-The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4', 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD 50 from 2.72 to 39.71 mg g -1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis.Index terms: natural insecticide, pest management, alternative control, secondary metabolites. Compostos de plantas com atividade inseticida a coleópteros-praga de produtos armazenadosResumo -O objetivo deste trabalho foi selecionar plantas com atividade inseticida, para isolar, identificar e avaliar a bioatividade de compostos inseticidas presentes nessas plantas, contra as seguintes pragas de produtos armazenados da ordem Coleoptera: Sitophilus zeamais Mots. (Curculionidae), Rhyzopertha dominica F. (Bostrichidae) e Oryzaephilus surinamensis L. (Silvanidae). As espécies de plantas usadas foram: anis (Ocimum selloi Benth), arruda (Ruta graveolens L.), cordão-de-frade (Leonotis nepetifolia L.), datura (Datura stramonium L.), erva baleeira (Cordia verbenacea L.), hortelã (Mentha piperita L.), melão-de-são-caetano (Mormodica charantia L.) e mentrasto (Ageratum conyzoides L.). Avaliou-se a toxicidade dos extratos hexânico e etanólico dessas plantas sobre R. dominica. Somente o extrato hexânico de A. conyzoides apresentou atividade inseticida. O extrato hexânico desta planta foi fracionado, sucessivamente, por cromatografia de coluna de sílica gel, para isolamento e purificação dos compostos ativos. Os compostos 5,6,7,8,3',4', 5,6,7,8,5'-metilenodioxiflavona e cumarina foram identificados. Entretanto, somente a cumarina apresentou atividade inseticida às três espécies de insetos (DL 50 de 2,72 a 39,71 mg g -1 de i.a.). A ordem crescente de suscetibilidade à cumarina foi R. dominica, S. zeamais e O. surinamensis.Termos para indexação: inseticida natural, manejo de pragas, controle alternativo, metabolito secundário.

This work aimed at identifying plant compounds with insecticidal activity against Diaphania hyalinata (L.) (Lepidoptera: Pyralidae), Musca domestica (L.) (Diptera: Muscidae), Periplaneta americana (L.) (Blattodea: Blattidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetaefolia L.), Jimson weed (Datura stramonium L.), 'baleeira' herb (Cordia verbenaceae L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.) and billy goat weed (Ageratum conyzoides L.). Firstly, the insecticidal activities of hexane and ethanol plant extracts were evaluated against adults of R. dominica. Among them, only the hexane extract of A. conyzoides showed insecticidal activity. The hexane extract of this plant species was therefore fractionated by silica gel column chromatography to isolate and purify its bioactive chemical constituents. Three compounds were identified using IR spectra, (1)H NMR, (13)C NMR, HMBC and NOE after gel chromatography: 5,6,7,8,3', 4', 5'-heptamethoxyflavone, 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone and coumarin. The complete assignment of (13)C NMR to 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone was successfully made for the first time. 5,6,7,8,3'-Pentamethoxy-4', 5'-methylenedioxyflavone did not show any insecticidal activity against the four insect species tested. 5,6,7,8,3', 4', 5'-Heptamethoxyflavone showed low activity against D. hyalinata and R. dominica and was not toxic to M. domestica or P. americana. In contrast, coumarin showed insecticidal activity against all four insect pest species tested, with the following order of susceptibility: R. dominica < P. americana < D. hyalinata < M. domestica after 24 h exposure.

Bemisia tabaci, Brevicoryne brassicae and Thrips tabaci on Brassica oleracea 197Bemisia tabaci, Brevicoryne brassicae and Thrips tabaci abundance on Brassica oleracea var. acephalaGermano Leão Demolin Leite (1) , Marcelo Picanço (2) , Gulab Newandram Jham (3) and Márcio Dionízio Moreira Abstract -Kale Brassica oleracea var. acephala is attacked by whitefly Bemisia tabaci, aphid Brevicoryne brassicae and Thrips tabaci. One of the main reasons for extensive insecticide application is the lack of information about factors that control insect population. The objectives of this study were to investigate the relationships between predators and parasitoids, organic compound leaves, levels of leaf nitrogen and potassium, total rainfall, relative humidity, sunlight and median temperature on the abundance of whitefly, aphid, and thrips in kale genotype "Talo Roxo". The beating tray method, direct counting and magnifying lens were used to estimate the number of these pests, predators and parasitoids. Median temperature, sunlight and relative humidity correlated to the amount of leaf nonacosane, which in turn was associated with aphids population increase. A tendency in the reduction of aphids and thrips populations with increase in total rainfall was observed. The whitefly can be a harmful pest in kale producing regions of higher temperature and smaller rainfall. In regions which present moderate temperature, where there is a high incidence of aphids, genotype with low leaf wax content should be chosen. Natural enemies, especially the parasitoid Adialytus spp., can control agents of the aphids population in kale. Index terms: population dynamics, nonacosane, climatic factors, Braconidae. Abundância de Bemisia tabaci, Brevicoryne brassicae e Thrips tabaci em Brassica oleracea var. acephalaResumo -A couve, Brassica oleracea var. acephala, é atacada por mosca-branca Bemisia tabaci, pulgão Brevicoryne brassicae e tripes Thrips tabaci. Uma das principais razões para o uso intensivo de inseticidas é a falta de informação sobre os fatores que controlam a população de insetos. O objetivo deste estudo foi investigar as relações entre predadores e parasitóides, compostos orgânicos foliares, níveis foliares de nitrogênio e de potássio, pluviosidade total, umidade relativa, insolação e temperatura média na abundância da mosca-branca, pulgões e tripes em couve genótipo Talo Roxo. Foi usado o método da batida em bandeja, contagem direta e lupas de aumento para estimar o número dessas pragas, de predadores e de parasitóides. A temperatura média, insolação e umidade relativa correlacionaram com nonacosano foliar que, por sua vez, esteve associado com o aumento populacional de pulgões. Foi observada uma tendência na redução de pulgões e de tripes com o aumento da pluviosidade total. A mosca-branca pode ser uma praga prejudicial em regiões produtoras de couve de maior temperatura e de menor pluviosidade. Em regiões onde se tem maior incidência de pulgões (regiões de temperatura moderada) deve-se escolher um genótipo com baixo conte...

No abstract

The objective of this work was to study the e}ect of plant canopy height on the resistance of the tomato species Lycopersicon hirsutum to the tomato leafminer Tuta absoluta[ Determination of the levels of tridecan!1!one "1!TD# and undecan!1!one "1!UD# in L[ hirsutum\ as well as the leaf area\ density and types of trichomes present in L[ hirsutum and L[ esculentum were made on apical\ medium and basal parts of plant canopy[ Correlation of these data were made with the following biological characteristics of T[ absoluta] rates of oviposition and egg hatching^length of egg\ larval and pupal stages^mortality of the larval and pupal stages^pupal weight^and sex ratio[ Levels of 1!TD on leaves of L[ hirsutum increased from bottom to top of canopy[ Tuta absoluta had higher oviposition and egg hatching\ as well as lower mortalities and smaller larval and pupal periods in L[ esculentum than in L[ hirsutum[ Longer pupal period and greater number of small and large mines of T[ absoluta were veri_ed in the apical and medium parts of L[ hirsutum plants[ On the other hand\ higher pupal mortality and longer larval periods were obtained in the apical and basal parts of the L[ hirsutum plants[ Larval mortality was higher in the basal part of those plants[ In L[ esculentum\ leaves from the apical part of the plant promoted lower mortality\ longer larval period and greater number of large mines of T[ absoluta[ However\ a shorter pupal period was veri_ed on leaves of the basal part[ It appears that an increase in glandular trichome density in L[ hirsutum leads to an increase in the levels of 1!TD\ which\ in turn slows down larval development[