Lethal and Sublethal Effects of Annona spp. Derivatives on Bemisia tabaci MEAM 1 (Hemiptera: Aleyrodidae) in Tomato.

The whitefly Bemisia tabaci(Gennadius) MEAM 1 is one of the main insect species that colonize tomato plants and cause direct and indirect damage. The use of botanical derivatives may be a valuable method of insect control to reduce the inappropriate use of synthetic insecticides on crops. In this study, we evaluated the bioactivity of ethanolic extracts prepared from Annonaceae species compared to that of the commercial insecticides based on acetogenins (Anosom® 1 EC, anonine 10,000 mg L-1) and thiamethoxam (Actara® 250 WG) on eggs, nymphs, and adults of the whitefly in tomato. Initially, the effects of the ethanolic seed extracts of Annona mucosa (Jacq.), Annona muricata L., and Annona sylvatica A.St.-Hil on adult insect behavior were evaluated. The rates of infestation and oviposition deterrence indicated the inhibitory effects of the extract of A. muricata (500 mg L-1). Then, the possible systemic effects of the extracts were evaluated; however, no effects on nymphal development or insect viability were observed. The LC50 and LC90 of the ethanolic extract of A. mucosa seeds at 500 mg L-1 (10.83 and 200.24 mg L-1, respectively) were estimated and were used in ovicidal tests and compared to positive (Actara® 250 WG and Anosom® 1 EC), and negative controls (water: acetone, 1:1 v/v). At LC90, fewer eggs (35.00%) had hatched at 13 days after application than in the other treatments. The results of this study demonstrate the potential use of botanical derivatives of Annona spp. for the management of B. tabaci MEAM 1 in tomato.

BIOACTIVITY OF EXTRACTS FROM SOLANACEAE AGAINST Zabrotes subfasciatus / Bioactividad de extractos de Solanaceae contra Zabrotes subfasciatus

ABSTRACT The botanical family Solanaceae has many species producing compounds with insecticidal properties, e.g. nicotine and capsaicin, which are used for pest management in agriculture. This fact provides perspectives to identify insecticidal compounds in Brazilian native species of Solanaceae. In this study, we performed a screening with 25 ethanolic extracts from 17 Solanaceae species in order to evaluate their bioactivity against the Mexican bean weevil, Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae). The bioactivity of Solanaceae ethanolic extracts (2,500 mg kg-1) was tested with residual contact bioassays. Adults of Z. subfasciatus were exposed to treated bean grains, and adult mortality, oviposition, F1 progeny and damages on grains were quantified. Most of the ethanolic extracts from Solanaceae reduced the number of eggs per sample, the egg-adult viability, the F1 progeny and the damages on bean grains promoted by Z. subfasciatus, but none of them interfered on its sex ratio. Ethanolic extract from leaves of Solanum lycocarpum A. St.-Hil promoted the most promissory effects on Z. subfasciatus. This ethanolic extracts can be a suitable alternative to control Z. subfasciatus in stored beans, mainly for small farmers and organic farmers.

RESUMEN La familia botánica Solanaceae tiene muchas especies que producen compuestos con propiedades insecticidas, e.g. nicotina y capsaicina, que se utilizan para el control de plagas en la agricultura. Este hecho proporciona perspectivas promisorias para identificar compuestos insecticidas en especies nativas brasileñas de Solanaceae. En el presente estudio se llevó a cabo un cribado con 25 extractos etanólicos de 17 especies de Solanaceae con el propósito de evaluar su bioactividad sobre el gorgojo pinto del frijol, Zabrotes subfasciatus (Coleoptera: Chrysomelidae: Bruchinae). La bioactividad de los extractos etanólicos se evaluó por experimentos de contacto residual. Los adultos de Z. subfasciatus se expusieron a los frijoles tratados con los extractos y se midió la mortalidad de los adultos, la ovoposición, la progenie F1 y el daño en los granos. La mayoría de los extractos etanólicos redujeron el número de huevos, la viabilidad de los huevos, la progenie y el daño en los granos, pero ninguno de ellos interfirió en la proporción sexual de los insectos. El extracto etanólico de las hojas de Solanum lycocarpum A. St.-Hil promovió los efectos más prometedores sobre Z. subfasciatus. Este extracto puede ayudar a controlar a Z. subfasciatus en frijoles almacenados, principalmente a los pequeños agricultores y a los agricultores orgánicos.

Avocado kernels, an industrial residue: a source of compounds with insecticidal activity against silverleaf whitefly.

Fruit processing waste, such as kernels (endocarp + seed) of avocado [Persea americana Mill. (Lauraceae)], could be used as raw material in the preparation of botanical insecticides. In light of this potential, this study assessed the insecticidal action of extracts and fractions from kernels of two avocado cultivars (Breda and Margarida) on Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B, an important pest species in tropical conditions. Ethanolic and aqueous extracts prepared from kernels of P. americana, regardless of the plant cultivar used, caused promising insecticidal activity to whitefly nymphs. Based on yield in crude extracts [10.32 and 9.85% (w/w), respectively, for cultivars Breda and Margarida], on the bioassay results with crude extracts and on the chemical profiles, the ethanolic extract of kernels of P. americana cv. Breda was chose for the continuation of the study. Thus, the ethanolic extract of kernels of cv. Breda (LC50 = 197.84 ppm and LC90 = 567.19 ppm) was selected and subjected to fractionation by the liquid-liquid partition technique. The hexane and dichloromethane fractions of this extract caused significant mortality of nymphs. The analysis using the ultraviolet (UV) and hydrogen nuclear magnetic resonance (1H NMR) showed the presence of long-chain aliphatic compounds (alkanols or acetogenins of Lauraceae), alkylfurans (or avocadofurans), and unsaturated fatty acids in these fractions, which are possibly related to bioactivity observed in B. tabaci, besides saccharides. The results show that kernels of P. americana are promising sources of compounds with insecticidal action for the control of B. tabaci biotype B, a great opportunity to transform environmental problems into eco-friendly solutions to agriculture.

Isolation of Chavibetol and Methyleugenol from Essential Oil of Pimenta pseudocaryophyllus by High Performance Liquid Chromatography.

A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of P. pseudocaryophyllus leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID. Chavibetol was isolated with high purity (98.7%) and mass recovery (94.6%). The mass recovery (86.4%) and purity (85.3%) of methyleugenol were lower than those of chavibetol. Both compounds were identified on the basis of spectral analysis. The results suggest that the method can provide chavibetol with high purity, mass recovery, and productivity from crude essential, which will be used in bioassays against stored insect pests.

Selectivity of plant extracts for Trichogramma pretiosum Riley (Hym.: Trichogrammatidae).

We evaluated the selectivity of three plant extracts with potential insecticidal effects for the parasitoid Trichogramma pretiosum Riley, which is commonly used in biological pest control. The plant extracts assayed were an acetone extract of Toona ciliata M. Roem., commercial neem oil, and a nanoencapsulated formulation of neem oil (NC40). The toxicity of the plant extracts to T. pretiosum was evaluated according to the recommendations of the International Organization for Biological Control- IOBC Working Group. We assessed the susceptibility of adults of the maternal and F1 generations and immature stages of T. pretiosum to the extracts. Females exposed to egg cards treated with commercial neem oil parasitized almost 70% fewer eggs than control eggs treated with water; and this extract was therefore classified as slightly harmful. When the eggs were offered to females 24h after treatment with neem oil and aqueous NC40, the parasitism rate also decreased, and the two extracts were classified as slightly harmful. Adult emergence was lower for parasitoids that fed on host eggs offered 24h after the treatment with the T. ciliata extract, which was considered slightly harmful. The emergence of T. pretiosum from eggs, larvae and pupae treated with the different plant extracts, did not decrease compared to development stages treated with the water control. The use of T. pretiosum, combined with the application of an ethanol extract of T. ciliata and a nanoencapsulated formulation of neem, appears to be feasible in view of these low toxicity indices.

Searching for promising sources of grain protectors in extracts from neotropical annonaceae / Búsqueda de fuentes prometedoras de protectores de granos en extractos de anonaceas neotropicales

To investigate potential sources of novel grain protector compounds against Sitophilus zeamais (Coleoptera: Curculionidae), which is an important insect pest of stored cereals, this study evaluated the bioactivity of ethanolic extracts (66) prepared from 29 species belonging to 11 different genera of Neotropical Annonaceae. A screening assay demonstrated that the most pronounced bioactive effects on S. zeamais were caused by ethanolic extracts from Annona montana, A. mucosa, A. muricata, and A. sylvatica seeds, causing the death of all weevils exposed, almost complete inhibition of the F1 progeny and a drastic reduction in grain losses. Furthermore, the ethanolic extracts obtained from the leaves of A. montana, A. mucosa, A. muricata, and Duguetia lanceolata, especially A. montana and A. mucosa, demonstrated significant bioactive effects on the studied variables; however, the activity levels were less pronounced than in the seed extracts, and the response was dependent on the concentration used. This study is the first to report the activity of secondary metabolites from D. lanceolata on insects as well as the action of A. sylvatica on pests associated with stored grains.

Para investigar las posibles fuentes de nuevos compuestos protectores de granos contra Sitophilus zeamais (Coleoptera: Curculionidae), una importante plaga de los cereales almacenados, este estudio evaluó la bioactividad de los extractos etanólicos (66) preparados a partir de 29 especies pertenecientes a 11 géneros distintos de Anonaceas Neotropicales. Un ensayo de selección demostró que los efectos bioactivos más relevantes sobre S. zeamais fueron causados por los extractos etanólicos de las semillas de Annona montana, de A. mucosa, de A. muricata y de A. sylvatica, que causaron la muerte de todos los gorgojos expuestos, la inhibición parcial de la progenie F1 y una drástica reducción de las pérdidas de grano. Además, los extractos etanólicos obtenidos de las hojas de A. montana, de A. mucosa, de A. muricata y de Duguetia lanceolata, especialmente de A. montana y de A. mucosa, demostraron efectos bioactivos significativos sobre las variables estudiadas. Sin embargo, los niveles de bioactividad fueron menores en comparación con los extractos de semillas, y la respuesta fue dependiente de la concentración utilizada. Este estudio es el primer relato sobre la actividad de los metabolitos secundarios de D. lanceolata sobre insectos, así como la acción de A. sylvatica sobre plagas asociadas a los granos almacenados.

Biologia de Mahanarva fimbriolata em gramíneas forrageiras / Biology of Mahanarva fimbriolata on forage grasses

Estudou-se a biologia de Mahanarva fimbriolata nas gramíneas Setaria anceps cv. 'Kazungula', Brachiaria brizantha cv. 'Marandu', ecótipos BB 33, BB 39, seleções IAC-BBS 5 e IAC-BBS 8, e cana-de-açúcar. 'SP-80-1842' (testemunha) em laboratório, visando a avaliar a resistência desses genótipos a essa praga. Os parâmetros avaliados foram: mortalidade e duração da fase de ninfa, razão sexual, período de pré-oviposição, número de ovos por fêmea, longevidade, duração e viabilidade da fase embrionária. Constatou-se maior mortalidade e prolongamento na fase de ninfa em IAC-BBS 8, B. brizantha cv. 'Marandu' e S. anceps cv. 'Kazungula'. Os menores valores de longevidade e fecundidade foram verificados em IAC-BBS 8 e IAC-BBS 5 e os maiores em cana-de-açúcar. A menor viabilidade da fase embrionária foi obtida em IAC-BBS 5 e a maior em IAC-BBS 8. Segundo os resultados da tabela de vida, a taxa líquida de reprodução (Ro) e a taxa finita de crescimento (λ) foram menores em IAC-BBS 8. Concluiu-se que IAC-BBS 8 é o genótipo mais resistente a M. fimbriolata, sendo a resistência do tipo antibiose e/ou não-preferência para alimentação.

Under controlled conditions, six forage grasses (Setaria anceps cv. 'Kazungula' and Brachiaria brizantha cv. 'Marandu'; and codified genotypes BB33, BB39; BBS 5 and BBS8), along with a control check (sugarcane cv. 'SP80-1842') were evaluated as to Mahanarva fimbriolata resistance. The following parameters have been evaluated: nymphal phase duration and mortality, sex ratio, pre-oviposition period, number of eggs per female, longevity, viability and embryonic period. The highest mortalities and longer nymphal periods occurred on BBS 8, cv. 'Marandu' and cv. 'Kazungula'. BBS5 also caused high nymph mortality, however with the shortest nymphal period. The lowest longevity and fecundity values were detected for BBS5 and BBS8, whereas the sugarcane control check revealed the highest one. As to embryonic phase viability, BBS 8 originated the highest values and BBS 5, the lowest ones. Among the tested plants, BBS 8 along with the cv. 'Marandu', proved to be the most resistant genetic material, both through antibiosis and/or nonpreference for feeding mechanism.

Comparative toxicity of an acetogenin-based extract and commercial pesticides against citrus red mite.

Acetogenins, a class of natural compounds produced by some Annonaceae species, are potent inhibitors of mitochondrial electron transport systems. Although the cellular respiration processes are an important biochemical site for the acaricidal action of compounds, few studies have been performed to assess the bioactivity of acetogenin-based biopesticides on spider mites, mainly against species that occur in orchards. Using residual contact bioassays, this study aimed to evaluate the bioactivity of an ethanolic extract from Annona mucosa seeds (ESAM) (Annonaceae) against the citrus red mite Panonychus citri (McGregor) (Acari: Tetranychidae), an important pest of the Brazilian citriculture. ESAM is a homemade biopesticide which was previously characterized by its high concentration of acetogenins. It caused both high mortality of P. citri females (LC50 = 7,295, 4,662, 3,463, and 2,608 mg l(-1), after 48, 72, 96, and 120 h of exposure, respectively) and significant oviposition deterrence (EC50 = 3.194,80 mg l(-1)). However, there was no effect on P. citri female fertility (hatching rate). In addition, the ESAM efficacy (in terms of its LC90) was compared with commercial acaricides/insecticides (at its recommended rate) of both natural [Anosom(®) 1 EC (annonin), Derisom(®) 2 EC (karanjin), and Azamax(®) 1.2 EC (azadirachtin + 3-tigloylazadirachtol)] and synthetic origin [Envidor(®) 24 SC (spirodiclofen)]. Based on all of the analyzed variables, the ESAM exhibited levels of activity superior to other botanical commercial acaricides and similar to spirodiclofen. Thus, our results indicate that ESAM may constitute a biorational acaricide for citrus red mite integrated pest management in Brazilian citrus orchards, particularly for local use.

Bioatividade de nanoformulações de nim sobre a traça-do-tomateiro / Bioactivity of neem nanoformulations on tomato pinworm

O uso de plantas inseticidas é uma importante ferramenta para o manejo de insetos-praga. Visando ao controle de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), nanoformulações de nim foram avaliadas. Após a estimativa de uma CL50 para uma formulação de óleo comercial de nim, bioensaios de seleção foram realizados com 22 nanoformulações. Para isso, lagartas neonatas foram alimentadas sobre folíolos tratados com soluções das nanoformulações durante 10 dias. Com as duas nanoformulações mais promissoras, NC40 aquoso e NC40 pó (NC 40=nanocápsulas de Poli- β-hidroxibutirato), foi avaliado o efeito sobre o desenvolvimento e a longevidade do inseto. A CL50 para o óleo de nim foi estimada em 0,20% ou 1,31mgL-1 de azadiractina. As nanoformulações NC40 aquoso e NC40 pó afetaram o desenvolvimento do inseto.

The use of insecticide plants is an important tool in the management of insect pests. Aiming to control Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), neem nanoformulations were evaluated. After estimating the LC50 for a commercial neem oil formulation, selection bioassays were performed with 22 nanoformulations. In order to do that, newly emerged caterpillars were fed on leaflets treated with nanoformulation solutions for 10 days. The effect on the development and longevity of the insect was evaluated with the two most promising nanoformulations, aqueous NC40 and powdered NC40 (NC 40 = Poly-β-hydroxibutirate nanocapsules). The LC50 for neem oil was estimated in 0.20% or 1.31mgL-1 of azadiractin. The nanoformulations aqueous NC40 and powdered NC40 affected the insect development.

Bioactivity of aqueous extracts of Clibadium sylvestre (Aubl.) Baill. and Derris amazonica Killip on the aphid Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) / Bioatividade de extratos aquosos de Clibadium sylvestre (Aubl.) Baill. e Derris amazonica Killip no controle do pulgão Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Studies with botanical insecticides have become more popular as an alternative to Integrated Pest Management. The purpose of this study was to evaluate the effect of leaf and fruit aqueous extracts, from the species Clibadium sylvestre, and leaves and root of Derris amazonica species at concentrations of 0, 1, 2, 4 and 8 percent, in the control of the aphid Myzus persicae (Hemiptera: Aphididae). Four experiments were conducted; two tests with choice preference and two tests with no choice preference, giving nine treatments and five repetitions. Phytochemical screening was carried out from the leaves and fruit of the species C. sylvestre and leaves and root of D. amazonica. Evaluations of mortality, number of nymphs, and deterrence index of the insects were conducted 24, 48 and 72 h after the application of the extracts. The aqueous extracts tested from C. sylvestre fruit concentrations had the highest mortality compared to the control; in the analysis of the number of the nymphs, the aqueous extract from fruit at 8 percent concentration had a higher efficiency than the other treatments. The D. amazonica leaves extract at 1 percent concentration showed the highest mortality and the lowest number of nymphs. The D. amazonica root extracts increased mortality at all concentrations tested, and the 8 percent concentration had the fewest nymphs. All treatments showed a deterrent effect. The 72 h period showed the greatest effect of the extracts, on two species of insects.

Estudos com inseticidas botânicos vêm ganhando espaço como alternativa no Manejo Integrado de Pragas. Conduziu-se este trabalho com o objetivo de avaliar o efeito de extratos aquosos de folhas e frutos da espécie Clibadium sylvestre, e folhas e raízes da espécie Derris amazonica nas concentrações 0, 1, 2, 4 e 8 por cento, no controle do pulgão Myzus persicae (Hemiptera: Aphididae). Foram conduzidos quatro ensaios, dois testes de preferência sem chance de escolha e dois testes de preferência com chance de escolha, totalizando nove tratamentos com cinco repetições. Foi realizada a triagem fitoquímica das folhas e dos frutos da espécie C. sylvestre e das folhas e das raízes de D. amazonica. As avaliações de mortalidade, número de ninfas e índice de deterrência dos insetos, foram realizadas 24, 48 e 72 horas após a aplicação dos extratos. Os extratos aquosos do fruto do C. sylvestre nas concentrações testadas apresentaram maior mortalidade frente à testemunha, na análise do número de ninfas, o extrato aquoso do fruto do C. sylvestre a 8 por cento apresentou maior eficiência que os demais tratamentos. O extrato da folha de D. amazonica na concentração 1 por cento apresentou maior mortalidade e menor número de ninfas que os demais tratamentos. Os extratos da raiz de D. amazonica aumentaram a mortalidade em todas as concentrações testadas e a concentração 8 por cento da raiz de D. amazonica, apresentou menor número de ninfas. Todos os tratamentos testados apresentaram efeito deterrente. O período de 72 horas foi o que apresentou maior efeito dos extratos, das duas espécies estudadas sobre os insetos.

Brassinosteroids interact negatively with jasmonates in the formation of anti-herbivory traits in tomato.

Given the susceptibility of tomato plants to pests, the aim of the present study was to understand how hormones are involved in the formation of tomato natural defences against insect herbivory. Tomato hormone mutants, previously introgressed into the same genetic background of reference, were screened for alterations in trichome densities and allelochemical content. Ethylene, gibberellin, and auxin mutants indirectly showed alteration in trichome density, through effects on epidermal cell area. However, brassinosteroids (BRs) and jasmonates (JAs) directly affected trichome density and allelochemical content, and in an opposite fashion. The BR-deficient mutant dpy showed enhanced pubescence, zingiberene biosynthesis, and proteinase inhibitor expression; the opposite was observed for the JA-insensitive jai1-1 mutant. The dpy x jai1-1 double mutant showed that jai1-1 is epistatic to dpy, indicating that BR acts upstream of the JA signalling pathway. Herbivory tests with the poliphagous insect Spodoptera frugiperda and the tomato pest Tuta absoluta clearly confirmed the importance of the JA-BR interaction in defence against herbivory. The study underscores the importance of hormonal interactions on relevant agricultural traits and raises a novel biological mechanism in tomato that may differ from the BR and JA interaction already suggested for Arabidopsis.

Effect of the aqueous extracts of the seeds of Talisia esculenta and Sapindus saponaria on fall armyworm

The effect of aqueous extracts of Talisia esculenta (T.E.) and Sapindus saponaria (S.S.), were evaluated on the development and mortality of 8-14th day-life Spodoptera frugiperda, an important pest of maize. Corn leaves were dipped in the aqueous extracts (1 percent w/v) and offered as food to the caterpillars. The treated corn leaves with the extracts caused larval mortality (26.71 percent/T.E.; 63.3 percent/S.S.) and also showed effect on the larval weight (237.50 mg/T.E.; 86.65 mg/S.S.) when compared with the control (11.3 percent and 293.45 mg), mortality and larval weight, respectively. The electrophoresis with gelatin (0.1 percent) showed two very clear white areas (trypsin activity) in the caterpillars midgut of all the treatments. Only the caterpillar treated with S. saponaria presented significant differences, showing trypsin activity (10.59 percent). Sapindus saponaria appeared better than Talisia esculenta and showed good potential to be used as control agent for S. frugiperda.

Este estudo procurou avaliar o potencial inseticida dos extratos aquosos de sementes de Talisia esculenta (St. Hil.) Radlk (Pitombal) e Sapindus saponaria L. (Saboneteira), ambas da família Sapindaceae, sobre Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), importante praga da lavoura de milho. As folhas de milho foram imersas nos tratamentos com extratos aquosos (1 por cento p/v) e oferecidas como alimento para as lagartas. Os resultados do período larval tais como mortalidade e peso médio foram respectivamente: para S. saponaria 63,15 por cento, 86,65 mg; para T. esculenta 26,71 por cento, 237,50 mg e para o controle 11,3 por cento, 293,45 mg. A eletroforese com gelatina 0,1 por cento mostrou duas regiões brancas muito nítidas (atividade tríptica) no intestino médio das lagartas de todos os tratamentos. Somente as lagartas do tratamento S. saponaria, apresentaram diferenças significativas, com uma atividade tríptica 10,59 por cento menor.

Não-preferência do ácaro-vermelho, Oligonychus yothersi McGregor(Acari: Tetranychidae), para oviposição em folhas de progênies deerva-mate (Ilex paraguariensis) / Non-preference of the red mite Oligonychus yothersi McGregor(Acari: Tetranychidae) for oviposition on leaves of Paraguay teaprogenies (Ilex paraguariensis)

A preferência para oviposição do ácaro-vermelho, Oligonychus yothersi McGregor, foi avaliada emcondições de laboratório em 52 progênies de erva-mate e uma testemunha coletada em uma propriedadeda região. Os experimentos foram realizados em discos foliares de erva-mate (2 cm de diâmetro), infestadoscom uma fêmea adulta do ácaro, e incubados a 25±1ºC e 14h de fotofase, durante cinco dias. As avaliaçõesforam realizadas diariamente, contando-se o número de ovos depositados no período, número de fêmeas quefugiram nas primeiras 48 horas e número de ovos depositados antes da fuga. Verificou-se que houvediscriminação do ácaro em dois grupos de progênies, em relação ao número de ovos, um que diferiu em relaçãoà testemunha (53,8% de progênies) e outro que se igualou à mesma (46,2% das progênies). No primeiro grupo,houve menor oviposição em 60,7% das progênies, enquanto que em cerca de 39,3% ocorreu maior oviposição(média de 3,1 ovos/fêmea). Em 57,7% das progênies houve fuga das fêmeas (10 a 40%), sendo que em 10dessas progênies não ocorreu oviposição antes da fuga. Os dados indicam que em algumas das progênies deerva-mate testadas há resistência por não-preferência para oviposição ao ácaro-vermelho.

The ovipositionpreference of the red mite Oligonychus yothersi McGregor was evaluated under laboratoryin 52 Paraguay tea progenies and one control collected in a local farm. The experiments were conductedon Paraguay tea leaf discs infested with one adult female mite/disc, incubated in a climate chamber(25±1ºC, 14h photophase) for five days. Evaluations were performed daily, by counting the number ofeggs laid in the period, the number of female escapes in the first 48 hours, as well as the number of eggslaid before the escaping. It was verified that discrimination by the mite occurred on two groups ofprogenies, in relation to the number of eggs: one group was different from the control (53.8% of the progenies) and the other was identical to it (46.2% of the progenies). In the first group, 60.7% ofprogenies were less oviposited while a higher number of eggs/female than the control was verified in39.3% of them. In 57.7% of progenies there was escape of some mites (10 to 40%), and in 10 of theseprogenies no eggs were laid. The data provide evidences that in some of the progenies evaluated thereis resistance by non-preference to oviposition of the Paraguay tea red mite

Bioatividade do extrato aquoso de sementes de nim sobre Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) em três formas de aplicação / Bioactivity of aqueous neem seeds extract on the Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) in three ways of application

No presente trabalho, avaliaram-se as atividades translaminar, sistêmica e de contato do extrato aquoso de sementes de Azadirachta indica A. Juss. (nim) sobre a traça-do-tomateiro Tuta absoluta (Meyrick). Foram realizados três experimentos envolvendo extratos aquosos de sementes de nim em concentrações de 0,5; 1,0; 5,0 e 10,0 g por 100 mL de água. Esses extratos foram aplicados no solo, na superfície adaxial de folíolos de tomateiro e diretamente sobre as lagartas. Quando os extratos foram aplicados no solo, em vasos contendo plantas de tomate, houve mortalidade de 48,3 a 100,0 por cento das lagartas, indicando que foram absorvidos e translocados na planta. Também ocorreu mortalidade larval de 57,0 a 100,0 por cento quando os extratos foram aplicados na superfície adaxial do folíolo, evidenciando o efeito translaminar. Quando foi aplicado diretamente sobre lagartas com seis dias de idade, observou-se mortalidade de 52,4 a 95,4 por cento, demonstrando a ação de contato do composto e seu potencial para controle da traça-do-tomateiro.

This work, aimed to study the translaminar, systemic and contact action of aqueous neem seeds extracts on the tomato leafminer Tuta absoluta (Meyrick). Three experiments with aqueous neem seeds extracts at concentrations of 0.5; 1.0; 5.0 and 10.0g/100 mL of water were conducted. These extracts were applied in the soil, in adaxial surface of the tomato plant foliole and directly over the insect. When the extracts were applied in the soil of pots containing tomato plants, the larval mortality rate was 48.3 percent to 100.0 percent, indicating that the extracts were absorbed and transferred inside the plant. There was also a larval mortality of 57.0 percent to 100.0 percent when the extracts were applied over the foliole adaxial surface, which shows the translaminar action. When the extracts were applied directly over larvae six days old, the larval mortality rate was 52.4 percent to 95.4 percent, which shows the action of contact of the extracts and its potential to control the tomato leafminer.

Associação entre teor de nitrogênio em cultivares de arroz e ataque de Oryzophagus oryzae (Costa Lima) (Coleoptera: Curculionidae) / Association between nitrogen content in rice cultivars and the damage of Oryzophagus oryzae (Costa Lima) (Coleoptera: Curculionidae)

O gorgulho-aquático-do-arroz Oryzophagus oryzae (Costa Lima) (Coleoptera: Curculionidae) é um dos insetos mais prejudiciais à cultura do arroz irrigado, devido aos danos causados pelas suas larvas às raízes da planta. A associação entre o teor de nitrogênio e o ataque de O. oryzae foi avaliada nas cultivares "BR IRGA 410", "BRS Firmeza", "Dawn" e "BRS Atalanta", diferenciadas pelo ciclo de desenvolvimento fenológico e pelo grau de resistência ao inseto, em experimentos no campo, com e sem chance de escolha de hospedeiro, na Embrapa Clima Temperado, Pelotas, Rio Grande do Sul. Determinaram-se o número de folhas lesionadas, o número e o peso de larvas do inseto e, em três épocas distintas, o teor de nitrogênio na parte aérea e nas raízes das plantas. A alimentação dos adultos de O. oryzae foi estimulada pelo teor de nitrogênio da parte aérea das plantas. A cultivar "Dawn", que apresentou menor número de larvas e maior ciclo de desenvolvimento fenológico, foi a única a recuperar o teor de nitrogênio. O dano às raízes, causado por larvas de O. oryzae, reduziu o teor de nitrogênio e, conseqüentemente, provocou perda na produção de grãos.

The rice water weevil Oryzophagus oryzae (Costa Lima) (Coleoptera: Curculionidae) is one of the most important pests in irrigated rice culture due to the damage caused by the larvae in the roots. The association between the nitrogen content and the O. oryzae damage was evaluated on BR IRGA 410, BRS Firmeza, Dawn and BRS Atalanta cultivars differentiated by the phenological development cycle and the insect resistance degree. The experiments were conducted under field conditions, with and without chance of host plant choice, at Embrapa Clima Temperado, Pelotas, RS. The following parameters were evaluated: number of damaged leaves, number and weight of larvae. The nitrogen content in the leaves and roots were evaluated at three different rice growth stages. The adult feeding of O. oryzae were stimulated by the content of nitrogen in the foliage of the plant. The cultivar Dawn was the only one to revover the nitrogen content, due to the presence of the smallest number of larvae and the largest development cycle in compare to other cultivars. The root damage caused by O. oryzae larvae decreased the nitrogen content, and consequently reduced the rice yield.

Efeito residual do extrato acetato de etila de Trichilia pallida Swartz ( Meliaceae ) para lagartas de diferentes idades de Spodoptera frugiperda ( J. E. Smith, 1797 ) ( Lepidoptera: Noctuidae ) / Residual effect of ethyl acetate extract of Trichilia pallida Swartz ( Meliaceae ) for Spodoptera frugiperda ( J. E. Smith, 1797 ) ( Lepidoptera: Noctuidae ) larvae of diferents ages

Inseticidas de origem vegetal mostram limitada persistência em condições ambientais já que são degradados pela temperatura, por raios ultravioletas e por outros fatores ambientais. Com o objetivo de avaliar o efeito residual do extrato acetato de etila de Trichilia pallida, plantas de milho cultivadas em casa de vegetação foram pulverizadas com o referido extrato na concentração de 2 por cento, e as suas folhas utilizadas para alimentação de lagartas de Spodoptera frugiperda, em laboratório. As folhas foram oferecidas às lagartas aos 1, 3 e 7 dias após a pulverização, correspondendo cada época a um tratamento. Foram utilizados dois grupos de lagartas: recém-eclodidas e com 10 dias de idade. As folhas foram trocadas diariamente e, 10 dias após o início do experimento, foram avaliados a mortalidade, a largura da cápsula cefálica e o peso das lagartas. Verificou-se que, nas três épocas, o extrato reduziu a sobrevivência e prolongou o desenvolvimento larval. A intensidade destes efeitos foi maior quanto menor o intervalo entre a aplicação do extrato e o início do fornecimento das folhas aos insetos. Lagartas alimentadas com folhas tratadas com o extrato desde a eclosão foram mais afetadas que aquelas alimentadas a partir dos 10 dias.

Bioactivity of neem, Azadirachta indica, against spittlebug Mahanarva fimbriolata (Hemiptera: Cercopidae) on sugarcane.

The effect of neem, Azadirachta indica A. Juss, on some biological parameters of Mahanarva fimbriolata (Stil) (Hemiptera: Cercopidae) was studied in the laboratory by using NeemAzal-T/S, Nimkol-LS, and an aqueous neem seed extract. Initially, the LC,, was estimated for nymphs. Later, nymphs fed on sugarcane, Saccharum officinarum L., roots were sprayed with the respective LC,, for each product. The adults were maintained in cages on sugarcane plants sprayed at the base with the maximum rate recommended commercially for the crop (3 liter/ha). Moistened cotton discs surrounding the base of the plant were used as oviposition substrates. The LCso values estimated for NeemAzal, Nimkol, and aqueous extract were 0.014, 0.225, and 0.611%, respectively. There was a reduction in spittlebug longevity, regardless of sex, in relation to the control. Males exposed to the neem products, and aqueous extract showed longevity reductions of approximately 50%, whereas for females the reductions were 55-60%. The neem products and extract reduced fecundity by 75-85%. Morphological and physiological changes were observed in 9% of the eggs from individuals submitted to NeemAzal. Neem-based products, especially NeemAzal, have potential for the control of M. fimbriolata.

Aspectos Biológicos de Zabrotes subfasciatus (Boh. ) (Coleoptera: Bruchidae) em Genótipos de Feijoeiro com e sem Arcelina / Biological Aspects of Zabrotes subfasciatus (Boh. ) (Coleoptera: Bruchidae) on Bean Genotypes with and without Arcelin

Bean genotypes containing arcelin (Arc1, Arc2, Arc3 and Arc4) and bean genotypes without this protein (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 and Goiano Precoce) were evaluated concerning the resistance to the Mexican bean weevil Zabrotes subfasciatus (Boh.), under laboratory conditions. The materials containing arcelin (Arc1, Arc2, Arc3 and Arc4) showed antibiotic effects on the insect, prolonging the development period (egg to adult), reducing male and female weight and longevity, and decreasing fecundity. The cultivars most suitable for the development and reproduction of this insect were Goiano Precoce, IAC Maravilha, Porrillo 70 and IAC Carioca Pyatã.

O objetivo deste trabalho foi avaliar o efeito de genótipos de feijões com e sem arcelina sobre alguns aspectos biológicos de Zabrotes subfasciatus (Bob.). Os insetos foram criados, em condições de laboratório, sobre materiais melhorados com arcelina (Arc1, Arc2, Arc3 e Arc4) e materiais sem essa proteína (IAC Carioca Aruã, IAC Carioca Pyatã, IAC Carioca Akytã, IAC Maravilha, IAC Una, IAC Bico de Ouro, Porrillo 70 e Goiano Precoce). Os materiais contendo arcelina (Arc1, Arc2, Arc3 e Arc4) provocaram efeitos antibióticos sobre o inseto, alongando o período de desenvolvimento, diminuindo o peso, a longevidade de machos e de fêmeas e a fecundidade. Os genótipos mais adequados ao desenvolvimento do inseto foram Goiano Precoce, IAC Maravilha, Porrillo 70 e IAC Carioca Pyatã.

Bioatividade de Extratos Aquosos de Melia azedarach L. Sobre o Desenvolvimento de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) em Tomateiro / Bioactivity of Aqueous Extracts of Melia azedarach L. on Tomato Pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

The effect of aqueous extracts of Melia azedarach L. on the development of the tomato pinworm Tuta absoluta (Meyrick) was investigated under laboratory conditions. After hatching, the larvae were fed on tomato leaves (Lycopersicon esculentum, cv. Santa Clara) treated with chinaberry's extracts. The larval and pupal development and mortality and pupal weight were evaluated. Firstly, the trials were carried out with three different concentrations of leaf extracts (0.1, 1.0 e 5.0 percent), in order to determine the most appropriate one for bioactivity studies. Later, the aqueous extracts of different parts of M. azedarach were compared using the selected concentration (0.1 percent). The leaf extract was the most effective for tomato pinworm bioactivity studies, followed by raw fruits, branches and ripe fruits.

Determinou-se, em condições de laboratório, o efeito de extratos aquosos de Melia azedarach L. sobre o desenvolvimento da traça-do-tomateiro Tuta absoluta (Meyrick). Para isso, as lagartas foram alimentadas, desde a eclosão, com folhas de tomateiro (Lycopersicon esculentum, cv. Santa Clara), tratadas com extratos dessa meliácea, avaliando-se a duração e viabilidade das fases larval e pupal e o peso de pupas. Inicialmente, foram testadas três concentrações (0,1; 1 e 5 por cento) do extrato de folhas, visando determinar a concentração adequada para estudos de bioatividade dessa planta. Posteriormente, utilizando-se a concentração selecionada (0,1 por cento), foi comparada a bioatividade dos extratos de diferentes estruturas de M. azedarach, constatando-se que as folhas foram a estrutura vegetal com maior bioatividade sobre a traça, vindo a seguir os frutos verdes, ramos e frutos maduros.