Spatiotemporal analysis of distribution of pest and predator in corn crops

Crop pests have negative impacts on yield. This paper proposes a spatiotemporal geostatistical modeling to compare data of adult Syrphidae fly count and corn leaf aphid Rhopalosiphum maidis (Fitch, 1856) colonies in corn crops. The use of a geostatistical model that allows the space-time variation makes the approach more interesting because it is a more complete model. Multiple regression was used to model the trend component for the variable response adult Syrphidae fly count and corn leaf aphid colonies, with the coordinates serving as covariates and the spatiotemporal variations around the deviation are described by a random spacetime residual field. Finally, the prediction map obtained by kriging may be a biological indicator of possible corn leaf aphid colonies in the corn crop. It was possible to verify that the occurrence of the pest provided a significant increase in adult predators and seminatural habitats may favor populations of natural enemies.

Oil palm age and genotype interfere with defoliator lepidopteran infestation

The state of Pará has oil palm plantings of different ages and distinct genotypes. The understanding of which factors influence the occurrence and abundance of defoliating caterpillars in palm groves is paramount for control strategies based on integrated pest management (IPM). This study quantified the effect of oil palm age independently, and that of oil palm age and genotype, on the occurrence and abundance of defoliating caterpillars. Data were collected from 1994­2014 and consisted of counting the average number of caterpillars/leaf/parcel. For Opsiphanes invirae and Talima sp., leaf 17 was sampled; for Acharia spp., Euclea sp., Euprosterna elaeasa, Natada sp., and Automeris liberia, leaf 25 was sampled. For Oiketicus kirbyi, Antaeotricha sp., and Brassolis sophorae no specific leaf was considered. Palm trees were classified into three groups: young palm trees (0­8 years after planting), adult palm trees (9­19 years after planting), and old palm trees (over 20 years after planting). Talima sp. showed the highest population peak followed by O. invirae, Acharia spp., Elaeis elaeasa and Euclea sp. This study concludes that genotype has an impact on the infestation by defoliating caterpillars. Also, oil palms at reproductive age are more prone to higher infestation levels than young trees. While population levels of defoliating caterpillars are low in general, outbreaks are frequent. Importantly, intraspecific genotypes are more vulnerable than interspecific genotypes to infestations by defoliating caterpillars. This study contributes to the bioecological knowledge on defoliating caterpillars on oil palm and therefore provides important information to strengthen integrated pest management practices.

Phytophagous insects and natural enemies in kale under organic and chemical fertilizers / Insetos fitófagos e inimigos naturais em couve sob adubação orgânica e química

Organic agriculture is distinguished by practices that benefit the environment and support sustainable agriculture. In the present study, leafy kale, Brassica oleracea L. var. acephala DC., was submitted to chemical and organic (castor bean cake and bovine manure) fertilization treatments aiming to verify the influence of these fertilizers on the occurrence of insect pests and natural enemies. The insects were sampled by visual examination of plants and pitfall traps. Brevicoryne brassicae (L.) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) were the phytophagous insects that occurred more significantly in kale, under chemical rather than organic fertilization, whereas Harmonia axyridis (Pallas), Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae), Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae) and spiders (Arachnida: Araneae) were abundant in kale under organic fertilizer. The study showed that castor bean cake and bovine manure as leafy kale fertilizers can reduce the use of insecticides and provide quality food.(AU)

A agricultura orgânica destaca-se pelo emprego de práticas que beneficiam o meio ambiente e aumentam a sustentabilidade na agricultura. No presente estudo, a couve-de-folha, Brassica oleracea L. var. acephala DC., foi submetida a tratamentos de adubação química e orgânica à base de torta de mamona e esterco bovino para se verificar a influência dos fertilizantes na ocorrência de insetos pragas e inimigos naturais. Os insetos foram amostrados por meio de exame visual de plantas e armadilhas tipo alçapão. Brevicoryne brassicae (L.) e Myzus persicae (Sulzer) (Hemiptera: Aphididae) foram os insetos fitófagos que ocorreram significativamente em maior número em couve sob adubação química que orgânica, enquanto Harmonia axyridis (Pallas), Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae), Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae) e aranhas (Arachnida: Araneae) foram abundantes em couve sob adubo orgânico. O estudo evidenciou que o uso de torta de mamona e esterco bovino como adubo de couve-de-folha pode reduzir o uso de inseticidas e fornecer alimentos de qualidade.(AU)

Validation of the sampling methodology for Opsiphanes invirae caterpillars on oil palm plantations in the Brazilian Amazon / Validação da metodologia de amostragem para lagartas de Opsiphanes invirae em plantios de palma de óleo na Amazônia brasileira

ABSTRACT: This study validated the use of leaf 17 on the sampling of Opsiphanes invirae Hübner (Lepidoptera: Nymphalidae) through the quantification of caterpillar abundance on the different spirals leaves, in comparison to leaf 17, and, on the apical, intermediate and basal leaf regions. This study was performed in the state of Pará, between March-2014 and March-2015. Results confirmed that leaf 17 is the most adequate method for monitoring this defoliator pest.

RESUMO: Esta pesquisa validou a utilização da folha 17, nas amostragens de Opsiphanes invirae Hübner )Lepidoptera: Nymphalidae), através da quantificação da abundância de lagartas nas diferentes folhas que compõem os espirais em comparação com a folha 17, e, em diferentes regiões da folha (apical, intermediária e basal). O estudo foi realizado no Pará entre março de 2014 e março de 2015. Os resultados confirmam que a folha 17 é a mais adequada para ser utilizada no monitoramento desse desfolhador.

Análise de fauna e flutuação populacional de Carabidae e Staphylinidae (Coleoptera) em sistemas de plantio direto e convencional / Faunal analysis and population fluctuation of Carabidae and Staphylinidae (Coleoptera) in no-tillage and conventional tillage systems

O objetivo deste estudo foi analisar a fauna de carabídeos e estafilinídeos por meio de vários índices e obter a flutuação populacional das espécies dominantes em fragmento florestal e cultura de soja/milho sob sistemas de plantio direto e convencional. As amostragens dos coleópteros foram realizadas no período de novembro/2004 a abril/2007 em Guaíra, São Paulo, sendo quinzenal durante o período de safra e mensal nas entressafras. Para a obtenção das amostras utilizou-se armadilhas de solo distribuídas em dois transectos de 200 m de comprimento, sendo 100 m na cultura e 100 m no fragmento. A fauna foi caracterizada pelos índices de diversidade e equitabilidade e pela abundância. No sistema de plantio direto capturou-se maior número de espécies de carabídeos e estafilinídeos e os índices de equitabilidade e diversidade indicaram que a comunidade desses besouros mostrou-se melhor estruturada quando comparado com a observada no sistema de plantio convencional. Entre as espécies de carabídeos destacou-se Abaris basistriatus por ter se caracterizado como dominante na cultura e fragmento florestal das duas áreas experimentais. As espécies Scarites sp. 4 e A. basistriatus geralmente apresentaram picos populacionais quando a cultura de soja contava menos de 30 dias da implantação, as demais espécies apresentaram picos populacionais que ocorreram em períodos variados das safras. A precipitação pluvial foi o fator meteorológico que obteve a maioria dos coeficiente positivos em seguida o fator temperatura mínima.

The objective of this study was to analyze carabid and staphylinid fauna through several faunistic indexes and to obtain the population fluctuation of the dominant species in forest fragment and soybean-corn crop in no-tillage and conventional cropping system. The samplings of the coleopteran were carried out from November/2004 to April/2007, in Guaíra, São Paulo, being biweekly during the crop period and monthly in the off-season crop. For obtaining the samples it was used pitfall traps, distributed in two transects of 200 m long being 100 m in the culture and 100 m in the fragment. The fauna was characterized by indexes of diversity, equitability, and abundance. In no-tillage system the larger number of carabid and staphylinid species and the equitability and diversity indexes indicated that the community of those beetles shows a better structure when compared with the conventional cropping system. Among the carabid species Abaris basistriatus stood out for having been characterized as dominant in crop and forest fragment of the two experimental areas. The species Scarites sp. 4 and A. basistriatus generally presented population peaks when the crop soybean counted less than 30 days of the implantation, the other species presented population peaks that were observed in varied times of the crops. Pluvial precipitation was the meteorological variable that obtained the largest number of positive correlations followed by minimum temperature.