Interactions of maize bushy stunt phytoplasma with the leafhopper vector, Dalbulus maidis (Delong and Wolcott) (Hemiptera: Cicadellidae) and associated microbiota

Phytoplasmas are bacteria with a persistent propagative transmission by insect vectors that generates direct and indirect interactions among them. In order to understand these interactions for maize bushy stunt phytoplasma (MBSP) and the leafhopper vector Dalbulus maidis (Hemiptera: Cicadellidae), two research lines were addressed. The first one aimed to determine the indirect effects of maize infection by MBSP on some biological and behavioral parameters of the vector, whereas a second line investigated direct interactions of the phytoplasma with D. maidis during its movement through the vector body following acquisition from plants, and associated microbiota. Indirect effects were investigated in choice experiments in which alighting and oviposition preferences by D. maidis were compared on healthy vs. MBSP-infected plants with variable incubation time (diseased plants with early and advanced symptoms, or still asymptomatic). Likewise, indirect effect of MBSP on the D. maidis biology was determined in two life table experiments in which the vector was reared on healthy vs. MBSP-infected plants expressing advanced disease symptoms or still asymptomatic. Choice experiments showed that alighting and oviposition preferences of D. maidis on MBSP-infected plants compared to healthy plants depend on the pathogen incubation period in the plant. The leafhopper preferred MBSP-infected plants over healthy ones during the asymptomatic phase of the disease, but rejected infected plants with advanced symptoms. The vector was able to acquire MBSP from asymptomatic infected plants shortly (3 days) after inoculation, but transmission efficiency increased when acquisition occurred at later stages of the pathogen incubation period (≥14 days) in the source plants and the test plants showed disease symptoms faster. These results suggest that MBSP modulates D. maidis preference for asymptomatic infected plants in the early stages of the crop, allowing rapid spread of this pathogen. Maize infection by the phytoplasma had a neutral effect on most life table parameters of D. maidis; a lower net reproductivity rate (Ro) was observed in the cohort reared on MBSP-infected plants with advanced symptoms, which was compensated to some extent by a higher sexual ratio. MBSP acquisition by all vector nymphal stadia was confirmed by PCR, and the pathogen as detected in both male and female reproductive organs. Concerning direct MBSP-vector interactions, transmission electron microscopy analyses showed phytoplasma-like cells in the midgut lumen, microvilli and epithelial cells, suggesting that MBSP enters the epithelium midgut through the microvilli wall. Within the epithelial cells, mitochondria and bacteria-like cells (possibly endosymbionts) were observed together with masses of phythoplasma-like cells. In the hemocoel, phytoplasma-like cells grouped into a matrix were also observed in association with bacteria-like cells similar to those observed in the midgut epithelium. Similar associations were found in the salivary gland. Interestingly, in-situ hybridization (FISH) technique revealed a variation in diversity and abundance of the microbiota in intestine and salivary glands of D. maidis adults over time after MBSP acquisition from plants. Sulcia sp., Cardinium sp. and eubacteria increased their abundance over time, whereas Rickettsia sp. decreased. The frequent association of the vector microbiota with the phytoplasma in some tissues of D. maidis suggests that endosymbiotic bacteria may play some role in MBSP-vector interactions.

Método de desvio de obstáculos aplicado em veículo autônomo.

A operação de veículos autônomos necessita de meios para evitar colisões quando obstáculos não conhecidos previamente são interpostos em sua trajetória. Algoritmos para executar o desvio e sensores apropriados para a detecção destes obstáculos são essenciais para a operação destes veículos. Esta dissertação apresenta estudos sobre quatro algoritmos de desvio de obstáculos e tecnologia de três tipos de sensores aplicáveis à operação de veículos autônomos. Após os estudos teóricos, um dos algoritmos foi testado para a comprovação da aplicabilidade ao veículo de teste. A etapa experimental foi a realização de um programa, escrito em linguagem de programação Java, que aplicou o algoritmo Inseto 2 para o desvio de obstáculos em uma plataforma robótica (Robodeck) com o uso de sensores ultrassônicos embarcados na referida plataforma. Os experimentos foram conduzidos em ambiente fechado (indoor), bidimensional e horizontal (plano), fazendo o Robodeck executar uma trajetória. Para os testes, obstáculos foram colocados para simular situações variadas e avaliar a eficácia do algoritmo nestas configurações de caminho. O algoritmo executou o desvio dos obstáculos com sucesso e, quando havia solução para a trajetória, ela foi encontrada. Quando não havia solução, o algoritmo detectou esta situação e parou o veículo.

Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae): adequação de uma dieta artificial e avaliação do seu controle biológico com Trichogramma pretiosum Riley em tomateiro

Tuta absoluta (Meyrick, 1917) é uma das pragas-chave da cultura do tomate e outras solanáceas na América do Sul e atualmente também na Eurásia e África. Devido aos grandes prejuízos que causa à cultura, são principalmente usados inseticidas para o seu controle. Entretanto, na busca de estratégias mais sustentáveis, cada dia adquire maior importância o uso do controle biológico, como uma das estratégias do manejo integrado de pragas. Para o desenvolvimento destas estratégias é fundamental desenvolver um método de criação de T. absoluta em laboratório, em dieta artificial, sem necessitar do hospedeiro natural, muitas vezes difícil de ser obtido e mantido em laboratório, e, de grande importância para produzir parasitoides específicos para esta praga. Dentre os parasitoides mais usados para ovos de lepidópteros está Trichogramma pretiosum Riley 1879 que é usado no controle biológico aplicado desta praga. Tendo como foco principal T. absoluta, neste trabalho foram pesquisados 1) a seleção de uma dieta artificial para este lepidóptero baseando-se em características físicas e químicas, avaliando o seu desempenho por várias gerações em laboratório, e 2) avaliação de aspectos biológicos e reprodutivos de T. pretiosum parasitando ovos de T. absoluta e aspectos físicos da planta (tricomas) para compreender o controle biológico desta praga no tomateiro. Foi encontrado que uma dieta à base de germe-de-trigo, caseína e celulose é apropriada para a criação deste lepidóptero, já que o inseto mostrou adaptação à mesma no transcorrer das gerações com base em características biológicas e de tabela de vida; adicionalmente, os ovos provenientes de T. absoluta alimentada com dieta artificial são comparáveis aos da dieta natural, no parasitismo de T. pretiosum. Com relação ao controle biológico foi demonstrado que este parasitoide desenvolvido em ovos de T. absoluta, diminui seu tamanho e desempenho com o transcorrer das gerações, apresentando menor capacidade de voo do que os insetos produzidos em A. kuenhiella, sendo necessária a liberação de altas densidades de parasitoides por ovo da praga. Foi observado que, embora o parasitismo de T. pretiosum de ovos de T. absoluta seja melhor em variedades com poucos tricomas, uma alta densidade destas estruturas não impede o controle da praga alvo dependendo da disposição destas estruturas. O controle biológico de T. absoluta com T. pretiosum tem uma ação momentânea, sendo necessárias liberações frequentes devido ao fato de os parasitoides desenvolvidos na praga serem menos competitivos com aqueles provenientes do hospedeiro alternativo que apresenta ovos maiores do que T. absoluta.

Atividades biológicas de extratos salinos de sementes de plantas da caatinga contra Aedes Aegypti e investigação da participação de proteínas bioativas

Dengue fever, currently the most important arbovirus, is transmitted by the bite of the Aedes aegypti mosquito. Given the absence of a prophylactic vaccine, the disease can only be controlled by combating the vector insect. However, increasing reports of resistance and environmental damage caused by insecticides have led to the urgent search for new safer alternatives. Twenty - um plant s eed extracts from the Caatinga were prepared , tested and characterized . Sodium phosphate ( 50 mM pH 8.0) was used as extractor. All extracts showed larvicidal and ovipositional deterrence activity . Extracts of D. grandiflora, E. contortisiliquum, A. cearenses , C. ferrea and C. retusa were able to attract females for posture when in low co ncentration . In the attractive concentrations, the CE of E. contortisiliquum and A. cearenses were able to kill 52% and 100% of the larvae respectively . The extracts of A. cearenses , P. viridiflora, E. velutina, M. urundeuva and S. brasiliensis were also pupicides, while extracts of P. viridiflora, E. velutina, E. contortisiliquum , A. cearenses, A. colubrina, D. grandiflora , B. cheilantha , S. spectabilis, C. pyramidalis, M. regnelli e G. americana displayed adulticidal activity. All extracts were toxic to C. dubia zooplankton . The EB of E. velutina and E. contortisiliquum did not affect the viability of fibroblasts . In all extracts were identified at least two potential insecticidal proteins such as enzyme inhibitors, lectins and chitin - binding proteins and components of secondary metabolism . Considering all bioassays , the extracts from A. cearenses, P. viridiflora, E. contortisiliquum , S. brasiliensis, E. velutina and M. urundeuva were considered the most promising . The E. contortisiliquum extracts was the only one who did not show pupicida activity, indicating that its mechanism of action larvicide and adulticidal is related only to the ingesti on of toxic compounds by insect , so it was selected to be fragmenting. As observed for the CE , th e protein fractions of E. contortisiliquum also showed larvicidal activity, highlighting that F2 showed higher larvicidal activity and lower en vironmental toxicity than the CE source. The reduction in the proteolytic activity of larvae fed with crude extra ct and fractions of E. contortisiliquum suggest ed that the trypsin inhibitors ( ITEc) would be resp onsible for larvicidal activity . However the increase in the purification of this inhibitor resulted in loss of larvicidal activity , but the absence of trypsin inhibitor reduced the effectiveness of the fractions , indicating that the ITEC contributes to the larvicidal activity of this extract. Not been observed larvicidal activity and adulticide in rich fraction vicilin, nor evidence of the contribution o f this molecule for the larvicidal activity of the extract. The results show the potential of seeds from plant extracts of Caatinga as a source of active molecules against insects A. aegypti at different stages of its development cycle, since they are comp osed of different active compounds, including protein nature, which act on different mechanisms should result in the death of insec

Distribuição da fauna triatomínica e infecção natural pelo Trypanosoma cruzi em diferentes municípios do semiárido do Rio Grande do Norte

The triatomine fauna distribution and the natural infection by Trypanosoma cruzi was evaluated aiming the comprehension of the transmission dynamics of this parasite in the countryside of the State of Rio Grande do Norte. Additionally, the research for Trypanosoma rangeli was also investigated. The captures of triatomines were performed at sylvatic, peridomicile and domicile environments at different municipalities of the central and western mesoregions of this state. The insects were identified and examined by direct method, xenoculture and PCR to detect T. cruzi. The detection of T. rangeli was performed by direct examination of the hemolymph and multiplex PCR of 151 positive specimens for T. cruzi. Of 824 captured insects, the species were distributed in Triatoma brasiliensis (66.4%), Triatoma pseudomaculata (18.2%), Panstrongylus lutzi (12.7%) and Rhodnius nasutus (2.7%), and T. brasiliensis was found in most of the evaluated municipalities. The species were captured at nymph and adult stages, except P. lutzi, exclusively in adult stage. In the sylvatic environment were captured T. brasiliensis (57%), P. lutzi (28%) and T. pseudomaculata (15%) species. At the peridomicile environment were identified T. brasiliensis (74%), T. pseudomaculata (21%) and R. nasutus (5.0%), while in the intradomicile was found only T. brasiliensis. The infection rate of triatomines by T. cruzi was 30.4%, P. lutzi showed highest rate (78%), followed by T. brasiliensis (24.4%), T. pseudomaculata (22.6%) and R. nasutus (4.5%). Infected triatomines indexes at silvatic, peridomicile and domicile environments were of 41.8%, 20.1% and 50.0%, respectively. T. rangeli was only detected by multiplex PCR in 2.6% (4/151) of examined insects, of these 4.4% (3/67) were T. brasiliensis and 1.5% (1/63) P. lutzi species. The data showed that the positivity of P. lutzi allied to its ability to invade domicile attracted by light, suggests a likely participation of this insect between epidemiological transmission cycles of T. cruzi. T. brasiliensis was the only specie present in all environments, what reinforces its importance related to the capacity for adapting to the domestic environment, potential as a vector, and maintenance of sylvatic and domestic transmissions cycles in the semiarid, indicating the necessity of continuous epidemiological surveillance. The presence of T. rangeli in T. brasiliensis and P. lutzi was first recorded in rural zone of this State, broadening the area of occurrence of this protozoan in northeastern Brazil.

Distribuição da fauna triatomínica e infecção natural pelo Trypanosoma cruzi em diferentes municípios do semiárido do Rio Grande do Norte

The triatomine fauna distribution and the natural infection by Trypanosoma cruzi was evaluated aiming the comprehension of the transmission dynamics of this parasite in the countryside of the State of Rio Grande do Norte. Additionally, the research for Trypanosoma rangeli was also investigated. The captures of triatomines were performed at sylvatic, peridomicile and domicile environments at different municipalities of the central and western mesoregions of this state. The insects were identified and examined by direct method, xenoculture and PCR to detect T. cruzi. The detection of T. rangeli was performed by direct examination of the hemolymph and multiplex PCR of 151 positive specimens for T. cruzi. Of 824 captured insects, the species were distributed in Triatoma brasiliensis (66.4%), Triatoma pseudomaculata (18.2%), Panstrongylus lutzi (12.7%) and Rhodnius nasutus (2.7%), and T. brasiliensis was found in most of the evaluated municipalities. The species were captured at nymph and adult stages, except P. lutzi, exclusively in adult stage. In the sylvatic environment were captured T. brasiliensis (57%), P. lutzi (28%) and T. pseudomaculata (15%) species. At the peridomicile environment were identified T. brasiliensis (74%), T. pseudomaculata (21%) and R. nasutus (5.0%), while in the intradomicile was found only T. brasiliensis. The infection rate of triatomines by T. cruzi was 30.4%, P. lutzi showed highest rate (78%), followed by T. brasiliensis (24.4%), T. pseudomaculata (22.6%) and R. nasutus (4.5%). Infected triatomines indexes at silvatic, peridomicile and domicile environments were of 41.8%, 20.1% and 50.0%, respectively. T. rangeli was only detected by multiplex PCR in 2.6% (4/151) of examined insects, of these 4.4% (3/67) were T. brasiliensis and 1.5% (1/63) P. lutzi species. The data showed that the positivity of P. lutzi allied to its ability to invade domicile attracted by light, suggests a likely participation of this insect between epidemiological transmission cycles of T. cruzi. T. brasiliensis was the only specie present in all environments, what reinforces its importance related to the capacity for adapting to the domestic environment, potential as a vector, and maintenance of sylvatic and domestic transmissions cycles in the semiarid, indicating the necessity of continuous epidemiological surveillance. The presence of T. rangeli in T. brasiliensis and P. lutzi was first recorded in rural zone of this State, broadening the area of occurrence of this protozoan in northeastern Brazil.

Toxicidade de extratos vegetais ao percevejo bronzeado do eucalipto Thaumastocoris peregrinus (hemiptera: heteroptera: thaumastocoridae) e organismos não-alvo

Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae ) is an insect from Australia which is causing severe damage to eucalyptus crops around the world. When feeding from the leaves sap, it causes bronzening, and in extreme cases, may lead to the tree death. Control methods have been studied and the most promising so far is the egg parasitoid Cleruchoides noackae (Hymenoptera: Mymaridae). Alternative products from plants with insecticidal properties could also be a viable option, and they might even be used concomitantly with C. noackae, aiming for a most effective control, but still safe for the environment. Thus, the objective of this work was to verify the action of 5% aqueous plant extracts of Matricaria chamomilla, Echinodorus grandiflorus, Punica granatum, Maytenus ilicifolia a n d Origanum majorana on T. peregrinus. In addition, we aimed to study the extracts potential toxicity to C. noackae and Gallus domesticus L., since the plant compounds might have negative effect upon the non-target organisms. At first, HPLC (High Performance Liquid Chromatography) was used to verify which phenolic compounds would be found in the plant extracts. These were tested on bronze bug adults, in confinement test (to verify the insecticidal action of the extracts) and free-choice test (to verify the repellency). The extracts that showed better results were selected for further tests with non-target organisms. Regarding C. noackae, pre-parasitism and post-parasitism, confinement and free-choice tests were performed to verify if the extracts would affect the host-choosing by the female or the development of the immature stages of the parasitoid. To verify if the extracts would be toxic to G. domesticus, the plant extracts were added to young birds feed for five days. Parameters such as weight gain, food intake, quantification of serum enzymes and histopathological analysis were carried out. HPLC analysis detected gallic, ferulic, vanillic, caffeic and cumaric acid in the extracts samples. All plant extracts tested reduced T. peregrinus survival, but E. grandiflorus, Matricaria chamomilla Maytenus ilicifolia had also a repellent effect, and were tested on the non-target organisms. None of these extracts affected neither the host choice by C. noackae nor adult emergency, when compared to the control group. In addition, the extracts did not cause alterations in any of the studied parameters. Thus, we verified that E. grandiflorus, Matricaria chamomilla and Maytenus ilicifolia have potential to be used to control T. peregrinus and are safe to C. noackae and G. domesticus.

Macrofauna epígea de besouros coprófilos em sistema de integração lavoura-pecuária

The soil macrofauna (organisms ≥ 2.0 mm) main function is to act indirectly on the decomposition of organic matter and control the population of microorganisms. This study aims to evaluate the density and richness of coprphilic dung beetles at different levels of nitrogen fertilization and grazing pressure on Crop-Livestock Integration System (ILP) and his opposition to morphotypes present in the native forests of the region. Was used a rural area in Abelardo Luz city, western state of Santa Catarina, on the border of southwest of Paraná, 26° 31' 18.8832" south latitude and 52° 15' 3.4986' west longitude and elevation 862 m for the installation of the experiment, which is already carried out the activity of agriculture and livestock. The study is part of the Integrated Project of Long Duration GISPA UTFPR Group, which evaluates the grazing pressure and time of fertilization deployed in April 2013. The experimental design was a randomized complete block design in a 2x2 factorial arrangement with three replications. The factors were "Nitrogen Application" (NP = N in the pasture and NG = N applied in corn) and "Height Grazing" (high and low). The native forest, which provided the parameters for assessing the degree of conservation, lies 700 meters northeast of the experimental area. Modified pitfall traps were used at ground level, on the bait trap and covered together to prevent dehydration. They were carried out 36 collections in bushland, within one year from 26 April 2013, in which we obtained a total of 16,301 individuals and 28 morphotypes. In ILP area specimens were collected from June to September 2014, totaling 23 collections, 74,586 individuals and 30 morphotypes. To carry out the statistics and faunal analysis, GENES programs were used, ANAFAU, NTIA/EMBRAPA and SigmaPlot version 12.5. Most of the correlations observed (90%) between the variables of insects and environmental conditions was significant. The largest number of insects was directly related to the temperature rise. There was a positive correlation between the application of nitrogen and the occurrence of coprophilous. There was a positive correlation between the number of insects and low grazing height. It was also found that some of the insects migrate from the culture to the area of native forest after reaching their peak population. The great similarity of results observed in the native forest and the ILP System indicates the ecological benefits of adopting this technology.

Resposta imune à saliva de flebotomíneos (diptera: psychodidae) em indivíduos residentes em áreas urbana e periurbana no nordeste do brasil

Visceral leishmaniasis (VL) has a wide geographical distribution in tropical and subtropical areas of the planet, which is a protozoan parasite of the genus Leishmania. This pathogen is transmitted to the host through the sandflies bite, with its saliva, the immune response that leads to both. In the state of Rio Grande do Norte, 85% of the sand flies captured is Lutzomyia longipalpis, but the second most abundant, Lutzomyia evandroi, it deserves emphasis because its wide distribution and eclectic behavior. The exposure of people living in endemic areas for the insect vector VL greatly increases the chances of infection. This study aimed to evaluate aspects of the epidemiological profile of VL in endemic areas of human and nonendemic in the metropolitan area of Natal, as well as verify the abundance and seasonal fluctuations of sandflies species in two counties endemic for VL. Were collected in the municipalities of Nísia Floresta, Parnamirim, São Gonçalo do Amarante and Macaíba, of which groups of females were separated for further dissection of the salivary glands and identification of species. The blood samples used were from individuals of two Natal s districts where it has never been reported cases of VL and neighborhoods of Parnamirim applicants who present cases of VL. In the municipality of Nísia Floresta, the most abundant species was L. evandroi with 38.39%, followed by L. longipalpis with 36.22%, L. walkeri 19.67% L. lenti 3.81%, L. wellcomei 1.39% and L. whitmani 0.52%. Already in Parnamirim the proportions were L. walkeri with 73.15%, L. evandroi with 10.55%, L. wellcomei 7.63%, L. longipalpis 6.37%, L. whitmani 1.46%, L. sordellii 0.52%, L. intermedia 0.21 and L. shanonni 0.1%. In both municipalities was observed higher abundance of species distributed in the initial months of the year, as February and March. The study showed that no difference in exposure to the vector of VL among individuals from endemic and non endemic area for this disease. But there are differences in exposure between individuals of L. longipalpis and L. evandroi, confirming the great powers of the first vector. It was also characterized as predominant phenotype in the population of endemic areas who had negative serologic responses to antigens of Leishmania and result in negative Montenegro skin test (DTH), indicating that much of the population hasn t been bitten by infected insects

Vicilina de sementes da leguminosa selvagem Anadenanthera macrocarpa: purificação, caracterização, efeito deletério e mecanismo de ação para Callosobruchus maculatus

Grains and legume seeds are foods that form the basis of the diets of many cultures around the world, winch contritbute to the daily nutrient requirements of humans. Vicilins (7S globulin) are storage proteins found in legume seeds, and may have an additional function constitutive defense of the embryo against pests and pathogens. In this work the vicilin from Anadenanthera macrocarpa - AmV (red-angico), was purified and partially characterized, its effect on development and larval survival and adult emergence of Callosobruchus maculatus was evaluated by determination of LD50, WD50 and ED50 in system bioassay. Purification of vicilin was initiated by the chitin affinity chromatography and then gel filtration (Superdex 75 Tricorn 10x300 mm) FPLC system followed by reverse phase chromatography (C8 phenomenex) on HPLC system. Bioassays WD50 and LD50 for larvae were 0.32% and 0.33% (w:w) respectively, since the ED50 for adults was 0.096%. The probable mechanism of action was evaluated by testing digestibility of AmV in vitro, and observed for the involvement of two fragments vicilins immunoreactive against polyclonal Anti-vicilin from Erythrina velutina (Anti-EvV) about of 22 and 13 kDa chitin binding. The AmV in its native form has been recognized by the anti-EvV, indicating that there is a conserved region in the vicilin and is probably corresponding to the chitin binding domains. These results point to a new vicilin chitin binding that can subsequently be used as a possible biopesticide protein source, in order to control insect pest C. maculatus and confirm literature findings that demonstrate vicilin in the presence of different kinds of ligands to conserved regions chitin not yet characterized

Compuestos cuticulares de Euschisthus heros (F.) (Heteroptera: pentatomidae) y su papel en las etapas inciales de la infección por hongos entomopatógenos.

2015

Acaros fitofagos no Nordeste do Brasil.

Este trabalho apresenta as especies de Tetranychidae (18 especies), Tenuipalpidae (2 especies), Eriophyidae (3 especies)(, Rhyncaphytoptidae (1 especie) e Tarsonemidae (1 especie) coletadas no Nordeste. Apresenta tambem chaves para a separacao dos generos de Tetranychidae, Tenuipappidae e Eriphyidae encontrados, e dados sobre distribuicao e hospedeiros.

Aspectos biologicos do acaro vermelho do tomateiro.

Alguns aspectos biologicos de Tetranychus evansi Baker & Pritchard foram estudados em laboratorio, incluindo a duracao das formas jovens e a capacidade reprodutiva, em plantas de tomate var. Rossol. As duracoes dos estagios do ovo, larva, protoninfa e deutoninfa foram de 4,8; 2,6, 2,4 e 3,2 dias, respectivamente, correspondendo a uma duracao total de, aproximadamente treze dias de ovo a adulto, para ambos os secos. Os niveis mais altos de oviposicao foram obtidos do quarto ao decimo ia, aproximadamente. Uma media de 105,7 ovos foram postos durante todo o periodo de oviposicao. Provavelmente, a utilizacao de folhas medianas ou basais, ao inves de apicais, como substrato teria resultado em um ciclo biologico mais curto e em uma oviposicao total maior do que os obtidos neste estudo.

Etapas do desenvolvimento de uma formulação pó molhável para o Baculovirus anticarsia: secagem e caracterização da superfície do poliedro.

As primeiras etapas selecionadas para o estudo de uma formulação pó molhável foram a caracterização de superfície quanto a morfologia (MEV) e carga, e a influencia do método de secagem na dispersibilidade das partículas. O vírus foi obtido de lagartas infectadas (CNPSo) e purificado pelo método de Van der Geest. A dispersão resultante apresenta uma distribuição de tamanho entre 1.6 e 1.9 micra, permanecendo invariável quando a preparação foi armazenada ate 6 meses sob refrigeração. O ponto isoelétrico dos poliedros de NPV de B. anticarsia, determinado a partir de gráfico de mobilidade versus pH e 4,5, sendo que em pHs superiores, as partículas estão carregadas negativamente. As dispersões foram secas por liofilização, spray dryer e estufa (27 C.). O processo de secagem determina o estado de agregação, quando os poliedros são dispersos novamente em água, com tamanho ate 27 micra, difíceis de redispersar, enquanto a secagem por spray dryer resulta em um material pouco aglomerado e facilmente dispersível.

Biologia da traca do tomateiro sob condicoes de laboratorio.

Estudaram-se, no CPATSA-EMBRAPA em Petrolina, PE, sob condicoes de laboratorio, os aspectos biologicos de Scrobipalpula absoluta (Meyrick 1917) (Lepidoptera,Gelechiidae), importante praga do tomateiro, Iniciou-se a criacao com larvas coletadas no campo, em cultura de tomate, acondicionadas, em placas de Petri, sobre papel de filtro e folhas de tomateiro, variedade IPA-2. Os adultos foram mantidos em frascos de vidro revestidos com papel sulfite, tampados com tecido branco de nailon preso com elastico e alimentados, com uma solucao de sacarose a 10%, embebida em algodao. Obtiveram-se os seguintes dados: periodo de pre-ovoposicao 2,35 dias; numero de ovos por femea 55,16; viabilidade de ovos 44,46%, periodo de incubacao 4,30 dias; periodo de oviposicao 3,77 dias; periodo larval 10,95 dias com quatro instares; viabilidade larval 20,97%; periodo pupal 6,15 dias; viabilidade pupal 68,19%; longevidade de adultos machos e femeas 9,69 e 11,52 dias, respectivamente; ciclo biologico (ovo-morte do adulto) 38,12 dias.