ABSTRACT Aiming to the red mite Oligonychus yothersi control in yerba-mate, the systemic action of an azadirachtin-based product (12 g of azadirachtin.L-1) was evaluated in the laboratory. To assess the activity on oviposition and mortality of the mite (1), three weekly applications of the product in an aqueous solution (30, 48, and 66 mg i.a..L-1) were performed. The applications were carried out in the soil, next to the base of yerba mate seedlings. After seven days of each application, leaves were removed for infestation with 15 adult mite females. To evaluate the activity in the development, survival, and reproduction of the progeny (2), yerba mate seedlings were irrigated with azadirachtin solution of 30 mg i.a..L-1 (recommended concentration). After seven days, leaves were removed and infested with adult females for oviposition and observation of the progeny. Reduction in fecundity (from 23.7 to 44.2%), fertility (27.4 to 48.1%), and an increase in mortality from 14.6 to 47.5% were observed in females fed on azadirachtin-treated plants. Continuous feeding on plants treated with azadirachtin solution significantly reduced oviposition, pre-oviposition period, and longevity of males. In addition, the viability of the egg-adult, and the duration of the egg-adult period increased. The potential of azadirachtin for the control of O. yothersi and its action from the irrigation of yerba mate plants was confirmed.

Abstract Brazil is among the largest apple producers in the world (Malus domestica Bork, Rosaceae), with production concentrated mainly in the southern of the country. Panonychus ulmi (Koch) (Tetranychidae) have economic importance in apple and, recently, Aculus schlechtendali (Nalepa) (Eriophyidae), was reported in Brazil. This review aims to delineate the distribution of the acarofauna associated to apple, with emphasis on the main groups of economic importance and their potential natural enemies and highlight the problems related to phytophagous species and management possibilities. Searches were carried out in databases, and the principal keywords were Aculus schlechtendali, Malus domestica and Panonychus ulmi. After the exclusion criteria resulted 166 publications. The social and economic importance of the apple has been increasing on the world, however, due to environmental imbalance, phytophagous mites are increasing their populations and acquiring resistance against acaricides. Panonychus ulmi has been reported in America for decades, being of economic importance for Brazil and the record of A. schlechtendali alerts to the possibility of damage in orchards in the country. Therefore, it is important that the literature be evaluated, that the mite species are identified and that forms of conscious management are developed. Prioritizing the human and animal health and environmental balance.

ABSTRACT. Phytophagous mites can cause economic losses in many crops, including grapevines. The changes in their population levels may be associated with changes in the predator-prey relationship. Knowledge of the distribution of mites in plants is important for planning sampling strategies and facilitating control decisions. The aims of this study were to (i) evaluate the abundances of Tetranychus urticae (Tetranychidae) and Neoseiulus californicus (Phytoseiidae), and the correlations between them and environmental factors; (ii) determine their distribution on the top, middle, or base strata of the evaluated grapevines (Vitis vinifera, Chardonnay cultivar) and, additionally, report the first occurrence of damage caused by T. urticae in grapevine leaves in the state of Rio Grande do Sul, Southern Brazil. Sixteen samplings were conducted, divided between the 2018 and 2019 seasons. In each sampling, three leaves from the three strata of the plant (top, middle, and base) were collected from 20 plants, totaling 60 leaves per sampling. The predator-prey relationship and their association with environmental variables were evaluated with multivariate correlation, whereas the number of mites per plant leaf strata was compared using a generalized linear mixed model in R software. It was possible to observe the symptoms of damage caused by T. urticae attacks on grapevines in Southern Brazil, characterized by the presence of yellow spots and general yellowing of the vineyard. Our findings indicate that T. urticae and N. californicus individuals are strongly associated with each other regardless of the environmental variables, and such relationship occurs mainly on the lower strata (middle and base leaves) of grapevines. Thus, by taking into account the damage on the leaves of grapevines and the occurrence of T. urticae and N. californicus majorities on specific strata of these vineyards, we suggest that the lower strata of grapevines should be the priority targets for management strategies to control such mites.

Resumo: Muitos estudos relatam que a interação entre as larvas parasitas e seus hospedeiros Odonata afetam o sucesso do acasalamento, o voo e a longevidade. Foram analisados machos e fêmeas de espécies de Odonata coletados nas estepes e planícies costeiras do bioma Pampa do Rio Grande do Sul. Os ácaros foram removidos quando presentes e a prevalência e intensidade dos parasitas foram calculadas. O objetivo deste estudo foi pesquisar e relatar novas espécies hospedeiras de Odonata que estão parasitadas por larvas de ácaros aquáticos, avaliar as taxas de prevalência e intensidade; avaliar a diferença na ocorrência e frequência de ácaros em fêmeas e machos e entre o tórax e abdômen de libélulas e libelulinhas no bioma Pampa meridional localizado no Rio Grande do Sul. Um total de 162 ácaros foram encontrados associados a duas famílias de Odonata: Coenagrionidae (Acanthagrion lancea Selys, 1876, Ischnura capreolus Hagen, 1861 e Ischnura fluviatilis Selys, 1876) e Libelullidae (Micrathyria ocellata Martin, 1897 e Perithemis mooma, 1889) Kirby. Todos os ácaros foram identificados como Arrenurus (Arrenurus) sp. (Arrenuridae) e apresentaram números elevados quando anexados a I. capreolus (55,5%), I. fluviatilis (33,3%), seguido por números baixos em M. ocellata (6,1%), A. lancea (3,7%) e P. mooma (1,2%). Os ácaros foram encontrados em machos e fêmeas de I. capreolus e I. fluviatilis, fêmeas de A. lancea e P. mooma e em M. ocellata apenas em machos. Como as espécies de Odonata parasitadas são generalistas e abundantes em todos os tipos de corpos d’água, acredita-se que características associadas ao acasalamento e oviposição ou comportamento larval explicam a frequência de parasitismo nessas espécies.

Abstract: Many studies have reported that the interaction between water mite larvae and their Odonata hosts affects mating success, flight, and longevity. Males and females of Odonata species collected in the steppes and coastal plains (Pampa Biome) of Rio Grande do Sul were analyzed. Mites were removed when present and the prevalence and intensity of parasites was calculated. The aim of this study was to search and report new Odonata hosts species that are parasitized by water mite larvae and also to evaluate the prevalence and intensity rates; the differences in mite occurrence and frequency between males and females, and between thorax and abdomen of the dragonflies and damselflies in the southern Pampa biome located in Rio Grande do Sul. A total of 162 larval mites were found associated to two Odonata families: Coenagrionidae (Acanthagrion lancea Selys, 1876, Ischnura capreolus Hagen, 1861 and Ischnura fluviatilis Selys, 1876) and Libelullidae (Micrathyria ocellata Martin, 1897 and Perithemis mooma Kirby, 1889). All mites were identified as Arrenurus (Arrenurus) sp. (Arrenuridae) and showed high numbers when attached to I. capreolus (55.5%), I. fluviatilis (33.3%), followed by low numbers on M. ocellata (6.1%), A. lancea (3.7%), and P. mooma (1.2%). Mites were found on males and females of I. capreolus and I. fluviatilis, females of A. lancea and P. mooma and in M. ocellata only in males. As the parasitized Odonata species are generalist and abundant in all water body types, traits associated with mating and oviposition or larval behavior are believed to explain the frequency of parasitism in these species.

Resumo A resistência de algumas espécies de Anopheles a inseticidas químicos está se espalhando rapidamente por todo o mundo e tem dificultado as ações de prevenção e controle da malária. O principal mecanismo responsável pela resistência nestes insetos parece ser o sítio-alvo conhecido como resistência knock-down resistance (kdr), que causa mutações no canal de sódio. Mesmo assim, muitos países fizeram progressos significativos na prevenção da malária, concentrando-se em grande parte no controle do vetor através redes inseticidas de longa duração (RILD), e de pulverização residual interna (PRI) de inseticidas. O objetivo desta revisão é contribuir com informações sobre os inseticidas mais aplicados para o controle dos principais vetores da malária, seus efeitos, e os diferentes mecanismos de resistências. Atualmente é necessário olhar para outras alternativas, como por exemplo, controle biológico e produtos derivados de plantas e fungos, pela utilização de outros organismos como um possível regulador de populações de vetores da malária em surtos críticos.

Abstract The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs), indoor residual spraying and (IRS) of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks.

Resumo A resistência de algumas espécies de Anopheles a inseticidas químicos está se espalhando rapidamente por todo o mundo e tem dificultado as ações de prevenção e controle da malária. O principal mecanismo responsável pela resistência nestes insetos parece ser o sítio-alvo conhecido como resistência knock-down resistance (kdr), que causa mutações no canal de sódio. Mesmo assim, muitos países fizeram progressos significativos na prevenção da malária, concentrando-se em grande parte no controle do vetor através redes inseticidas de longa duração (RILD), e de pulverização residual interna (PRI) de inseticidas. O objetivo desta revisão é contribuir com informações sobre os inseticidas mais aplicados para o controle dos principais vetores da malária, seus efeitos, e os diferentes mecanismos de resistências. Atualmente é necessário olhar para outras alternativas, como por exemplo, controle biológico e produtos derivados de plantas e fungos, pela utilização de outros organismos como um possível regulador de populações de vetores da malária em surtos críticos.

Abstract The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr), which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs), indoor residual spraying and (IRS) of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks.

Background Strawberry is a pseudofruit mainly cultivated in temperate climate regions. Considering its high levels of ascorbic acid and phenolic compounds, the consumption of strawberry fruit can be beneficial to health. The Brazilian strawberry production revolves around 3000 tons per year, significantly influencing the food market and generating income to farmers. However, this production can be partially impaired by two-spotted spider mite (TSSM) Tetranychus urticae Koch infestations, due to decreases in the quality and quantity of fruit. Since there are no data in the literature about alterations caused by TSSM infestation in strawberry plants, our work aimed towards evaluating nutritional and physicochemical parameters of TSSM-infested strawberry plants, along with the related chemical treatment (CT) (acaricide) or biological treatment (predatory mite Phytoseiulus macropilis Banks). Results Strawberry fruit from TSSM-infested plants present the highest levels of acidity and exhibit low levels of anthocyanin and phenolic compounds, while fruit from TSSM-infested plants + biological control using predatory mite shows high levels of soluble solids, phenolic compounds and ascorbic acid, along with a high soluble solid content/titratable (SSC/TA) acidity ratio, which indicates high quality fruit. Conclusions Our results suggest that TSSM infestation decreases fruit quality and that the biological control of TSSM using a predatory mite is a suitable alternative to organic production, since the presence of predatory mite does not affect fruit quality and development.

Neoseiulus HUGHES, 1948 is currently one of the largest genus of Phytoseiidae Berlese. Neoseiulus demitei sp. nov., a new species of phytoseiid mite from Rio Grande do Sul State, Brazil, is illustrated and described based on specimens collected on Tibouchina sp. (Melastomataceae) plants. This new species differs from others by having most of propodossomal setae reaching the base of nearby setae and a constriction of ventrianal shield at level of preanal pores. Nevertheless, this new species is the first of the species subgroup kennetti described from Brazil. A key of Neoseiulus species reported in Brazil is also included.

Apesar da grande importância da cultura do pêssego [Prunus persica (L.) Batsch] no Rio Grande do Sul, pouco se conhece sobre a diversidade e a flutuação populacional de ácaros considerados importantes para esta cultura. O objetivo deste trabalho foi conhecer a flutuação populacional das espécies acarinas associadas às cultivares Premier e Eldorado nos municípios de Roca Sales e Venâncio Aires, Rio Grande do Sul. O estudo foi realizado no período de julho de 2008 a junho de 2009, quando foram amostradas 15 plantas escolhidas ao acaso numa área em cada município. As plantas foram divididas em quadrantes, e de cada quadrante foi escolhido um galho de onde foram retiradas três folhas das regiões apical, mediana e basal, totalizando 180 folhas/área. Foram coletadas, mensalmente, parte de cinco plantas não cultivadas mais abundantes. O período de uma hora sob microscópio estereoscópio foi suficiente para se obter uma amostra representativa. Um total de 1.124 ácaros foi coletado pertencentes a 14 famílias e 28 espécies. Tetranychus ludeni Zacher, 1913, Panonychus ulmi (Koch, 1836) e Mononychellus planki (McGregor, 1950) foram os ácaros fitófagos mais abundantes, enquanto Typhlodromalus aripo Deleon, 1967 e Phytoseiulus macropilis (Banks, 1904) os ácaros predadores mais comuns. O esforço amostral foi suficiente. Nos dois pomares avaliados, os índices ecológicos foram baixos, mas um pouco superiores em Premier (H' 0,56; EqJ: 0,43) quando comparados a Eldorado (H' 0,53; EqJ 0,40). Em Premier não foram observadas espécies constantes, apenas acessórias com Brevipalpus phoenicis (Geijskes, 1939), T. ludeni e T. aripo. Maior abundância foi observada em dezembro e janeiro, e maior quantidade em abril. Em Eldorado, T. ludeni e P. ulmi foram constantes. Maior abundância foi observada em novembro e dezembro, e maior quantidade em dezembro e janeiro. Não foram observados ácaros nas gemas. Tetranychus ludeni é o ácaro fitófago mais comum, com picos populacionais em novembro, dezembro e janeiro. Alta diversidade de ácaros predadores foi observada tanto em plantas associadas como em plantas de pessegueiro, indicando mobilidade das espécies predadoras na cultura.

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.

Ácaros das famílias Eriophyidae, Tarsonemidae e Tetranychidae são citados como de importância econômica na cultura de amora-preta (Rubus fruticosus, Rosaceae), framboesa e outras frutas pequenas. Este estudo foi conduzido de novembro de 2001 a outubro de 2003 nas cultivares Brazos, Caigangue e Tupy no município de Ilópolis, Rio Grande do Sul, com o objetivo de conhecer a acarofauna e sua dinâmica populacional em amora-preta. Foram coletados 36.094 ácaros pertencentes a 11 famílias. A maioria dos ácaros coletados pertence às famílias Diptilomiopidae (80,9%) e Tetranychidae (13,9%), compostas por espécies fitófagas. Chakrabartiella sp. (Diptilomiopidae), foi a espécie mais abundante, seguida por Neotetranychus asper Feres & Flechtmann, 2000 (Tetranychidae). Stigmaeidae (2,1%) e Phytoseiidae (0,4%) foram os ácaros predadores mais comuns, sendo Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 (Stigmaeidae) e Typhlodromalus aripo DeLeon, 1967 (Phytoseiidae), as espécies de predadores mais abundantes.

Mites of the families Eriophyidae, Tarsonemidae and Tetranychidae are considered of economic importance in the blackberry (Rubus fruticosus, Rosaceae), raspberry and other small fruit crops. This study was conducted from November of 2001 to October of 2003 on Brazos, Caigangue and Tupy cultivars in Ilópolis municipality, state of Rio Grande do Sul, to describe the mitefauna and its population fluctuation in blackberry crops. A total of 36,094 mites belonging to 12 families was collected. Most of the mites belong to Diptilomiopidae (80.9%) and Tetranychidae (13.9%), composed predominantly of phytophagous species. Chakrabartiella sp. (Diptilomiopidae) was the most abundant species, followed by Neotetranychus asper Feres & Flechtmann, 2000 (Tetranychidae). Stigmaeidae (2.1%) and Phytoseiidae (0.4%) were the most common families of predaceous mites, and Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 (Stigmaeidae) and Typhlodromalus aripo DeLeon, 1967 (Phytoseiidae) the most common predaceous species.

We tested the functional response of the phytoseiid predator Phytoseiulus macropilis (Banks, 1904) to different population densities of Tetranychus urticae Koch, 1836 (the two-spotted spider mite - TSSM) in the laboratory. We evaluated the curve that best fits the data obtained, based on the reduced X². The predators were obtained from leaves of Oso Grande strawberries at the municipality of Bom Princípio, state of Rio Grande do Sul, Brazil. Fifteen seemingly healthy females of P. macropilis were randomly chosen and individualized in each of the arenas with different TSSM densities. The following prey densities were tested: 1, 2, 3, 5, 10, 20, 30, 35, 45, 55, 70 and 125 females. The tests were performed in a germination chamber with photoperiod of 12 hours at 28 ± 1ºC per day and 22 ± 1ºC at night and 80 ± 5% relative humidity. In all tests with up to three prey items, P. macropilis showed low functional response, whereas higher rates were observed when more prey items were offered. There was a strong positive correlation between increased prey numbers and daily prey consumption (r = 0.84 and p = 0.0006). A significant correlation was found between prey consumption and total oviposition (r = 0.70, p = 0.01). The daily oviposition rate was lower when few prey items were offered, increasing significantly with increased prey availability. The results showed a positive correlation between the number of prey items offered to the predator and its oviposition rate (r = 0.66, p = 0.01). Nevertheless, a strong correlation was observed between the daily consumption of prey and eggs/female/day (r = 0.92, p < 0.0001). A shorter oviposition period was reported when up to three prey items were offered. The oviposition period and the increase in prey numbers were positively correlated (r = 0.30, p = 0.34), but the difference was not statistically significant. Nevertheless, the longer the egg-laying period, the greater the oviposition rate (r = 0.90, p < 0.0001). The curve that best fits the data obtained in each case was also calculated, based on the least square method.

Uma nova espécie de Amblyseius Berlese é descrita para o estado do Rio Grande do Sul, no Sul do Brasil. Amblyseius vitis sp. nov. é descrita de Dois Lajeados, Rio Grande do Sul. Os espécimes foram coletados sobre Stachys arvensis L.(Lamiaceae) e Plantago tomentosa Lam. (Plantaginaceae).

A new species of Amblyseius Berlese, A. vitis sp. nov. is described from Dois Lajeados, State of Rio Grande do Sul. The specimens were collected on Stachys arvensis L. (Lamiaceae) and Plantago tomentosa Lam. (Plantaginaceae).

Neste artigo é descrita ocorrência e o dano causado pelo ácaro vermelho europeu Panonychus ulmi (Koch) associado à cultura da videira. As coletas foram realizadas na safra 2005-2006 em Vitis vinifera L. da cultivar Merlot, nos municípios de Bento Gonçalves e Candiota, no Estado do Rio Grande do Sul, Brasil. As folhas infestadas apresentaram bronzeamento, com manchas avermelhadas na face adaxial, resultando na queda prematura das mesmas. Esse é o primeiro registro do ácaro vermelho europeu danificando a cultura da videira no Rio Grande do Sul.

The occurrence and the damage caused for the European red spider mite Panonychus ulmi (Koch) associated to the culture of the grapevine are described. The collections had been carried through in 2005-2006 seasons in Vitis vinifera L. of cultivating Merlot in Bento Gonçalves and Candiota counties, in the state of Rio Grande do Sul, Brazil. The infested leaves had presented bronzing, with spots redly in the adaxial face resulting in the premature fall. This is the first register of the European red mite damaging the culture of the grapevine in Rio Grande do Sul.

Apesar da grande importância da cultura da seringueira (Hevea brasiliensis Muell. Arg.) para o Brasil, pouco se conhece sobre a flutuação populacional dos ácaros nessa cultura. O objetivo deste trabalho foi estudar a flutuação populacional de ácaros na seringueira no Estado do Mato Grosso, bem como observar a evolução dos sintomas de ataque de tais pragas nessa planta. O estudo foi conduzido em campos de seringueira de Itiquira e Pontes e Lacerda, Estado do Mato Grosso, com seis clones: FX 3864, RRIM 600, IAN 873, IAN 713, PB 260 e PR 255, cujas coletas foram realizadas de agosto de 1998 a julho de 2000. Na safra de 1998/1999, a amostragem foi de 150 folhas de cada um dos estratos basal, mediano e apical, em 10 plantas ao acaso. A metodologia de coleta na safra de 1999/2000 foi alterada devido aos resultados da parcial anterior de cinco folhas do estrato mediano de cada uma das 15 plantas ao acaso. Calacarus heveae Feres foi a espécie mais freqüente em Itiquira e Phyllocoptruta serigueirae Feres em Pontes e Lacerda. A queda prematura das folhas foi observada apenas em Itiquira.

Despite the importance of rubber trees (Hevea brasiliensis Muell. Arg.) to Brazil, little is known about mite population fluctuation on this crop. The aim of this work was to study the fluctuation of the mite population on rubber trees in the state of Mato Grosso and to observe the evolution of the symptoms caused by their attack. This study was conducted in rubber tree fields at Itiquira and Pontes e Lacerda in the state of Mato Grosso with six clones: FX 3864, RRIM 600, IAN 873, IAN 713, PB 260 and PR 255. Samplings were conducted between August 1998 and July 2000. The 1998/1999 samples consisted of 150 leaves of each of the basal, median and apical strata of 10 plants, randomly taken. The 1999/2000 sampling methodology was changed due the results for the previous partial for five leaves of the median stratum of each of 15 plants randomly taken. Calacarus heveae Feres was the most frequent species in Itiquira and Phyllocoptruta serigueirae Feres in Pontes e Lacerda. Early leaf drop was observed only in Itiquira

Calacarus heveae Feres, 1992 é um eriofídeo descrito de espécimes coletados em plantas de seringueira (Hevea brasiliensis, Euphorbiaceae) na região noroeste do Estado de São Paulo. Esse ácaro prefere a face adaxial dos folíolos e pode causar a perda do brilho, amarelecimento, bronzeamento dessa região e a subseqüente queda prematura das folhas. O objetivo deste trabalho foi analisar a distribuição de C. heveae em seringueira, selecionar a unidade de amostragem mais representativa e desenvolver um plano de amostragem para o estudo de sua flutuação populacional. O trabalho foi conduzido com os clones PB 260 e IAN 873, respectivamente nos municípios de Itiquira e de Pontes e Lacerda, ambos no Mato Grosso. Em Itiquira, diferenças significativas foram observadas em quatro ocasiões em relação ao número médio de ácaros por folha nos diferentes estratos das plantas. Nas amostragens realizadas em Pontes e Lacerda, nenhuma diferença significativa foi encontrada entre os estratos em relação àquele parâmetro. Apenas em Itiquira, em uma ocasião de amostragem, foi verificada diferença entre os três estratos, em relação à proporção de folhas infestadas. Nenhuma diferença significativa foi verificada em relação ao número médio de ácaros por folha e proporção de folhas infestadas por C. heveae a diferentes distâncias da periferia da copa. Calacarus heveae exibe distribuição agregada no campo. Para estimar a densidade de C. heveae, um plano numérico e um plano binomial de amostragem foram desenvolvidos.

Calacarus heveae Feres, 1992 (Eriophyidae) is a mite described from specimens collected on rubber tree (Hevea brasiliensis, Euphorbiaceae) in the northwest region of the state of São Paulo. This mite prefers the adaxial face of the folioles which it can turn dry, yellowish and brownish; it can also cause leaf fall. The aim of this work was to analyze the distribution of C. heveae on rubber trees, to select the most representative sampling unit and to develop a sampling plan to determine the populational fluctuation. This study was conducted with clones PB 260 and IAN 873, in Itiquira and Pontes e Lacerda, respectively, both in the state of Mato Grosso. In Itiquira, significant differences were observed in four occasions in relation to the average number of mites per leaf in the different plant strata. In the samplings carried out in Pontes e Lacerda, no significant differences were observed between strata in relation to that parameter. Only in Itiquira, in one occasion, a significant difference between strata was verified in relation to the proportion of infested leaves. No significant differences were verified in relation to the average number of mites per leaf and proportion of leaves infested by C. heveae at different depths in the canopy. Calacarus heveae exhibits aggregated distribution in the field. To estimate the density of C. heveae, numeric and sampling plans were developed.