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Colombo, Brazil

Finck C.,Grao Limpo | Santana K.,State University of Ponta Grossa | de Oliveira E.B.,Embrapa Floresta | Neto P.H.W.,UEPG | Garcia L.C.,UEPG
Ciencia Rural | Year: 2015

The objective of this study was to determine the shortest time of fumigation to promote the total mortality of adult insects of the genus Sitophilus, in grains of wheat, undergoing fumigation in chamber of tarpaulin. The experiment was carried out in a grain storage unit in Ponta Grossa - PR. The experimental design was completely randomized, with six treatments and ten replications. Treatments consisted of times of exposure of wheat grain fumigation: zero; 12; 36; 60; 84 and 108 hours, in bucket trucks wrapped in tarpaulin (forming the chambers of tarpaulin). It was applied the commercial product Fertox® in tablets form, with the dosage of 6g m-3 in each chamber of 35m³. Repetitions were composed by cages with ten live adult insects of the Sitophilus genus each one, inserted into the grain mass in bucket trucks and arranged at various points and depths. The fitted regression model to describe the insect mortality behavior (M) according to the fumigation time (T) was M=6.6867+93.4694 (1-e0.1645T)26.9607. Equation shows that 58.9h after application of the steam product the insect mortality is of 100%. © 2015, Universidade Federal de Santa Maria. All rights reserved.

Oliveira R.R.,State University of Maringa | Aguiar R.L.,State University of Maringa | Tessmann D.J.,State University of Maringa | Nunes W.M.C.,State University of Maringa | And 2 more authors.
Plant Disease | Year: 2014

Syagrus oleracea (Mart.) Becc. (bitter coconut), a palm tree species that is native to central Brazil, has been increasingly cultivated in this country for heart-of-palm production. Epidemics of a necrotic leaf spot of unknown etiology have been recorded on bitter coconut plants in transplant nurseries and plantation since 2008. The first symptoms appear as small, yellow, hydrotic flecks on young or mature leaves that evolve to necrotic brown streaks that run parallel to the leaf veins. Usually, yellow halos occur around the lesions and hydrosis is common during lesion expansion. Necrotic lesions can reach up to 40 mm in length and 10 mm in width, and the lesions often coalesce, causing extensive tissue damage. During a survey in a 3-year-old bitter coconut plantation in Maringá County (coordinates: 23°23′51.25″ S, 51°57′02.09″ W; elevation: 507 m) in the state of Parana, a dozen symptomatic leaves were collected with the aim of elucidating the etiology of this disease. Conidia and conidiophores typical of Cladosporium were frequently observed on the diseased leaf tissue under natural field conditions as well on the surfaces of disinfected leaf tissues kept in a humid chamber for 48 h at 25 ± 2°C with a 12-h photoperiod. Five monoconidial cultures growing on potato dextrose agar (PDA) medium were obtained from different leaves showing leaf spot symptoms. The cultures were grown on PDA to induce sporulation. At 7 days after incubation at 25 ± 2°C and a 12-h photoperiod, gray to gray-olive colonies were observed. The conidiophores were macronematous, erect, oblong, branched, 1 to 5 septate, and 75.0 to 120.0 × 1.90 to 3.20 μm. The ramoconidia were cylindrical or oblong, 0 to 2 septate, and 28.0 to 40.0 × 2.8 to 3.6 μm, with a truncate base of 1.9 to 2.2 μm; secondary ramoconidia were cylindrical or oblong, 0 to 2 septate, 8.0 to 31.0 × 2.2 to 3.1 μm, with 3 to 5 distal conidial hila; intercalary 1-septate conidia were 5.5 to 17.0 × 2.1 to 3.4 μm, with 1 to 3 distal conidial hila; terminal 1-septate conidia were catenulate and 2.2 to 4.2 × 1.8 to 3.1 μm. Species identification was performed based on morphology and DNA sequence data (1). Portions of the elongation factor 1α (551 bp; TEF) and actin (213 bp; ACT) genes were amplified by PCR. A BLAST search of the GenBank database revealed that the TEF (KC484658 to KC484662) and ACT (KC484663 to KC484667) sequence fragments from isolates Gua1, Gua2, Gua3, Gua4, and Gua5 had 100% identity with the accessions HM148616 and HM148371 of Cladosporium perangustum (1). Isolates were tested for pathogenicity against bitter coconut. Ten potted plants with 4 to 6 fully expanded leaves were inoculated with each isolate by spraying a suspension of conidia (105 spores per ml) onto leaves until runoff using a handheld spray bottle. Non-inoculated controls (10 plants) were sprayed with distilled water. The plants were kept in a humid plastic chamber at 20 to 26°C. All examined isolates were pathogenic to bitter coconut, causing symptoms identical to those described above 12 days after inoculation. All inoculated tissues were plated onto PDA to confirm the presence of the pathogen. Live cultures are being maintained at the Micoteca/URM/UFPE (www.ufpe.br/micoteca), Brazil. To our knowledge, this is the first report of a disease caused by C. perangustum on S. oleracea worldwide, and the study provides valuable plant disease diagnostic information for the palm hearth industry in Latin America.

Ramos M.R.,Federal University of Parana | Favaretto N.,Federal University of Parana | Dieckow J.,Federal University of Parana | Dedeck R.A.,Embrapa Floresta | And 3 more authors.
Journal of Agriculture and Rural Development in the Tropics and Subtropics | Year: 2014

Agricultural systems with conventional tillage and intensive use of agrochemicals, especially those on high slopes and with shallow soils, have the potential to release pollutants. This study aimed at evaluating the soil, water and nutrient lost via agricultural runoff in large plots (small catchments) under conventional and organic farming of vegetables as well as under forest (control) system in a Cambisol in the Campestre catchment. Samples of runoff were collected biweekly for one year through a Coshocton wheel. The soil and water losses from the conventional farming were 218 and 6 times higher, respectively, than forest. Under organic farming the soil and water losses were 12 and 4 times higher, respectively, than forest. However the soil losses (0.5 to 114 kg ha-1 year-1) are considered low in agronomy but environmentally represent a potential source of surface water contamination by runoff associated pollutants. The concentrations and losses of all forms of phosphorus (P) were higher in the conventional system (9.5, 0.9 and 0.3mg L-1 of total P for conventional, organic and forest systems, respectively), while the organic system had the highest concentrations and losses of soluble nitrogen (4.7, 38.6 and 0.4mg L-1 of NO3-N, respectively). The percentage of bioavailable P was proportionally higher in the organic system (91% of total P lost was as bioavailable P), indicating greater potential for pollution in the short term.

de Godoy R.C.B.,Embrapa Floresta | Waszczynskj N.,Federal University of Parana | Santana F.A.,Federal University of Reconcavo da Bahia | e Silva S.O.,Embrapa Mandioca e Frutas | And 2 more authors.
Ciencia Rural | Year: 2016

Cultivated bananas have very low genetic diversity making them vulnerable to diseases such as black-Sigatoka leaf spot. However, the decision to adopt a new banana variety needs to be based on a robust evaluation of agronomical and physicalchemical characteristics. Here, we characterize new banana varieties resistant to black-Sigatoka leaf spot and compare them to the most widely used traditional variety (Grand Naine). Each variety was evaluated for a range of physic-chemical attributes associated with industrial processing and flavor: pH, TTA, TSS/ TTA, total sugars, reducing sugars and non-reducing sugars, humidity, total solids and yield. The Thap Maeo variety had the highest potential as a substitute for the Grand Naine variety, having higher levels of total soluble solids, reducing sugars, total sugars and humidity. The Caipira and FHIA 2 varieties also performed well in comparison with the Grand Naine variety. Cluster analysis indicated that the Grand Naine variety was closely associated with varieties from the Gross Michel subgroup (Bucaneiro, Ambrosia and Calipso) and the Caipira variety, all of which come from the same AAA genomic group. It was concluded that several of the new resistant varieties could potentially substitute the traditional variety in areas affected by black-Sigatoka leaf spot disease. © 2016, Universidade Federal de Santa Maria. All rights reserved.

Caixeta M.P.,State University of Maringa | Nunes W.M.C.,State University of Maringa | dos Santos A.F.,Embrapa Floresta | Tessmann D.J.,State University of Maringa | Vida J.B.,State University of Maringa
Summa Phytopathologica | Year: 2013

Citrus root rot is considered a disease of great importance to citriculture in Brazil and around the world. The etiology of this disease comprises a complex of Phytophthora species. Although citrus root rot is important, little is known about it in the producing regions of Paraná State, Brazil. Therefore, this study aimed to identify Phytophthora species associated with root rot in citrus orchards in Paraná. In the North and Northwest regions of this state and in Vale do Ribeira, samples were collected from the roots of plants showing symptoms of citrus root rot, as well as from the rhizosphere soil. In the laboratory, employing pear cv. D'anjou as bait and the culture medium potato-dextrose-agar, 21 isolates of Phytophthora spp. were obtained. All isolates infected seedlings of Rangpur lime, reproducing the symptoms of root rot and presenting mycelial growth at 8 °C and 36 °C, except for the isolate PR20 at 36 °C. In vitro, these isolates were heterothallic, and 20 of them were compatible with the standard type A2, while one of them was compatible with the standard type A1. Twenty isolates formed papillate persistent sporangia of 25.5 - 62.0 μm length (C) and 27.9 - 49.6 μm width (L); the C/L ratio was 1.38:1. One isolate (PR20) had sporangia of 40.3 - 55.8 μm length and 27.9 - 37.2 width, forming papillale or bipapillate persistent sporangia of distorted forms and not forming chlamydospores. The optimum temperature for the growth of this isolate was between 20 and 28°C, while for the remaining isolates it was from 24 to 32°C; the latter had abundant production of globose chlamydospores with diameter ranging from 21.7 to 43.4 μm. According to the presented morphophysiological characteristics, of the 21 analyzed isolates, 20 belonged to the species P. nicotianae and one to the species P. citrophthora. Sequence analysis of genes of the rDNA ITS1-5.8SITS2 region, using the test Single-Strand Conformation Polymorphism (SSCP), confirmed P. nicotianae and P. citrophthora as the two Phytophthora species associated with root rot in citrus orchards in the state of Paraná.

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