Insect pests and natural enemies associated with lettuce Lactuca sativa L. (Asteraceae) in an aquaponics system.

Although food is produced in aquaponics systems worldwide, no information is available on the occurrence of insect pests and natural enemies in aquaponic lettuce, Lactuca sativa L. In this study, a survey was carried out in an aquaponic system combining lettuce with lambari, Astyanax altiparanae (Garutti & Briski), aiming to determine the insect pests and natural enemies associated with this system. We also determined the predominant insect species and the effect of meteorological factors on their populations. Insect abundance was estimated by visual sampling during 13 cultivation cycles, totaling 27 sampling dates. The meteorological factors considered were air temperature and relative humidity, and their effects were determined using the Pearson correlation. The thrips Frankliniella schultzei (Trybom) and Caliothrips phaseoli (Hood) and the aphid Aphis spiraecola (Patch) predominated. Ambient temperature and relative humidity were essential factors affecting C. phaseoli and F. schultzei. The natural enemies found on the lettuce plants were the thrips Franklinothrips vespiformis (Crawford) and Stomatothrips angustipennis (Hood) and the ladybugs Cycloneda sanguinea L., Eriopis connexa (Germar), and Hippodamia convergens (Guérin-Méneville). These results constitute the first step for a lettuce-integrated pest-management program in aquaponics systems.

Suitability of spider mites and green peach aphids as prey for Eriopis connexa (Germar) (Coleoptera: Coccinellidae).

The ladybird Eriopis connexa is an important natural enemy of several pest arthropods in agroecosystems. High population of this predator is frequently observed in strawberry and soybean crops associated with spider mites. We used two-sex life table parameters to evaluate under laboratory conditions, the suitability of three species of spider mites (Tetranychus evansi, Tetranychus urticae, Tetranychus ogmophallos), and a species of aphid (Myzus persicae) as a prey for the predator E. connexa. Eriopis connexa completed immature development on all prey species except on T. evansi, in which all individuals of predator died before reaching the pupal stage. Among prey species that allowed the immature development of E. connexa, T. urticae and M. persicae provided a faster development time to the predator. Oviposition days, longevity and fecundity of E. connexa on T. urticae and M. persicae were substantially longer/higher than on T. ogmophallos. Net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) of E. connexa feeding on T. urticae and M. persicae were also higher than those on T. ogmophallos. Based on the overall performance of the ladybird, the order of suitability of prey species was M. persicae > T. urticae > T. ogmophallos > T. evansi.

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)

Biological aspects of Aphis gossypii Glõver, 1877 (Hemiptera: Aphididae) on colored lint cotton cultivars / Aspectos biológicos de Aphis gossypii Glõver, 1877 (Hemiptera: Aphididae) em cultivares de algodoeiro com fibra colorida

This paper outlines the results of a study into the biological aspects of Aphis gossypii Glõver on colored cotton cultivars through the construction of life tables. In addition, we evaluate the influence of density of gossypol glands and trichomes of leaves on the biology of the aphid. Tests were conducted in a climate chamber at 25 ± 2C, with relative humidity (RH) at 70 ± 10%, and a photophase of 12 hours, using the cultivars BRS Rubi, BRS Safira, and BRS Verde. Newly hatched nymphs were individually isolated in petri dishes containing leaf discs of cotton cultivars on a layer of water-agar (1%) of approximately 5 mm thick. An evaluation of the trichomes and gossypol gland densities of the cotton leaf plants was performed under a stereomicroscope, delimited to an area of 1 cm², and a count and identification of those on the surface was made. The feed substrates that were evaluated influenced the nymphal stage of A. gossypii. BRS Verde provided the shortest duration and BRS Safira was the longest during this phase. The cultivar BRS Verde, with the lowest density of trichomes, provided a large number of nymphs and led to a higher net reproductive rate (R0). Given these results, conclusions can be drawn that the colored cotton cultivars influence the duration of nymphal and adult stages of A. gossypii. The cultivar with a high density of trichomes on leaves (BRS Safira) adverse [...]

Este trabalho teve por objetivos estudar aspectos biológicos de Aphis gossypii em cultivares de algodoeiro de fibra colorida, construir tabelas de vida e avaliar a influência da densidade de tricomas e glândulas de gossipol das folhas das plantas na biologia do pulgão. Os ensaios foram conduzidos em câmara climatizada regulada a 25 ± 2C, UR de 70 ± 10% e fotofase de 12 horas, utilizando-se as seguintes cultivares: BRS Rubi, BRS Safira e BRS Verde. Ninfas recém-nascidas foram isoladas individualmente em placas de Petri contendo discos foliares de algodoeiro das cultivares sobre uma lâmina de ágar-água (1%) de aproximadamente 5 mm. A avaliação da densidade de tricomas e de glândulas de gossipol das folhas das plantas foi realizada sob microscópio estereoscópico, delimitando-se uma área de 1 cm² e, em seguida, realizando-se a contagem e identificação dos mesmos nessa superfície. Os substratos alimentares avaliados influenciaram a fase ninfal de A. gossypii, sendo que a BRS Verde proporcionou menor tempo de duração e a BRS Safira, o maior período desta fase. A cultivar BRS Verde com a menor densidade de tricomas proporcionou elevada produção de ninfas e a maior taxa líquida de reprodução (R0). Diante dos resultados, conclui-se que as cultivares de algodoeiro colorido influenciam o tempo de duração da fase ninfal e adulta do pulgão A. gossypii. A cultivar com elevada densidade [...]

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.