Liogenys Guérin-Méneville, 1831 (Coleoptera: Scarabaeidae: Melolonthinae: Diplotaxini) from the Chacoan Province and its boundaries: taxonomic overview with four new species.

A taxonomic revision of the Liogenys Guérin-Méneville, 1831 (Coleoptera: Scarabaeidae: Melolonthinae: Diplotaxini) from the Chacoan Biogeographical Province is presented. Liogenys now includes 92 species, including four new species described here: L. neoforcipata Cherman, new species; L. foveata Cherman, new species; L. isotarsis Cherman, new species; and L. truncata Cherman, new species; and the female of L. tarsalis Moser is described for the first time. Six new synonymies are proposed: L. denticulata Moser, 1918 is a new synonym of L. denticeps Blanchard, 1851; L. ophtalmica Frey, 1973 is a new synonym of L. bidenticeps Moser, 1919; L. mendozana incisa Frey, 1969 is a new synonym of L. mendozana Moser, 1918; L. flavicollis Blanchard, 1851 and L. fulvescens Blanchard, 1851 are new synonyms of L. pallens Blanchard, 1851; and L. densicollis Moser, 1921 is a new synonym of L. opacicollis Fairmaire, 1892. Liogenys cribricollis Moser, 1921 species status is revalidated from its synonymy with L. densicollis. A neotype is designated for Liogenys mendozana incisa Frey, 1969, as well as lectotypes for: L. bruchi Moser, 1924; L. cribricollis, L. denticulata, L. denticeps, L. fulvescens, L. latitarsis Moser, 1918; L. mendozana Moser, 1918; L. obscura Blanchard, 1851; L. opacicollis; and L. pallens. Redescriptions and/or diagnoses and updated geographical distributions are provided for 16 species. Six species previously known only from Argentina have their distribution expanded to Bolivia (L. mendozana; L. opacicollis; L. rectangula Frey, 1969), Paraguay (L. nigrofusca Moser, 1918; L. pallens), or to both of these countries (L. latitarsis).

First record of Cnemidochroma phyllopus (Coleoptera: Cerambycidae) in the province of Corrientes, Argentina and potential distribution in the southern part of South America.

Cnemidochroma Schmidt, 1924, a small genus of the tribe Callichromatini endemic in South America, comprises six species of which the only one recorded in Paraguay, Uruguay, Argentina and Brazil is C. phyllopus (Gurin-Mneville, 1844). The aim of this study was to estimate potential suitable areas for C. phyllopus to provide further knowledge on its current distribution. A dataset of 43 records was compiled and species distribution modelling was employed linking these occurrences with bioclimatic variables. Results indicate higher suitability conditions along the Atlantic coast of Brazil, reaching north Uruguay and extending inland to Paraguay and northern parts of Argentina. In addition, we report a new distributional record from Corrientes, Argentina.

Ovomanonychus, a new genus of South American Sericoidini (Coleoptera: Scarabaeidae: Melolonthinae).

Ovomanonychus new genus (Coleoptera: Scarabaeidae: Melolonthinae: Sericoidini) is described based on Ovomanonychus rosettae (Frey, 1976), new combination (type species), Ovomanonychus inajae new species, and Ovomanonychus striatus new species. The genus occurs in Bahia, Mato Grosso, Espírito Santo, Minas Gerais, Paraná, Rio de Janeiro, and São Paulo States, Brazil. Description is provided for the new genus and for its placement in Sericoidini. A key to species is presented along with illustrations, distributional data, and a map for each species.

Population analysis of white grubs (Coleoptera: Melolonthidae) throughout the Brazilian Pampa biome

ABSTRACT The replacement of natural grassland by cultivated areas might favor the increase in abundance of some root-feeding species such as the white grubs, which may become a constraint for field crop production. This research aimed to assay the population density and geographical distribution of white grubs pest and other species in natural grassland and cultivated areas throughout the Brazilian Pampa biome. White grubs were sampled in 18 locations in both landscape use types and identified. Population density (number of larvae m-2) was calculated for each recorded species and sorted within two groups (pest species and other species), compared between natural grasslands and cultivated areas, as well as among locations. A dendrogram to evaluate species similarity among locations was built based on combined data obtained from both landscape use types throughout the region. In total, 31 species were found in the Brazilian Pampa, and four of them are considered as crop pests: Diloboderus abderus (Sturm, 1826), Euetheola humilis (Burmeister, 1847), Lyogenys fusca (Blanchard, 1830), and Phyllophaga triticophaga Morón & Salvadori, 1998. The average population density of pest species in cultivated areas was less than five larvae m-2, at most of locations. Some species had a wide geographical distribution (e.g. D. abderus and Cyclocephala modesta Burmeister), while other melolontids occurred at only one location. The knowledge of which white grub species are present in a field and its population densities assist farmers to take proper management decisions.

A taxonomic revision of Liogenys occurring in Brazil with an interactive key and remarks on New World Diplotaxini (Coleoptera, Melolonthidae).

Liogenys Guérin-Méneville, 1831 is the major genus of Neotropical Diplotaxini, with 78 species distributed from Panama to southern Argentina and Chile, except for Ecuador. Due to the large numbers of both described and undescribed species, as well as its agricultural importance, mainly of those in Brazil, Liogenys was redefined and redescribed. Nine new species are described: L. cavifrons Cherman, sp. n., L. femella Cherman, sp. n., L. piauiensis Cherman, sp. n., L. rotundicollis Cherman, sp. n., L. pseudosanctaecrucis Cherman, sp. n., L. grossii Cherman, sp. n., L. pseudospiniventris Cherman, sp. n., L. sulcoventris Cherman, sp. n., and L. freyi Cherman, sp. n. All the new species are Brazilian, except for the last one, which is Argentinian. Twenty-three Brazilian species are redescribed and illustrated. Five new synonyms are proposed, and 19 lectotypes are designated. New geographical distribution records for 19 species are presented, as well as a key to New World Diplotaxini and Brazilian species of Liogenys.

White grubs (Cyclocephala flavipennis) damaging perennial winter pastures in the South Region of Brazil / Ocorrência do coró-pequeno (Cyclocephala flavipennis) danificando pastagens perenes de inverno na região Sul do Brasil

ABSTRACT: Cyclocephala flavipennis Arrow, 1914 (Coleoptera: Melolonthidae), popularly known as white grub, is an insect widely disseminated in the South Region of Brazil. Despite the frequent occurrence of this white grub in areas cultivated with winter cereals, it is generally not considered a pest, since it feeds on straw and dead plant material. However, in 2015 and 2016, this insect has been identified as the damage-causing agent in the perennial winter pastures in Lages, Santa Catarina, Brazil. Damage was observed in patches and caused reduction in root depth and mass, resulting in loss of vigor, accelerated senescence in aerial parts, and death of tillers in Festuca arundinacea Schreb. and Dactylis glomerata L. plants.

RESUMO: Cyclocephala flavipennis Arrow, 1914 (Coleoptera: Melolonthidae), conhecido popularmente como coró-pequeno, é um inseto amplamente disseminado na região sul do Brasil. Embora seja encontrado com frequência em áreas cultivadas com cereais de inverno não é considerado inseto praga, por alimentar-se preferencialmente de palha e restos de plantas. Entretanto, nos anos de 2015 e 2016 foi identificado como causador de danos em pastagens perenes de inverno em Lages, Santa Catarina, Brasil. Os danos foram observados em reboleiras e promoveram redução na massa e profundidade de raízes, resultando em perda de vigor, senescência acelerada da parte aérea e morte de perfilhos de plantas de Festuca arundinacea Schreb. e Dacytilis glomerata L.

Análise populacional de corós-praga e de outras espécies no planalto do Rio Grande do Sul / Populational analysis of white grub pest and other species in planalto of Rio Grande do Sul, Brazil

O objetivo deste trabalho foi determinar a relação entre a densidade populacional de espécies de corós (Coleoptera: Melolonthidae) reconhecidas como pragas e as outras espécies da mesma família que ocorrem em áreas cultivadas e não cultivadas no planalto, ao norte do Rio Grande do Sul. Foram realizadas amostragens em 23 municípios no período de julho a setembro, nos anos 2009 e 2010, em uma área cultivada e outra sem cultivo. Em cada área, foram abertas trincheiras de 50x25x30cm de profundidade. As larvas coletadas foram identificadas e reunidas em dois grupos: corós-praga e corós de outras espécies. Comparou-se a densidade populacional (no de larvas m-2) entre os dois grupos nas áreas cultivadas e não cultivadas. A densidade de outras espécies foi superior à densidade de espécies-praga, tanto nas áreas cultivadas (9,0 e 3,9 larvas m-2, respectivamente) quanto nas áreas não cultivadas (6,6 e 3,9 larvas m-2, respectivamente). Não há diferença na densidade populacional média de corós-praga entre áreas cultivadas e não cultivadas.

This study aimed to determine the relationship between the population density of pest and other species of white grubs (Coleoptera: Melolonthidae) occurring in cultivated and uncultivated fields in the planalto region, in northern Rio Grande do Sul. Sampling was carried through 23 municipalities, from July to September 2009 and 2010 in two areas, one cultivated and another noncultivated, In each area, trenches of 50x25x30cm were opened. Melolontid larvae collected were identified and gathered in two groups: "pest-species" and "other species". Populational density (no of larvae m-2) of the two groups were compared between cultivated and noncultivated areas. The "other species" density was higher than pest community in both cultivated (9,0 e 3,9 larvae m-2) and noncultivated areas (6,6 e 3,9 larvae m-2 respectively). There is no difference between means of pest species population density between cultivated and noncultivated areas.

Uso da geoestatística para caracterização da distribuição espacial de larvas de Diloboderus abderus / Geostatistical use for characterization of the spatial distribution of larvae of Diloboderus abderus

No Brasil, existem registradas aproximadamente mil espécies de corós, destacando-se, dentre os de maior importância, Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae), pelos prejuízos que pode causar aos cultivos agrícolas e a ampla ocorrência geográfica. O trabalho teve por objetivo caracterizar, com uso da geoestatística, a distribuição espacial de larvas de D. abderus. O estudo foi realizado no ano de 2009, em lavouras de aveia nos municípios de São Francisco de Assis, Cruz Alta e Lagoa Vermelha, RS. Os perímetros das áreas foram demarcados com receptor de sistema de posicionamento global, e os grides de amostragem tiveram dimensão de 70x70m. A densidade populacional foi estimada com abertura de uma trincheira em cada ponto amostral. As análises da variabilidade espacial e da dependência espacial foram feitas por meio de semivariogramas e classificadas segundo CAMBARDELLA et al. (1994). Já os mapas foram gerados a partir dos dados de contagem de larvas em campo. Os semivariogramas indicam a presença de dependência espacial nas áreas de avaliação. Os grides de amostragem mostraram-se apropriados para caracterizar a distribuição espacial de larvas de D. abderus. A distribuição espacial de D. abderus é agregada e seu conhecimento pode melhorar o manejo da praga.

In Brazil, there are about a thousand recorded species of white grubs, and among them the most important is Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae), because of the damage caused to agricultural crops and the wide geographic occurrence. The study aimed to characterize, using geostatistical, the spatial distribution of larvae of D. abderus. The study was conducted during 2009 in oat crops in the counties of São Francisco de Assis, Cruz Alta and Lagoa Vermelha, RS. The perimeters of the fields were delimited with global positioning system receptor, and the sampling grids dimensions were 70x70m. The population density was estimated by opening a trench in each sampling point. The analysis of spatial variability and spatial dependence were made by semivariograms and classified from CAMBARDELLA et al. (1994). Maps were generated from the counting data of larvae in the field. The semivariograms indicate the presence of spatial dependence in the assessment areas. The sampling grids proved to be suitable to characterize the spatial distribution of D. abderus larvae. The spatial distribution of D. abderus is aggregated and this knowledge may improve pest management.

Dimensionamento de amostra na estimação da população de corós em áreas de campo nativo e de cultivo no Estado do Rio Grande do Sul / Sample size for estimating population density of white grubs in native and cultivated areas in Rio Grande do Sul State, Brazil

É importante quantificar a densidade populacional de corós para definir o momento adequado para o controle da praga. Assim, o objetivo deste trabalho foi determinar o tamanho de amostra (número de trincheiras por hectare) para a estimação da média de densidade populacional de corós em áreas de campo nativo e de cultivo em diferentes locais do Estado do Rio Grande do Sul. Foram coletados dados de densidade populacional de corós, independentemente de espécie, em áreas de campo nativo e de cultivo em 17 locais, por meio de contagens realizadas em trincheiras de 20cm x 50cm com 30cm de profundidade. Em cada uma das 34 áreas amostradas, calcularam-se medidas de tendência central, de variabilidade, de assimetria e de curtose, e testou-se a normalidade dos dados. Em seguida, verificou-se a homogeneidade de variâncias entre as áreas em cada local e entre os locais em cada área. Depois, calculou-se o tamanho de amostra em cada área e local. O tamanho de amostra (número de trincheiras por hectare) para a estimação da média de densidade populacional de corós é dependente da área (campo nativo ou de cultivo) e do local. Para as áreas e os locais estudados, 61 trincheiras por hectare são suficientes para estimar a média de densidade populacional de corós, para um erro de estimação igual a 30 por cento da média estimada, com grau de confiança de 95 por cento.

It is important to quantify the population density of white grub to set the appropriate time to control the pest. The aim of this study was to determine the sample size (number of trenches per hectare) to estimate the average population density of white grubs in native and cultivated areas in different locations of Rio Grande do Sul State, Brazil. Data were collected from white grubs' population density in native and cultivated areas of 17 locations, regardless of species, through counts in trenches 20cm x 50cm dug to a depth of 30cm. In each of the 34 areas sampled, the central tendency, variability, asymmetry and kurtosis was calculated and the normality data were tested. Then it was verified the homogeneity of variance among areas in each locality and among locations in each area and it was determined the sample size to estimate the average population density of white grubs in each area and locality. The sample size (number of trenches per hectare) to estimate the average population density of white grubs is dependent on the area (native or cultivated) and locality. It was concluded that 61 trenches per hectare are enough to predict the average population density of white grubs, with an estimation error equal to 30 percent of estimated average, with a degree confidence of 95 percent.