Pseudopestalotiopsis elaeidis associated with leaf spots on Cycas revoluta in Brazil

Cycas revoluta (Cycadaceae) is commonly cultivated as an ornamental tree in several countries. In April 2015, C. revoluta leaves showing brownish spots with a yellow halo that progressed to leaflet necrosis were observed in Belém, Pará state, Brazil. This study aimed to determine the aetiology of this disease on sago palm in Brazil. Based on DNA sequence-based phylogeny, morphology, and colony characterization, the fungus was identified as Pseudopestalotiopsis elaeidis. To the best of our knowledge, this is the first report of P. elaeidis associated with leaf spots on C. revoluta worldwide.     

Araucaria angustifolia (Bert.) O. Kuntze induces oxidative and genotoxic damage in larvae of Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae)

Plant-derived products have been considered as an important alternative to common pesticides. Araucaria angustifolia extract (AAE) contains high levels of polyphenols, which are correlated with mortality in defoliating insects. Therefore, this study aimed to evaluate the effects of AAE treatments on A. gemmatalis larvae. Results showed that AAE was able to induce lipid, protein, and DNA damage in the larvae via oxidative stress. AAE treatment did not induce larvae mortality; however, there was an increase in the number of malformed pupae, along with a decrease in the emergence of the insects. These biological effects may be correlated with the polyphenol content of the AAE.     

Comparison of the external morphology of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) ticks from Brazil and Argentina

In the present study the external morphology of semi-engorged Rhipicephalus sanguineus females ticks from Brazil and Argentina were compared by scanning electron microscopy. Many differences were detected among the R. sanguineus collected at the two localities, such as body size, shape of the genital pore, and morphology of the sensory structures. All these characteristics are fundamental for the diagnosis of species of the genus Rhipicephalus and thus indicate the need for further comparisons and, the taxonomical revision of this species of tick in the Neotropics.     

Morphological characterization of the ovary and vitellogenesis dynamics in the tick Amblyomma cajennense (Acari: Ixodidae)

In this work we describe the internal morphology of the female reproductive system of the cayenne tick Amblyomma cajennense. This system is represented by a panoistic ovary, which lacks nurse cells in the germarium. This ovary consists of a single tube, in which a large number of oocytes develop asynchronously, thus accompanying the processes of yolk deposition in the oocytes. The oocytes were classified into stages that varied from I to V, according to: cytoplasm appearance, presence of the germ vesicle, presence of yolk granules, and presence of chorion. The study of vitellogenesis dynamics suggest that the yolk elements are deposited in the oocyte following a preferencial sequence, in which the lipids are the first to appear, followed by proteins an finally by the carbohydrates. In this way the yolk of A. cajennense ticks have these three elements that may be free in the cytoplasm or chemically bounded forming glycoprotein or lipoprotein complexes.     

Development of a methodology for calcium, iron, potassium, magnesium, manganese, and zinc quantification in teas using X-ray spectroscopy and multivariate calibration

In this study an analytical methodology for food analyses combining X-ray spectroscopy (XRS) with partial least-squares (PLS) data treatment was developed. Fifteen tea samples were purchased at a local market, and XRS spectra were obtained without sample pretreatment. For comparison of the metal concentrations, the samples were also mineralized, and six elements were determined using flame atomic absorption spectrometry (Ca, Fe, Mg, and Mn), flame atomic emission spectrometry (K), and thermospray flame furnace atomic absorption spectrometry (Zn). The spectral information obtained from XRS and the metal concentrations found using the alternative techniques were employed to generate six PLS models. The Ca and Mn models required four latent variables (LV), Fe, five LV, K, two LV, and Mg and Zn, three LV. The limits of quantification for these models were 614, 134, 761, 140, 85, and 1 mg kg(-1) for Ca, Fe, K, Mg, Mn, and Zn, respectively.     

Structural and cytochemical changes in the salivary glands of the Rhipicephalus (Boophilus) microplus (CANESTRINI, 1887) (Acari: Ixodidae) tick female during feeding

This study describes the morphology of salivary glands of Rhipicephalus (Boophilus) microplus female ticks at beginning of feeding (24-48 h of attachment) and semi-engorged (4-5 days of attachment) to verify the degenerative characteristics of these organs and the secretory phase in which the process begins. At the beginning of feeding, secretion granules had been observed only in the cytoplasm of cells b, c1, c2, c4 (type II acinus) and d (type III acinus), as well as large nuclei with regular and preserved morphology. In the semi-engorged females the acini presented few normal cells, few partially preserved ones, and the remaining ones in several stages of degeneration, that is, with retraction and cytoplasmic vacuolization, and nuclei with chromatin in several stages of condensation, picnotic and/or in fragmentation. In type I acinus and in the excretory ducts of the studied glands, at both feeding stages, no degenerative characteristic was observed. In females of R. (B.) microplus, the salivary glands degenerate asynchronically and precociously when compared with those of others tick's species.     

Occurrence of Raoiella indica Hirst (Acari,Tenuipalpidae) in the Southeast region of the state of Pará, Brazil

Journal of Plant Diseases and Protection - The red palm mite Raoiella indica Hirst attacks coconut, banana and açai trees. In 2007, the mite was recorded for the first time in South America....     

Genetic control of Asian rust in soybean

The objective of this study was to investigate the genetic mechanisms of soybean resistance to Asian rust (Phakopsora pachyrhizi Syd. & P. Syd). F2 and F3 generations from 15 diallel crosses involving six soybean cultivars, FT-2, EMBRAPA 48, BRS 154, BRS 184, BRS 214, BRS 231, were used to analyze the genetic control of Asian rust resistance in the soybean parents tested. Genetic models were fitted to means and variances of the generations tested in a completely randomized field experiment with 5,700 hill plots. The experiment was spray-inoculated twice with an isolate that was first detected during the 2002/03 season in Mato Grosso (MT) State and presently prevail in Central Brazil, at a six-day interval, on borders rows and on the useful area, respectively, with a 10⁴ spores/ml distilled H₂O suspension. Assessments were made using a diagrammatic scale for disease severity at seven and 39 days after the first detection of Asian rust in the experiments. Evaluations made in the second assessment (39 days) discriminated better between genotypes. Selection at early plant developmental stages may not result in adult resistant plants. Cultivar FT-2, which had presented monogenic resistance to a rust isolated that prevailed in the first two years of rust occurrence in Brazil, showed no resistance to the MT State rust strain used in this experiment, but eleven crosses showed genetic variability for resistance in the second assessment. Soybean rust resistant genes showing predominantly additive effects are dispersed among parents. Narrow sense heritability values ranging from 0.42 to 0.74 at the F3 family level in the second assessment suggested that selection of resistant genotypes is feasible.