from ‘Valencia’ and ‘Hamlin’ varieties of sweet orange plants from experimental and commercial plantations at Bella Vista, Corrientes Province, Concordia, Entre Rios Province and Saens Peña, Chaco Province. Examinations under light microscopy and scanning electron microscopy were carried out to identify the species based on external morphological characteristics. A mixture of typical Brevipalpus obovatus Donnadieu and Brevipalpus phoenicis (Geijskes) was found, with prevalence of the former (43.7 versus 27.2%) in the 327 adult females examined. However, 29% of the total number of females examined were atypical, having one solenidion (ù”) on one of tarsi II and two (ù’ and ù”) on the other, either left or right. To investigate whether this variation was also common elsewhere, several Brevipalpus populations of the obovatus species-group from Chile (Brevipalpus chilensis Baker), Brazil (B. obovatus and B. phoenicis), Costa Rica and Paraguay (B. phoenicis in both countries) were examined. Asymmetric numbers of tarsus II solenidia were found in 11 of the 1,993 examined adult female specimens of these populations. The results suggested a relation between the high proportion of asymmetric mites in Argentina and the occurrence of a mixed population of both B. obovatus and B. phoenicis; however, present knowledge about the apparently parthenogenetic system of reproduction of these species does not support the hypothesis that asymmetric mites could be the hybrids of those species. Thus, the factor leading to high proportions of asymmetric Brevipalpus in Argentina remains unknown.

<p><strong>Technical and economic evaluation of different types of control of </strong><strong><em>Brevipalpus phoenicis </em></strong><strong>(Acari: Tenuipalpidae) in citrus leprosies management*</strong></p>

The objective of this work was to evaluate the effect of acaricide applications and pruning of symptomatic branches in citrus leprosis management in Brazil. It was conducted in an orange plantation of the ‘Pera’ variety, grafted onto the ‘Cleopatra’ tangerine, in two seasons (2006–2007 and 2007–2008). The experimental design was randomized blocks in a factorial scheme consisting of the following factors: (A) acaricide, in three levels: spirodiclofen and cyhexatin applied in rotation, lime sulphur; no acaricides; (B) pruning to remove branches that showed symptoms of leprosis, with two levels: with pruning, without pruning. We carried out periodic assessments of Brevipalpus phoenicis (Geijskes) populations (vector of the leprosis virus), leprosis incidence and severity, fruit yield, and the economic feasibility of the applied strategies. Based on the results, we concluded that spirodiclofen and cyhexatin were more effective than lime sulphur in B. phoenicis control. Control with lime sulphur required more applications than spirodiclofen and cyhexatin in rotation, making it more expensive. Pruning of symptomatic branches used in isolation was not sufficiently effective to control leprosis and significantly increased control costs. Profits were higher when the control involved sprayings of spirodiclofen and cyhexatin in alternation, with or without pruning.

Resíduos de calda sulfocálcica sobre a eficiência de acaricidas no controle de Brevipalpus phoenicis

O objetivo do trabalho foi verificar a influência dos resíduos de calda sulfocálcica sobre a eficiência de acaricidas empregados no controle de Brevipalpus phoenicis. Inicialmente, o experimento foi instalado em um pomar de citros, em que foram selecionadas 10 plantas que continham frutos com verrugose. Realizou-se a aplicação de calda sulfocálcica (8g i.a. L-1 de água) em cinco plantas e as outras cinco plantas permaneceram sem aplicação de produto fitossanitário. Protegeram-se, com copos de plástico transparente de 500mL, 64 frutos nas plantas tratadas com calda e 64 frutos nas plantas não-tratadas, totalizando 128 frutos protegidos. Decorridos 30 dias da aplicação, os frutos foram colhidos e levados para o laboratório. Estes frutos foram parcialmente parafinados, deixando-se em cada fruto uma arena de 2,5cm de diâmetro com verrugose e sem parafina, delimitada com cola entomológica. Em seguida, procedeu-se à aplicação sobre os frutos em Torre de Potter dos seguintes acaricidas nas concentrações expressas em mg de ingrediente ativo por litro de água: propargite a 720mg, óxido de fenbutatina a 400mg, cyhexatin a 250mg, azocyclotin a 250mg, fenpyroximate a 50mg, dicofol a 960mg e dinocap a 738mg e a testemunha sem aplicação de acaricida. Após 1, 7 e 16 dias da aplicação, transferiram-se para cada fruto 10 ácaros B. phoenicis para avaliar a mortalidade. Constatou-se que os resíduos de calda sulfocálcica não prejudicaram a eficiência dos acaricidas avaliados no controle de B. phoenicis.

Mites fluctuation population on peach tree (Prunus persica (L.) Batsch) and in associated plants

Despite the importance of peach (Prunus persica (L.) Batsch) in Rio Grande do Sul, little is known about mites fluctuation population considered important to this crop. The objective of this study was to know the population diversity and fluctuation of mite species associated with Premier and Eldorado varieties in Roca Sales and Venâncio Aires counties, Rio Grande do Sul. The study was conducted from July 2008 to June 2009 when 15 plants were randomly chosen in each area. The plants were divided in quadrants and from each one a branch was chosen from which three leaves were removed: one collected in the apical region, another in the medium and the other in the basal region, totalizing 180 leaves/area. Five of the most abundant associated plants were collected monthly in enough amounts for the screening under the stereoscopic microscope during an hour. A total of 1,124 mites were found belonging to 14 families and 28 species. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836) and Mononychellus planki (McGregor, 1950) were the most abundant phytophagous mites, whereas Typhlodromalus aripo Deleon, 1967 and Phytoseiulus macropilis (Banks, 1904) the most common predatory mites. The period of one hour under stereoscopic microscope was enough to get a representative sample. In both places evaluated the ecologic indices were low, but little higherin Premier (H' 0.56; EqJ: 0.43) when compared to Eldorado (H' 0.53; EqJ 0.40). In Premier constant species were not observed and accessory only Brevipalpus phoenicis (Geijskes, 1939), T. ludeni and T. aripo. Higher abundance was observed in December and January and bigger amount in April. Already in Eldorado, T. ludeni and P. ulmi were constants. Greater abundance was observed in November and December, whereas grater richness in December and January. In both orchards were not found mites in buds. Tetranychus ludeni is the most abundant phytophagous mites with outbreak population in November, December and January and high predator diversity was observed on associated plants and on peach plants, indicating the existence of species mobility in peach orchard.

Effect of coconut palm proximities and Musa spp. germplasm resistance to colonization by Raoiella indica (Acari: Tenuipalpidae)

Although coconut (Cocos nucifera L.) is the predominant host for Raoiella indica Hirst (Acari: Tenuipalpidae), false spider mite infestations do occur on bananas and plantains (Musa spp. Colla). Since its introduction, the banana and plantain industries have been negatively impacted to different degrees by R. indica infestation throughout the Caribbean. Genetic resistance in the host and the proximity of natural sources of mite infestation has been suggested as two of the main factors affecting R. indica densities in Musa spp. plantations. Greenhouse experiments were established to try to determine what effect coconut palm proximities and planting densities had on R. indica populations infesting Musa spp. plants. Trials were carried out using potted Musa spp. and coconut palms plants at two different ratios. In addition, fourteen Musa spp. hybrid accessions were evaluated for their susceptibility/resistance to colonization by R. indica populations. Differences were observed for mite population buildup for both the density and germplasm accession evaluations. These results have potential implications on how this important pest can be managed on essential agricultural commodities such as bananas and plantains.

Selectivity of rynaxypyr for three species of phytoseiid mites relevant to coffee in Brazil.

Among the predaceous mites, those of the Phytoseiidae family are the most important and studied. The phytophagous mites Brevipalpus phoenicis (Geijskes, 1939) (Tenuipalpidae) and Oligonychus ilicis (McGregor, 1917) (Tetranychidae), on coffee trees ( Coffea spp.), are frequently found in combination with the predaceous mites Iphiseiodes zuluagai Denmark & Muma, 1972, Amblyseius herbicolus (Chant, 1959) and Euseius citrifolius Denmark & Muma, 1970, among others. The purpose of this research was to study the effects of the insecticide rynaxypyr (chlorantraniliprole 200 SC) on these three species of Phytoseiidae, relevant to coffee and citrus, following standard laboratory procedures. Mated female mites were exposed to fresh-dried residues on a glass surface, with 7 treatments, 5 mites per glass plate and 6 replicates, in a completely randomized experimental design. Each test lasted 8 days, with a daily count of the surviving females and of eggs laid. Rynaxypyr, in all tested concentrations (15, 30, 50, 100 and 500 mg a.i./liter of water), was selective for the studied species, A. herbicolus , I. zuluagai , and E. citrifolius . Overall the treatments resulted in low mortality rates and negligible impact on the reproduction. Therefore, based on IOBC standards, rynaxypyr can be classified as not harmful (Class 1), comparable to the agrochemical hexythiazox equivalent to a harmless standard of selectivity in the laboratory. Rynaxypyr is therefore a complement to programs of integrated pest management, to preserve the populations of predatory mites in crops of coffee and citrus, among others, in Brazil.

TABELA DE VIDA DE FERTILIDADE DE BREVIPALPUS PHOENICIS (GEIJSKES, 1939) (ACARI: TENUIPALPIDAE) EM DIFERENTES CULTIVARES DE CAFÉ (COFFEA SPP.)

RESUMO Este trabalho foi realizado visando elaborar a tabela de vida de fertilidade do ácaro da mancha-anular do cafeeiro, Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae), criado em folhas de quatro cultivares de café (‘Icatu Vermelho’, ‘Apoatã’, ‘Obatã’ e ‘Mundo Novo’), mantidas em câmara climatizada a 25º ± 1º C, UR 70 ± 10% e fotofase de 14 horas. Fêmeas de B. phoenicis foram colocadas sobre a superfície das folhas (arenas), por um período de 24 horas, para oviposição. Após este período, as fêmeas e os ovos excedentes foram retirados deixando-se apenas um ovo por arena. As arenas foram examinadas diariamente para se avaliar a sobrevivência e o número de ovos depositados. Preparou-se uma tabela de vida de fertilidade com os dados obtidos. Os ácaros B. phoenicis apresentaram diferenças de sobrevivência e taxas de crescimento populacional, quando criados nos diferentes cultivares de café. Os cultivares mais favoráveis para a multiplicação de B. phoenicis foram, nesta ordem: ‘Apoatã’, ‘Mundo Novo’ e ‘Obatã, baseando-se nas taxas finitas de incremento. ‘Icatu Vermelho’ mostrou-se o cultivar menos favorável à multiplicação de B. phoenicis.

Ecological interactions between phytophagous and predaceous mites in citrus agroecosystems in Taquari Valley, Rio Grande do Sul, Brazil

Abstract We examined the interaction between phytophagous and predaceous mites in Valencia orange (Citrus sinensis) orchards at different altitudes in the Taquari Valley, Rio Grande do Sul, Brazil. Mites were sampled monthly from February 2005 to January 2006 in three citrus agroecosystems: Arvorezinha, Encantado and Taquari. For each agroecosystem, twelve leaves were taken from each of ten citrus plants, plus ten fruits and leaves from five associated plants found in citrus orchards. Predaceous species considered important were Agistemus floridanus Gonzalez (Stigmaeidae), Euseius ho (De Leon) (Phytoseiidae) and Pronematus anconai Baker (Iolinidae). Other predators found were Iphiseiodes zuluagai Denmark & Muma (Phytoseiidae), in Taquari and Homeopronematus sp. (Iolinidae), Parapronematus sp. (Iolinidae), Neoseiulus tunus (DeLeon) (Phytoseiidae) and Typhlodromips cananeiensis Gondim Jr. & Moraes (Phytoseiidae), in Encantado. The most frequent phytophagous mites were Brevipalpus phoenicis (Geijskes) (Tenui...

CITRUS LEPROSIS IN FLORIDA, USA, APPEARS TO HAVE BEEN CAUSED BY THE NUCLEAR TYPE OF CITRUS LEPROSIS VIRUS (CiLV-N)

Citrus leprosis (CL) is a highly destructive viral disease vectored by Brevipalpus phoenicis Geijskes (Acari: Tenuipalpidae). It was first described in Florida in 1907 and last reported in 1968. CL was found after the 1920s in South America (Paraguay, Argentina and Brazil) and presently is known to occur in most of the South American countries. After its detection in Panama in 2000, the disease spread quickly northward through Central America and is now established in Southern Mexico, threatening all of the Caribbean islands as well as the citrus growing areas within the United States. The disappearance of the CL from the United States could be attributed to the severe freeze of December 1966. Multiple spray applications of sulphur for mite control could have gradually reduced the source of inoculum by substantially reducing the Brevipalpus populations. Recent ultrastructural studies revealed that CL may be caused by two distinct viruses, respectively the rare nuclear type (CiLV-N) and the prevalent cytoplasmic type (CiLV-C). A slight difference in foliar lesions caused by these viruses was noticed. CiLV-C produces leaf lesions that become larger in size, with a pale green color and commonly having gummy rings while CiLV-N induces smaller lesions with a dark center and a bright yellow halo. Analysis of available photographic records and samples in the Herbarium of the Instituto Biologico de Sao Paulo in Brazil strongly suggest that CL in Florida was caused by CiLV-N. This helps to explain the disappearance of CL from the United States because it is now known that CiLV-N is less aggressive than CiLV-C. DOI: http://dx.doi.org/10.17525/vrr.v16i1-2.51

False spider mites (Acari: Tenuipalpidae) as pests on orchids (Phalaenopsis hybrids) in Poland

False spider mites (Acari: Tenuipalpidae) as pests on orchids (Phalaenopsis hybrids) in Poland So far, no false spider mites have been reported from orchids in Poland. This paper provides information about Tenuipalpus pacificus Baker, which was recorded for the first time in Poland, on Phalaenopsis hybrids imported from China. Diagnostic characters are also given for Brevipalpus phoenicis (Geijskes), which was up to this time not found on orchids in Poland. It was earlier found on orchids only in Hawaii. The types of injuries caused by false spider mites and results of chemical control of T. pacificus with various acaricides are given. The best results were observed after repeated treatment with Ortus 05 SC (fenpyroximate).

Scanning electron microscopic (SEM) study of selected Tenuipalpidae (Acari: Prostigmata; Pentamerismus, Aegyptobia) from Turkey

Summary False spider mites (Acari: Tenuipalpidae) are flattened and red in color. They are distributed worldwide and considered as cosmopolitan pests. Some of the species are host specific, found on greenhouse plants as well as many other plants. Some of the tenuipalpids, such as Pentamerismus sp., have been found on coniferous host plants and forest trees such as Juniperus sp. and Thuja sp. Tenuipalpids puncture the epidermis of the host plants and suck out the juices with their needle-shaped mouth parts. Their damage causes leaves to turn brown and finally to wilt and die. This damage resembles that caused by spider mites. Although taxonomic characters are extensively used for the identification of tenuipalpids, their ultrastructure is not sufficiently well studied. False spider mite species were surveyed in recreational areas in Ankara, Turkey in 2008 and 2009. Thuja sp., Juniperus sp., and Taxus sp. were sampled and the mite species collected were identified using a light microscope. Their identification is difficult and will be discussed. The taxonomic characters of the identified species are illustrated using scanning electron microscope (SEM) micrographs. Four tenuipalpid species belonging to two genera were identified: Pentamerismus oregonensis McGregor, 1949, Pentamerismus taxi (Haller, 1877), Aegyptobia aletes (Pritchard & Baker, 1958), and Aegyptobia nr. cupressus Baker & Tuttle, 1972. Some of their morphological features and world distributions are presented.

Influência da dureza e potencial hidrogeniônico da calda de pulverização sobre o controle do ácaro-da-leprose em frutos de laranja doce

Muitos são os relatos de ineficiência de agrotóxicos no controle de pragas quando estes são preparados em soluções com água dura e pH elevado. Assim, o trabalho teve como objetivo avaliar o efeito da dureza da água e o pH de soluções acaricidas, em diferentes períodos de tempo após o preparo da calda (0 e 24 horas) no controle do ácaro-da-leprose Brevipalpus phoenicis (Geijskes). O bioensaio foi conduzido sobre frutos de Citrus sinensis (L.) Osbeck cv. Valência. Utilizou-se o delineamento inteiramente ao acaso, com 14 tratamentos e 4 repetições, sendo a parcela experimental composta de um fruto com 10 fêmeas do acarino por fruto. Os acaricidas testados nas dosagens registradas foram: propargite, hexitiazoxi e espirodiclofeno. A pulverização dos frutos foi feita em torre de Potter adaptada, conferindo um volume equivalente a 1616 L ha-1. As avaliações foram realizadas até 49 dias após aplicação dos produtos, contando o número de adultos, ninfas e, na avaliação final, o número de ovos do acarino por fruto. A dureza da água, pH e tempo de preparo não interferiram no controle do ácaro da leprose. Os acaricidas, após mistura com os diferentes tipos de água, não alteraram o pH das soluções, os quais mostraram pequenas variações de pH no decorrer de 24 horas. Todos os acaricidas propiciaram alta eficácia de controle do acarino nas diferentes condições de preparo de calda, mostrando que esses fatores não interferiram no potencial acaricida.