Jerson Vanderlei Carús Guedes

Weevils Injurious for Roots of Citrus in São Paulo State, Brazil

Ten species of broad nosed weevils belonging to Entiminae, Naupactini, are recorded as harmful for roots of citrus in Sao Paulo state, Brazil. Most species belong to Naupactus Dejean, N. rivulosus (Olivier), N. tarsalis Boheman, N. curtus Boheman, N. navicularis Boheman, N. versatilis Hustache, N. ambiguus Boheman, and N. cervinus Boheman; one species was assigned to Teratopactus Heller, T. nodicollis (Boheman); one to Parapantomorus, P. fluctuosus Schoenherr (Boheman) and one to Symmathetes Schoenherr (a genus herein reinstated), S. kollari Schoenherr. Larvae live in soil and bore on roots of the trees, causing more damages than adults, that feed on leaves. The main goal of this paper is to provide a key, diagnosis and habitus photographs of the species, in order to facilitate their identification. We also provide information on their geographic range in Brazil and previous plant associations, and we discuss some relevant biological features, especially those related to oviposition habits.

Wolbachia infection in the tribe Naupactini (Coleoptera, Curculionidae): association between thelytokous parthenogenesis and infection status.

Several parthenogenetic species of broad‐nosed weevils exist, some of them of economic importance because of their pest status. Screening of the maternally inherited Wolbachia bacterium in 29 weevils of the tribe Naupactini, using multilocus sequence typing allowed us to assess a significant correlation between asexuality and infection, and suggests an involvement of Wolbachia in the origin of this reproductive mode. The nine Wolbachia strains retrieved from the Naupactini belong to the B supergroup. Phylogenetic analysis of these strains, along with other 23 strains obtained from arthropods and nematodes, supports previous hypotheses that horizontal transfer of Wolbachia amongst species from unrelated taxa has been pervasive.

Spider mites associated to soybean in Rio Grande do Sul, Brazil

The objective of this work was to study the occurrence and geographic distribution of phytophagous mites associated to soybean in Rio Grande do Sul, Brazil. Samplings were performed from January to May 2005 on genetically modified soybean (glyphosate-tolerant) crops, in 27 municipalities of six regions - Alto Vale do Uruguai, Campanha, Depressao Central, Planalto Medio, Missoes and Serra do Sudeste. Five phytophagous mite species belonging to the family Tetranychidae - Mononychellus planki, Tetranychus desertorum, T. gigas, T. ludeni and T. urticae - occurred in 21, 12, 5, 3 and 14 municipalities, respectively. A map of Rio Grande do Sul with the geographic distribution of each species is presented, as well as an illustrated dichotomous key to help the identification of the spider mites found.

Mites associated with soybean crop in Rio Grande do Sul State, Brazil.

During the last growing seasons, high infestations of phytophagous mites were observed in the State of Rio Grande do Sul, Brazil, becoming necessary to apply pesticides for their control. The objective of this study was to identify phytophagous and predatory mite species associated with soybean in ten counties of that state, during the 2002/03 and 2003/04 growing seasons, in five soybean cultivars (A 6001 RG, A 7001 RG, A 8000 RG, A 8100 RG, Anta 82), all genetically modified. In samples of soybean leaves four phytophagous mite species (Mononychellus planki (McGregor), Polyphagotarsonemus latus (Banks), Tetranychus desertorum Banks and Tetranychus gigas Pritchard & Baker) and two predatory mite species (Phytoseiulus fragariae Denmark & Schicha and Typhlodromalus aripo De Leon) were found. T. desertorum was found for the first time associated with soybean in the country. Phytoseiulus fragariae and T. aripo are reported for the first time on soybean. The potential of phytoseid mites as biological control agents in soybean crop was discussed. Among the hypotheses to explain the increasing infestation of soybean fields with phytophagous mites area are the progressively larger cultivated area, the dry spells observed in the last few years in the growing season, changes in soybean cropping system that led to increased use of pesticides and utilization of new soybean cultivars with morphological or biochemicals characteristics that favour the development of these mite populations.

Chave de identificação, ocorrência e distribuição dos curculionídeos-das-raízes dos citros em São Paulo e Minas Gerais

The objective of this paper is to bring about a diagnosis of four species of root weevils, recorded for the first time causing damage in citrus grooves of the states of Sao Paulo and Minas Gerais, Brazil. A key for the identification of 14 species harmful for citrus in these states is provided as well as a study on their occurrence and distribution. The four species treated in this paper belong to the genus Naupactus Dejean (Curculionidae: Entiminae: Naupactini): N. bellus Boheman, N. cinerosus Boheman; N. decorus (Fabricius) and N. virens Boheman. Among the 14 species included in the key, eleven belong to Naupactus [N. ambiguus Boheman, N. bellus Boheman, N. cervinus Boheman, N. cinerosus Boheman; N. curtus Boheman, N. decorus (Fabricius), N. navicularis Boheman, N. rivulosus (Olivier), N. tarsalis Boheman, N. versatilis Hustache and N. virens (Boheman); one to Teratopactus Heller (T. nodicollis (Boheman)]; one to Parapantomorus Emden [P. fluctuosus (Boheman)] and one to Symmathetes (S. kollari Schoenherr). The citrus root weevils occur in all citrus grooves of Sao Paulo and Minas Gerais, and the species diversity is higher in the center-south area of Sao Paulo. N. tarsalis, N. versatilis and P. fluctuosus are present in the highest number of localities.

Estimativa da área de folhas de cultivares antigas e modernas de soja por método não destrutivo

The objective of this study was to determine an empirical mathematic model for estimating leaf area of different soybean cultivars from leaf dimensions, with emphasis to modern and currently used soybean cultivars used in Rio Grande do Sul. A field experiment conducted at Santa Maria during three growing seasons (2010/2011, 2012/2013 e 2013/2014) and 13 soybean cultivars (NS 4823 RR, BMX Energia RR, Igra RA 518 RR, BMX Turbo RR, NA 5909 RG, TMG 7161 RR Inox, TEC 5936IPRO, IAS 5, BMX Potencia RR, Fepagro 36 RR, BRS 246 RR, Bragg e CD 219 RR) was used. Twenty leaves of each cultivar were used for calibrating the model and another 50 leaves were used for testing the predictive capacity of the model as independent data. The model is based on the length (L) and the greatest width (W) of the central foliole of trifoliolate leaf. The relationship between leaf area and the linear dimensions of the central foliole was fitted to a linear model for each cultivar as well as to a generalized model for all cultivars. The predictive capacity of the equations was evaluated with the statistics root mean square error, BIAS, modified index of agreement and coefficient r. The results indicate that the non destructive method, based on linear dimensions of the central foliole is appropriate for estimating the area of individual leaves in soybean and that the general equation LA = 2,0185.(L.W) can be used for several modern soybean cultivars.

Selection, isolation, and identification of fungi for bioherbicide production

Production of a bioherbicide for biological control of weeds requires a series of steps, from selection of a suitable microbial strain to final formulation. Thus, this study aimed to select fungi for production of secondary metabolites with herbicidal activity using biological resources of the Brazilian Pampa biome. Phytopathogenic fungi were isolated from infected tissues of weeds in the Pampa biome. A liquid synthetic culture medium was used for production of metabolites. The phytotoxicity of fungal metabolites was assessed via biological tests using the plant Cucumis sativus L., and the most promising strain was identified by molecular analysis. Thirty-nine fungi were isolated, and 28 presented some phytotoxic symptoms against the target plant. Fungus VP51 belonging to the genus Diaporthe showed the most pronounced herbicidal activity. The Brazilian Pampa biome is a potential resource for the development of new and sustainable chemical compounds for modern agriculture.

Managing the sugarcane borer, Diatraea saccharalis, and corn earworm, Helicoverpa zea, using Bt corn and insecticide treatments.

Abstract The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) and the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are important pests of corn in Brazil and have not been successfully managed, because of the difficulty of managing them with pesticides. The objective of this study was to evaluate the effect of Bt corn MON810, transformed with a gene from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) insecticide seed treatment, and foliar insecticide spray using treatments developed for control of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is the major pest of corn. The experiments were done under field conditions in early- and late-planted corn in the state of Rio Grande do Sul, Brazil, and in the laboratory. The MON810 corn reduced infestations and damage by D. saccharalis and H. zea. The insecticides used in seed treatments or foliar sprays did not affect D. saccharalis and H. zea infestations or damage levels. The exception was the insecticide seed treatment in non-transformed corn, which reduced early infestations of D. saccharalis. The MON810 corn, therefore, can be used for managing these two pest species, especially D. saccharalis.

Taxonomic revision and cladistic analysis of Teratopactus Heller (Coleoptera : Curculionidae)

Teratopactus Heller (Entiminae : Naupactini) is a broad-nosed weevil genus widespread in South America. This first taxonomic revision of the genus includes seven species: T. capucinus (Perty) (type species; syn. T. senex (Boheman)); T. elegans (Lucas), comb.nov.; T. gibbicollis (Boheman); T. nodicollis (Boheman) (syn. T. angulicollis (Lucas), T. paulanus (Fonseca & Autuori), T. serripes (Boheman), and T. perpastus (Boheman), syn. nov.); T. retusus (Boheman); T. tuberculatus (Arrow); and T. vittatus (Mannerheim), comb.nov. All species except T. tuberculatus have a strong ovipositor lacking styli, T. elegans, T. nodicollis and T. vittatus show well developed humeri bearing a strong tooth and T. retusus, T. capucinus and T. gibbicollis are characterised by a strongly gibbous pronotum and reduced humeri. Teratopactus nodicollis is the most variable and widespread species (Argentina, Brazil, Bolivia, Paraguay and Uruguay), T. tuberculatus and T. elegans range through Brazil and Paraguay and the remaining species are endemic to Brazil. The first cladistic analysis of the genus Teratopactus plus two outgroups, using 36 morphological characters, established synapomorphies and revealed relationships between the species in a single cladogram with the following topology: (T. tuberculatus ((T. elegans (T. nodicollis– T. vittatus)) (T. retusus (T. capucinus–T. gibbicollis)))).

Eficiência de métodos de amostragem de lagartas e de percevejos na cultura de soja

The aim of this study was to compare the collect capacity of three sampling methods for caterpillars and stink bugs in soybean. Therefore, in a 6.16ha soybean field, a grid of 154 sampling points spaced 20×20m was marked. In each of these 154 points were collected caterpillars (small, large and total) and stink bugs (nymphs, adults and total) (six variables) by the sampling methods beating cloth, wide beating cloth and vertical beat sheet, on 14 phenological stages of the soybean crop, totaling 6,468 samples. For each of these six variables, on each of the 14 phenological stages and overall (all phenological stages), the averages of the three sampling methods were compared by Students t test (bilateral) for paired data, in a 5% probability level. The number of caterpillars collected by the sampling methods decreases in the following order: vertical beat sheet, wide beating cloth and beating cloth. The number of stink bugs collected by the sampling methods vertical beat sheet and wide beating cloth is higher than beating cloth. Vertical beat sheet is the most efficient to collect caterpillars and stink bugs.