Insecticide resistance in populations of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), from the state of Pernambuco, Brazil.

The diamondback moth Plutella xylostella (L.) has a great economic importance in Brassicaceae crops in many parts of the world. Recurrent infestations of this pest in growing areas of Pernambuco state, Brazil, have led farmers to frequently spray their crops with insecticides. However, control failures by several insecticides have been alleged by farmers. The objective of this study was to check whether resistance to insecticides could explain these control failures in P. xylostella. Populations of P. xylostella from Pernambuco were collected between January and April 2009. The resistance ratios of P. xylostella populations were compared among five different active ingredients: abamectin, methomyl, lufenuron, indoxacarb, and diafenthiuron by leaf dipping bioassays using foliar discs of kale leaves. Mortality data were submitted to probit analysis. The P. xylostella populations showed variable response and significant resistance to one or more insecticides. The population from Bezerros County exhibited the highest resistance ratios to indoxacarb (25.3 times), abamectin (61.7 times), and lufenuron (705.2 times), when compared to the reference population. The populations from Bonito and Jupi Counties were 33.0 and 12.0 times more resistant to lufenuron and abamectin, respectively, when compared with the reference population. Resistance to methomyl was the least common, but not less important, in at least four populations. These results indicated that control failures were associated with resistance by some of the evaluated insecticides, reinforcing the need for resistance management in areas of the state of Pernambuco.

Oral subchronic toxicity of aqueous crude extract of Plantago australis leaves.

The toxic effects of chronic oral administration (60 days) of aqueous crude extract (AE) of Plantago australis Lam. (Plantaginaceae) in rats at doses of 850 and 1700 mg/kg on biochemical (ALT, AST, creatinine, urea, glucose, alkaline phosphatase, total proteins and albumin), hematological (complete hemogram), and histopathological (heart, lung, liver, kidney, esophagus, stomach and gut) parameters were studied. All biochemical and hematological parameters were found to be in the normal range, but ALT in animals that received AE of 850 mg/kg was higher. Histopathological analysis of organs, especially the liver did not present alterations.

Classification of breast tissue by electrical impedance spectroscopy.

Electrical impedance spectroscopy is a minimally invasive technique that has clear advantages for living tissue characterisation owing to its low cost and ease of use. The present paper describes how this technique can be applied to breast tissue classification and breast cancer detection. Statistical analysis is used to derive a set of rules based on features extracted from the graphical representation of electrical impedance spectra. These rules are used hierarchically to discriminate several classes of breast tissue. Results of statistical classification obtained from a data set of 106 cases representing six classes of excised breast tissue show an overall classification efficiency of approximately 92% with carcinoma discrimination > 86%.