The chemical composition of essential oil of leaves of Piper aduncum L., growing wild in a fragment of the Atlantic Rainforest biome in northeastern Brazil, was determined through gas chromatography-mass spectrometry. The acaricidal activity and repellency of the essential oil and its components [dillapiole (0.28 g/ml), α-humulene (0.016 g/ml), (E)-nerolidol (0.0007 g/ml) and β-caryophyllene (0.0021 g/ml)] were evaluated in the laboratory against adults of Tetranychus urticae Koch. The mites were more susceptible to the oil in fumigation tests (LC(50) = 0.01 μl/l of air) than in contact test with closed Petri dish (LC(50) = 7.17 μl/ml); mortality was reduced by approximately 50 % in the latter test. The repellent action of the oil and toxicity by fumigation and contact did not differ significantly from the positive control (eugenol). The repellent activity was attributed to the components (E)-nerolidol, α-humulene and β-caryophyllene, whereas toxicity by fumigation and contact was attributed to β-caryophyllene. The effect of Piper oil and the role of its components regarding host plant preference with a two-choice leaf disk test are also discussed.

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Deltamethrin is a commonly used insecticide for controlling its key maize pest, the fall armyworm Spodoptera frugiperda (Lep., Noctuidae). Its toxicological profile is well known, but its impact on arthropods widely reported as bioindicators, mainly springtails (Collembola) and mites (Oribatida), is yet to be assessed in tropical maize fields. The treatments used to circumvent this shortcoming were conventional cultivation and no-tillage cultivation (with a presowing application of 2,4-D and glyphosate) systems with or without deltamethrin spraying. The deltamethrin residue analysis of soil samples by gas chromatography did not detect the insecticide 24 h after it was sprayed on the maize fields. There was no significant overall effect of deltamethrin based on principal component analysis. However, repeated-measures analyses of variance detected significant impact of deltamethrin in a species of Nitidulidae (Coleoptera). The cultivation system also provided significant impact on Oribatida and Gamasida soil mites and on the same Nitidulidae species referred above, which were more abundant in the conventional cultivation system. Springtails were also significantly affected by the cultivation system showing greater abundance in the conventional system, except Podumorpha. Analyses using only high taxonomic levels did not allow the detection of impact in the ant assemblage assessed. The results suggest that the impact of deltamethrin on soil arthropods from tropical fields varies among species and is lower than expected. The cultivation system imposes more drastic effects on arthropod assemblage.

Deltamethrin is one of the most frequently used insecticide in Brazilian maize fields aiming to control the fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae). Despite the fact that the toxicology of this insecticide is well known, there is little information about its impact on Neotropical Coleoptera. Therefore our objective was to evaluate the deltamethrin effect on the Coleoptera assemblage associated with maize crops. The treatments used were conventional and no tillage cultivation with or without deltamethrin sprays. There was significant effect of the cultivation system on the species assemblage selected for analysis. The effect of deltamethrin was only detected in the conventional cultivation system, while no significant effect of insecticide spraying was observed on the Coleoptera assemblage associated with the maize crop, suggesting a buffer effect provided by this cultivation system in the impact caused by the insecticide.

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Five candidate pheromone components were identified by analyzing pheromone gland extracts by gas chromatography (GC), coupled GC-electroantennographic detection (EAD), and coupled GC-mass spectrometry (MS) : (E)-11-hexadecenol(E11-16 : OH), (Z)-11-hexadecenol (Z11-16 : OH), (E)-11-hexadecenal, (E)-11-hexadecenyl acetate, and (Z)-3,(Z)-6,(Z)-9-tricosatriene (Z3,Z6,Z9-23 : Hy). In electroantennogram (EAG) recordings, synthetic E11-16 : OH elicited stronger antennal responses at low doses than other candidate pheromone components. Field tests demonstrated that synthetic E11-16 : OH as a trap bait was effective in attracting males, whereas addition of Z11-16 : OH inhibited the males' response. Z3,Z6,Z9-23 : Hy strongly enhanced attractiveness of E11-16 : OH, but was not attractive by itself. A pheromone blend with synergistic behavioral activity of an alcohol (E11-16 : OH) and hydrocarbon (Z3,Z6,Z9-23 : Hy) component is most unusual in the Lepidoptera. The synthetic two-component pheromone is approximately 60 times more attractive than the female-produced blend and might facilitate the control of this pest.

ABSTRACT:The fall armyworm (Spodoptera frugiperda) causes damage and reduction in maize production and is considered a pest difficult to control, thus determining its spatial distribution pattern contributes to the development of suitable sampling and control strategies. The aim of this study was to evaluate the spatial distribution of Spodoptera frugiperda in maize culture under the conditions of the wasteland of southern Pernambuco state. The experiment was conducted at the Experimental Station of Brejão -'Instituto Agronômico do Pernambuco' (IPA) from April to May 2012. The study area consisted of 100 plots of 60 m 2 , where 10 plants per plot were weekly sampled at random. In each plant, the number of small and large larvae of S. frugiperda was counted on the leaves and the husk of ears. According to the data observed, the aggregation indices (variance/mean ratio, Morisita's index, Green's Index, and Exponential k of a negative binomial distribution) indicated aggregate distribution for both small and large caterpillars, and the negative binomial distribution was the most appropriate model to represent the distribution pattern of small larvae of this pest in the field. In maize crop in the wasteland of southern Pernambuco state, S. frugiperda presents aggregate pattern of distribution and tends to spread from the points of aggregation and colonize form the border into the center of cultures. RESUMO: A lagarta-do-cartucho (Spodoptera frugiperda) causa danos e redução na produção de milho, e é considerada uma praga de difícil controle; portanto, a determinação do padrão de distribuição espacial contribui para a elaboração de amostragens adequadas e estratégias de controle. O objetivo deste trabalho foi avaliar o padrão de distribuição espacial de Spodoptera frugiperda na cultura do milho, nas condições do Agreste Meridional de Pernambuco. O experimento foi conduzido na Estação Experimental de Brejão-PE, do

Evaluation of Sexual Pheromone of Neoleucinodes elegantalis Guenée (Lepidoptera: Crambidae) ABSTRACT-Four synthetic components of the sexual pheromone identified from the small tomato borer Neoleucinodes elegantalis Guenée (BPT) were evaluated: (E)-11-hexadecenol (E11-16:OH), (Z)-11-hexadecenol (Z11-16:OH), (E)-11-hexadecenal (E11-16:Al) and (E)-11-hexadecenyl acetate (E11-16:OAc). Field tests were carried out with traps aiming at identifying the most effective component in the capture of N. elegantalis males, and determining the effect of different concentrations of the isomeric Z11-16:OH, in a mixture with the most effective component, in the capture of the males. In laboratory, electrophysiological tests were carried out with an electroantennograph to monitor the response of the antenna of N. elegantalis males to logarithmic concentrations of the four identified components. E11-16:OH, at the concentration of 100 µg, was the most effective among the tested components of the sexual pheromone of BPT. The isomer of this component, Z11-16:OH, was added and reduced insect capture. Physiological responses to all tested components were registered. E11-16:OH promoted depolarization of the antenna in straight relation with its concentration, while for the others components, the chemoreceptors have responded only to the higher concentrations.