Diloboderus Abderus Research Articles

Evaluation of different insecticides and application methods for control of Diloboderus abderus

Diloboderus abderus (Coleoptera: Melolonthidae), commonly known as "isoca", is an insect that lives in the natural field, fulfilling the function of recycling nutrients. It is an important soil pest for crops such as corn, wheat, oats and natural and cultivated grasses in countries such as Argentina, Paraguay, Uruguay and southern Brazil. In the last five years, Montes del Plata has recorded significant losses in young plantations associated with soils with a history of farms, mainly in the southwest region of the country. This damage is associated with the larval phase of the isoca, which develops in the A horizon of the soil, feeding on the roots of the recently planted eucalyptus seedlings, which can cause the death of the tree. For this reason, the objective of this work was to evaluate the control effectiveness of three active ingredients (Imidacloprid, Acetamiprid and Thiamethoxan), and the best application method (foliar, surface application to the soil and root immersion) that would allow protecting the plants in their critical stage. The evaluation was carried out on Eucalyptus plants in pots where three stage-three isocas larvae were placed. After 30 days, the plants were dug up and plant survival, root damage, and larval mortality were evaluated. The results indicated that the three active ingredients were efficient in control, with survival rates of isoca of less than 30%. Thiamethoxan was the most efficient with 100% control of isocas, regardless of the application method. The foliar application method showed the best results with isocas survival rates of less than 15%, regardless of the active ingredient applied. Although it is necessary to continue the research by evaluating different site conditions, application times and doses of active ingredients, the results achieved indicate that the application of Thiamethoxan on the plantation line is the profitable alternative to mitigate losses.

Determination of damage caused by different populations of Diloboderus abderus (Coleoptera: Scarabaeidae) larvae on wheat

Fil: del Valle, Eleodoro Eduardo. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe; Argentina

Phylogeography Approach of Diloboderus abderus (Coleoptera: Melolonthidae) in the Southern Cone of America.

Diloboderus abderus (Sturm, 1826) (Coleoptera: Melolonthidae) is a serious soil pest of corn, wheat, oat, and natural and cultivated pastures in Argentina, Paraguay, Uruguay, and southern Brazil. Despite its economic importance, the genetic diversity and population structure of D. abderus remain unknown. We sequenced a fragment of the mitochondrial gene cytochrome oxidase I region (COI), of six populations of D. abderus from the Southern Cone of America. The mtDNA marker revealed a high haplotype diversity, high pairwise FST values, and significant genetic variations among populations. No correlation was found between genetic and geographical distances, yet the most common haplotype (Dab01) was present in four out of the six populations. Analysis of molecular variance showed that most of the variation was within populations of D. abderus. Tajima's D and Fu's FS tests indicated no evidence that D. abderus populations are under recent expansion. Our results indicate that genetic-based traits will likely remain localized or spread slowly, and management strategies need to be undertaken on a small scale.

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

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 larvaem−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.

Abundance and Diversity in the Melolonthidae Community in Cultivated and Natural Grassland Areas of the Brazilian Pampa.

Annual crops or exotic trees for cellulose extraction have replaced natural grassland areas of the Brazilian Pampa biome. These activities have been intensified in recent years and may lead to changes in the white grub complex. The objective of this study was to characterize the diversity and abundance of white grubs in cultivated and natural grassland areas of the Brazilian Pampa biome. We conducted samplings in natural grassland and cultivated areas throughout 18 locations in the Brazilian Pampa. Diversity index and nonmetric multidimensional scaling (NMDS) were used to compare the Melolonthidae community within and between cultivated and natural grassland areas. Diloboderus abderus Sturm, Cyclocephala modesta Burmeister, and Plectris sp.5 (Coleoptera: Melolonthidae) were the most abundant taxa, accounting for 49.08% of all white grubs collected from both land use types. Abundance, diversity, and evenness indices were greater in natural grassland than in cultivated areas. The NMDS demonstrated that natural grassland and cultivated areas share similar white grub species assemblages, with 22 species collected in both land use types. Our data suggest that most of the Melolonthidae species collected in the Brazilian Pampa are capable of persisting in cultivated areas. This is the first work characterizing the Melolonthidae community throughout the Brazilian Pampa, which is vital for implementing pest management tactics and conservation of beneficial species.

Biological control of Diloboderus abderus (Coleoptera: Scarabaeidae) larvae using Steinernema rarum CUL (Nematoda: Steinernematidae) and Heterorhabditis bacteriophora SMC (Nematoda: Heterorhabditidae)

The advance of no-till management systems in agriculture favored the increase of Diloboderus abderus (Sturm) populations in most of the cultivated areas in South America. Damage to wheat crops (Triticum aestivum Linnaeus) is caused by the larvae, commonly known as white grubs, which consume seeds and roots, weakening or killing the plants. Entomopathogenic nematodes (EPNs) are insect parasites usually used as biological control agents of larvae of Scarabaeidae species. However, a great variability in pathogenicity and virulence against different white grubs has been observed among EPN species and isolates of a single species. The aim of this work was to evaluate the pathogenicity of Steinernema rarum (de Doucet) CUL isolate, Heterorhabditis bacteriophora (Poinar) SMC isolate and their symbiotic bacteria against D. abderus larvae. Wheat plants were grown in plastic pots under greenhouse conditions and one larva (L1, L2 or L3) of D. abderus was placed in each pot and then inoculated with 1000 EPN IJs. H. bacteriophora caused 95 and 45% mortality to L1 and L2, respectively. No L3 mortality caused by the studied isolates was observed. Field experiments were conducted in wheat plots in 2013 and 2014. Treatments consisted of surface application of S. rarum or H. bacteriophora (2.5 × 109 IJs/ha) and chlorpyrifos; control treatments contained only distilled water. Evaluations were made at day 0, 30 and 60 after treatments by randomly selecting eight sites from each plot and determining the number of D. abderus L2. Larval populations were reduced in plots treated with H. bacteriophora and chlorpyrifos. Larval populations were reduced in plots treated with H. bacteriophora and chlorpyrifos. The plots treated with S. rarum did not show differences in the insect population with respect to the control. EPN symbiotic bacteria were injected into the hemocoel of each larval stage to determine virulence against D. abderus. D. abderus larval mortality caused by symbiotic bacteria was significantly influenced by bacterial concentration and larval stage. H. bacteriophora showed a greater reproductive capacity than S. rarum. We conclude that H. bacteriophora SMC have potential for use as biological control agents of D. abderus first and second-instar larvae.

Fusarium oxysporum dispersion by larvae of Cyclocephala modesta, Dyscinetus gagates and Diloboderus abderus in Brazil

ABSTRACT: The scientific and economic importance of soybean root rot justifies the study of this disease, especially the role of insects as dispersers in the spread of root pathogens. The objective was to identify and evaluate qualitatively and quantitatively the role of Cyclocephala modesta, Dyscinetus gagatesand Diloboderus abderus(Coleoptera: Melolonthidae) in the dispersion of root pathogens in cultivated fields. The fungi were identified to the species level with DNA extraction and sequencing of these organisms within Melolonthidae larvae. Larvae were dissected and separated into the parts: mouth parts, prothorax, cuticle and digestive tract (alimentary canal). The Internal Transcribed Spacer region of the rRNA was amplified and compared to sequences deposited in GenBank. This is the first record of dispersion Fusarium oxysporumby Cyclocephala modesta, Dyscinetus gagatesand Diloboderus abderus (Coleoptera: Melolonthidae) under soybean in Brazil.

First report of the occurrence of Ophiocordyceps melolonthae (Ascomycota: Hypocreales: Ophiocordycipitaceae) in larvae of Diloboderus abderus Sturm (Coleoptera: Melolonthidae) in Brazil

This note is the first report on the infection of Diloboderus abderus Sturm (Coleoptera: Melolonthidae) larvae by the fungusOphiocordyceps melolonthae (Hypocreales: Ophiocordycipitaceae) in subtropical Brazil. Identification was made possible by extraction and sequencing of the fungal DNA that was covering the larvae’s mouthparts, prothorax, cuticle, and digestive tract (alimentary canal). Amplification, sequencing and comparison of the ITS region of the ribosomal DNA with voucher sequences of GenBank were performed and were 95% similar to Ophiocordyceps melolonthae. The fungus is an entomopathogen which attacks Melolonthidae larvae, having scientific and economic importance because of the need for increased knowledge on its distribution and on alternatives for biological control of white grubs.

Ecological Characterization of White Grubs (Coleoptera: Melolonthidae) Community in Cultivated and Noncultivated Fields.

Comparative studies on the density and diversity of white grubs community (Coleoptera: Melolonthidae) occurring in cultivated and noncultivated fields of the Planalto region of the state of Rio Grande do Sul, Brazil, are presented. Sampling was carried out in 23 municipalities during the 2009 and 2010 winter seasons. Cultivated and noncultivated fields were chosen in each locality. Melolontid larvae were collected for identification and counted to determine the population density. A mean of 12.9larvaem(-2) were collected in cultivated areas against 10.5larvaem(-2) in noncultivated areas. The latter were more diverse (H' = 2.52) than cultivated areas (H' = 2.26). Despite the high evenness index (J = 0.75 noncultivated and J = 0.74 cultivated), faunistic parameters indicated Cyclocephala flavipennis Arrow and Diloboderus abderus Sturm as an extremely dominant species in cultivated areas. These results showed that the population density of white grubs increases, and their community composition is affected in cultivated areas.

White grubs (Coleoptera, Melolonthidae) in the "Planalto Region", Rio Grande do Sul state, Brazil: Key for identification, species richness and distribution

White grubs (Coleoptera, Melolonthidae) in the "Planalto Region", Rio Grande do Sul state, Brazil: Key for identification, species richness and distribution. The objective of this study was to survey the occurrence and geographic distribution of white grub species (Coleoptera, Melolonthidae) in cultivated and non-cultivated fields of the "Planalto Region", Rio Grande do Sul state, Brazil and develop a key at genus-level. Twenty-eight species from 15 genera and three subfamilies were recorded: Dynastinae, Melolonthinae and Rutelinae. The species or genera recorded for the first time in the state are: Cyclocephala metrica, C. tucumana, Isonychus albicinctus, Liogenys bidenticeps, L. fusca, L. obesa and L. sinuaticeps, Paranomala violacea, as well as unidentified species of Amononyx, Dicrania, Leucothyreus, Macrodactylus, Plectris and Rhizogeniates. Among the species recorded, 23 were associated with winter crops. Only Cyclocephala metrica, Dyscinetus rugifrons, two species of Leucothyreus and one species of the tribe Sericini were not present in cultivated crop fields. Cyclocephala flavipennis and Diloboderus abderus occurred in most of the municipalities sampled, often associated with Plectris sp., C. modesta and C. putrida. The highest richness of melolonthids was concentrated in the northeast of the Planalto region.

Uso da geoestatística para caracterização da distribuição espacial de larvas de 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.

Hexamermis paranaense new species (Nematoda, Mermithidae): a parasite of Diloboderus abderus (Coleoptera, Scarabaeidae) in Argentina

A new species, Hexamermis paranaense n. sp. (Nematoda, Mermithidae), a parasite of larvae of Diloboderus abderus Sturm, 1826 (Coleoptera, Scarabaeidae) is described and illustrated. This new species is characterized by amphids small, amphidial opening pocket-shaped, the anterior portion of the vagina muscularized and slightly protruding with a descending branch forming a loop before joining the uterus, and three rows of genital papillae: the ventrolateral divided in two rows with eight papillae in the outer row and with six papillae in the inner one; the ventral row with four pairs and one single preanal papillae, and with two pairs, a triplete, one pair, a single and one pair postanal papillae.

Danos provocados por coró-das-pastagens em plantas de eucalipto

Esta nota tem por objetivo relatar o ataque de larvas do coró-das-pastagens, Diloboderus abderus Sturm, 1826 (Coleoptera: Melolonthidae), em mudas de eucalipto híbrido (Eucalyptus grandis x Eucalyptus urophylla), na fazenda Bazana, município de Manoel Viana, Rio Grande do Sul. Essa praga se alimentou da casca das plantas na região do coleto, provocando “anelamento” das mudas. A mortalidade de mudas foi de 30% em 40ha. Este é o primeiro registro dos danos desse inseto em plantas de eucalipto no Brasil.

CONTROLE DE LARVAS DE Diloboderus abderus COM INSETICIDAS EM TRIGO

A larva de Diloboderus abderus Sturm (Coleoptera: Melolonthidae) é uma praga importante da cultura do trigo (Triticum aestivum L.) em plantio direto na região Sul do Brasil. Este estudo teve como objetivo avaliar diferentes inseticidas aplicados nas sementes (fipronil e tiametoxam) e via pulverização do solo (clorpirifós e lambdacialotrina) para o controle dessa praga. A eficiência dos inseticidas foi determinada através do número de larvas vivas no solo aos 30, 60 e 90 dias após a emergência das plantas (DAE), da massa seca da parte aérea das plantas aos 90 DAE e da produção de grãos. Foram observadas correlações negativas significativas entre a dose dos inseticidas fipronil e tiametoxam e o número de larvas, e correlações positivas significativas entre estes inseticidas e a massa seca da parte aérea e a produtividade de grãos. Infestações de larvas nas testemunhas não tratadas reduziram a produtividade em relação às áreas tratadas com inseticidas. A produtividade incrementou à medida que aumentou a eficiência de controle do inseto pelos inseticidas. Concluiu-se que clorpirifós (960 e 1200g i.a./ha) e lambdacialotrina a 25g i.a./ha (formulação CE), aplicados em pulverização do solo, são eficientes para reduzir a população de larvas de D. abderus, garantindo a produtividade de grãos. Sugerem-se novos testes com os inseticidas fipronil, tiametoxam e lambdacialotrina (formulação SC) para determinar doses técnica e economicamente adequadas para o controle de larvas de D. abderus em trigo.

Una nueva especie del género Severianoia (Schwenk) (Nematoda: Thelastomatidae) parásita de Diloboderus abderus Sturm (Coleoptera: Scarabaeidae) en Argentina

Severanoia brevicauda n. sp., a parasite of larvae of Diloboderus abderus in Argentina, is described and illustrated. It can be characterized by having the vulva situated at the posterior middle of the body, the eggs without sculpture, the male with three pairs of genital papillae of which one pair is preanal and two pairs postanal. The tail appendage in both sexes is short.

Tamanho e número de unidades de amostra de solo para amostragem de larvas de Diloboderus abderus (Sturm) (Coleoptera: Melolonthidae) em plantio direto

O estudo foi realizado numa lavoura de aveia preta "Comum RS" (Avena strigosa) com cinco anos de plantio direto, em Latossolo Vermelho Escuro, textura argilosa, no município de Cruz Alta, RS, objetivando determinar o tamanho e o número de unidade de amostra de solo para amostragem de larvas de 3° ínstar de Diloboderus abderus (Sturm). O melhor tamanho de unidade de amostra foi 25 x 25 cm, escavadas a 30cm de profundidade, considerando vários critérios, como a análise estatística, o número médio de larvas, o tempo requerido para extração da amostra e a precisão relativa líquida. Os resultados evidenciaram heterogeneidade na distribuição de larvas do inseto, sendo necessárias 67 e 419 amostras para um nível de erro de baixa precisão (25%) e de alta precisão (10%) da média, respectivamente, para oferecer estimativa da população de larvas com uniformidade aceitável.

Níveis de controle de Diloboderus abderus (Sturm) em trigo no plantio direto

Este trabalho foi conduzido nas safras agrícolas de 1991, 1992 e 1994, em Cruz Alta, no Rio Grande do Sul. O objetivo foi avaliar níveis de infestação e danos de Diloboderus abderus (Sturm) em trigo no plantio direto. Infestações a partir de 5,0 larvas/m² causaram reduções significativas na produtividade das plantas de trigo em relação a testemunha não infestada. Aumentando o número de larvas/m² ocorre danos nas plantas e, conseqüentemente, decresce a população de plantas, o número de espigas, a massa seca da parte aérea e a produtividade. Os níveis de controle obtidos foram de 5,4 larvas/m² (1991), 3,0 larvas/m² (1992) e 6,1 larvas/m² (1994). Foram observadas correlações negativas significativas do número de larvas com a população de plantas, o número de espigas, a massa seca da parte aérea e a produtividade, e correlações positivas significativas da produtividade com a população de plantas, o número de espigas e a massa seca da parte aérea. Baseado nos danos produzidos pelo inseto, sugere-se o nível de controle de 5,0 larvas/m² como indicador para tratamento de sementes de trigo com inseticidas.

DESCRIPCION DE LOS ESTADOS INMADUROS Y NOTAS SOBRE LA BIOLOGIA DE DILOBODERUS ABDERUS (STURM, 1826) Y PHILOSCAPTUS BONARIENSIS (BURMEISTER, 1847) COLEOPTERA: MELOLONTHIDAE, DYNASTINAE)

Se describe e ilustra las larvas de tercer estadio y las pupas de Diloboderus abderus (Sturm) y Philoscaptus banariensis (Burm.), y se comentan las características etológicas más importantes de cada una, así como los daños que causan en cultivos y pradera.

Controle de larvas de Diloboderus abderus Sturm (Coleoptera: Melolonthidae) via tratamento de sementes de trigo com inseticidas em plantio direto

A larva de Diloboderus abderus Sturm (Coleoptera: Melolonthidae) é uma praga importante da cultura do trigo (Triticum aestivum L.) em plantio direto na região Sul do Brasil. Este estudo teve como objetivo avaliar doses de diferentes inseticidas aplicados via tratamento de sementes para controle dessa praga. A eficiência dos inseticidas foi avaliada através do número de larvas vivas aos 30, 60 e 90 dias após a emergência das plantas (DAE), da massa seca da parte aérea das plantas aos 90 DAE, do número de espigas aos 120 DAE e da produção de grãos. Foram observadas correlações negativas significativas da dose dos inseticidas com o número de larvas, e correlações positivas significativas entre dose dos inseticidas e massa seca da parte aérea e número de espigas. Infestações de larvas nas testemunhas não tratadas causaram reduções significativas na produtividade em relação às áreas tratadas com inseticidas. A produtividade aumentou à medida que se aumentou a dose dos inseticidas. Embora imidaclopride não se tenha mostrado muito eficiente na redução da população de larvas de D. abderus, doses a partir de 350, 320, 125 e 42 g i.a./100 kg de sementes dos inseticidas tiodicarbe, furatiocarbe, carbossulfam e imidaclopride, respectivamente, foram eficientes na redução das perdas na produtividade do trigo em plantio direto, sob infestações iniciais variando entre 18 e 26 larvas/m².

Aspectos biológicos, danos e controle de Diloboderus abderus sturm, 1826 (Coleoptera: melolonthidae) em plantio direto

Studies were carried out in the counties of Cruz Alta and Fortaleza dos Valos, Rio Grande do Sul State, in an Oxissol (Dark-Red Latosol), from January 1990 to February 1994, aiming to determine the biological aspects, damage and control of Diloboderus abderus (Sturm) and looking for integrated management altemative practices in commercial fields cultivated under no-tillage system. In the field it was determined that D. abderus had one generation during the year, with the stages occurring within the soil profile in well defined dates. Adults show up from November to April, eggs from January to April, larvae from February to November and pupae from October to December. The female flying back, which occurs in the crepusculum and beginning of the night is an important surviving mechanism of this species, where new reproduction places are searched for. Adequate amount of cultural residues on the soil surface during the reproductive period of the insect (January to March) is an important reproductive and alimentary resource used by the adult female to build its nest, protect the eggs and nourish the new-bom larvae. Thus, the workability of strategies to reduce larvae populations for subsequent winter crops can come true with winter crops succession, such as rye-grass, rape, vetch or lupine and summer crops, such as corn, which is normally sown in September or October, in substitution to black oats-soybean traditionally used in the region, since those crops allow a smaller amount of residues on the soil during the reproductive period, thus disfavouring the female oviposition. The larval phase have three instars and, in ther active period, from May to September, are characterized by the economical damage that they cause to the root system of plants. When the soil is covered with black oats, the spatial distribution of larvae occurs in different ways depending on the size of the soil sample. The predominant spatial distribution was of a negative binomial, indicating that the larvae show aggregation. The sample size units which showed to be more efficient were 25 x 25 and 25 x 50cm, of soil dug to a depth of 30cm. It is suggested that 33 soil sample units of 25 x 50cm and 67 of 25 x 25cm, for 25% precision of the average value, offer an evaluation of the larvae population with an acceptable uniformity. The control level determined is of 5.4 larvae/m2 for wheat plants and 0.14 larva/m2 for com plants. The no-tillage, so important to soil conservation, can be continued in soils infested with larvae of D. abderus when associated to seed treatment of wheat or corn with insecticides. Another clear possibility of controlling larvae of this insect is to delay the sowing of corn, starting me operation not before the beginning of October.