Acute lethal and sublethal effects of neem leaf extract on the neotropical freshwater fish Prochilodus lineatus

The aim of this study was to determine the toxicity of the aqueous extract of neem leaves, a product extensively used in fish-farms as alternative for the control of fish parasites and fish fry predators, for the neotropical fish Prochilodus lineatus. The 24 It LC(50) of neem leaf extract for juveniles P lineatus was estimated as 4.8 g L(-1); the fish were then exposed for 24 h to 2.5, 5.0 and 7.5 g L(-1) or only clean water (control). Plasma glucose levels were higher in fish exposed to 2.5 g L(-1) and 5.0 g L(-1) neem extract, relative to control, indicating a typical stress response. Neem extract did not interfere with the osmoregulating capacity of the fish, as their plasma sodium, chloride, total protein and osmolarity did not change. The presence of the biopesticide interfered with the antioxidant defense system of P. lineatus, as there was a decrease in liver catalase activity at all neem concentrations and the detoxifying enzyme glutathione-S-transferase was activated in fish exposed to 5.0 g L(-1). Fish exposed to all neem extract concentrations exhibited damaged gill and kidney tissue. These results indicate that although neem extract is less toxic to P. lineatus than other synthetic insecticides used in fish-farming it does cause functional and morphological changes in this fish species. (c) 2006 Elsevier B.V. All rights reserved.

Efeito de beauveria bassiana (bals.) Vuillemin eMetarhizium anisopliae (metsch.) sorokin nos parâmetros biológicos de trichogramma atopovirilia oatman & platner, 1983 (hymenoptera: trichogrammatidae)

Two bioassays were performed to evaluate the effect of two biopesticides based on Beauveria bassiana (Bals.) Vuillemin and Metarhizium anisopliae (Metsch.) Sorokin on the biological parameters of Trichogramma atopovirilia Oatman & Platner, 1983. In the first one, displays with S. frugiperda, 1797 eggs were dropped into the biopesticide suspension and offered to the parasitoid females for 24 hours. In the second one, parasitoid females were fed with a suspension containing honey and biopesticide suspension. In both cases, after the parasitoid death they were mantained into a humid chamber to observe fungus sporulation. The experiments were maintained in a climatized chamber at 25 +/- 1 degrees C, RH 70 +/- 10%, and photophase of 14 hours. The longevity and adult mortality, total parasitism, progeny emergency, number of individuals per egg and sexual ratio were analyzed. The biopesticides did not affect the evaluated parameters and no fungus sporulation was observed in dead females. It is possible to assert that the entomopathogenic fungi B. bassiana and M. anisopliae can be used with T. atopovirilia in IPM S. frugiperda systems.

Allergenic extracts from Metarhizium anisopliae: Obtainment and characterization

Metarhizium anisopliae is used as a biopesticide for insects that damage agricultural plantations like sugar cane and forage plants. In a previous study the sensitization to this fungus of asthmatic patients coming from sugar cane areas was showed. The aims of this work were: to compare crude extracts obtained with Tris-HCl and Coca liquid from several growth phases of M. anisopliae concerning the total content of proteins and their electrophoretic analysis profile; to evaluate in vivo allergic sensitization in Balb/c mice and allergic patients from a sugar cane area, and to characterize the allergenic fractions in the sera of patients positive for the prick test by means of Western-blotting. The extract obtained with Coca liquid on the 16(th) day was the one that presented the greatest number of proteic fractions, including all those present in the other extracts. Twelve fractions were verified in this extract with approximate molecular weights from 94 to 14 kDa. The allergenicity of the extract obtained on the 16(th) day was proven by the production of IgE antibodies in Balb/c mice, with titres of 200. Prick tests carried out with the extract of the 16(th) day in 79 atopic individuals (from sugar cane area), 35 atopic individuals (from urban area) and 11 non- atopic individuals showed respective positivity of 29%, 9% and 0%. The allergenic characterization in vitro was performed by means of Western blotting, and the fractions that reacted with the positive individuals' sera were those of approximate molecular weights of 67 kDa (95%); 20 kDa (55%); 94 kDa (36%); 34 and 36 kDa (23%); 43 and 48 kDa (14%): 16 kDa (9%) and 54kDa (5%). It was concluded that the crude allergenic extract, obtained with Coca liquid from the 16(th) day growth of Metarhizium anisopliae, contains allergenic fractions and can be used in diagnostic screening tests.

Bacillus thuringiensis development from 1971 to 1996: Cases of a research group in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Susceptibility of Apis mellifera (Hymenoptera: Apidae) to pellitorine, an amide isolated from Piper tuberculatum (Piperaceae)

The acute toxicity of pellitorine, an amide isolated from Piper tuberculatum (Piperaceae) which is studied as a biopesticide in European corner borer, was evaluated on larvae and newly emerged adults of honeybee Apis mellifera by means of contact and ingestion bioassays. Workers in the larval and adult phase were separated in groups, which received pellitorine in different concentrations. The larvae were maintained in their own original cells, receiving feeding and normal care from the nurses. The adults were confined in wooden cages with screens, receiving artificial diet made up of sugar and water (1:1). The concentrations of 40, 200, 1 000, 5 000 and 25 000 ng a.i./individual were obtained diluting pellitorine in 98% ethanol. LD10 values of 39.14, 36.16 and 13.79 ng a.i./insect were determined for larvae, for adults by ingestion and adults by contact, respectively. The honeybee larvae were shown to be highly susceptible to the amide pellitorine.

Avaliação de dois diferentes meios de cultura para o desenvolvimento de biopesticidas à base de Bacillus thuringiensis e sua aplicação em larvas de Aedes aegypti

The bacteria Bacillus thuringiensis var. israelensis (Bti) generates certain toxins with pesticide action, which can be used on the control of transmissible diseases by culicides, specially Aedes aegypti, the dengue vector. This biopesticide has been produced by submerged fermentation and, in Brazil, this production has been made by very little research centers and, more recently, by a unique small enterprise. For the implementation of a viable vectors control program through biopesticides, some studies about culture media are essential in order to join efficiency and low costs. In this way, agroindustrial wastes or by-products have been used as a nutrient source for the culture media production. In this study, corn steep liquor, a corn industrial processing by-product and tryptose, both with/without sugar addition, were compared as culture media. Cellular growth was evaluated by optical density at 620 nm, spore production by total viable cell count and LC50 by bioassays against 4th instar larvae. Among the four examined substrates, the medium composed by glucose plus corn steep liquor presented the best spore production and bioassay results.

Development of a new method to prepare nano-/microparticles loaded with extracts of azadirachta indica, their characterization and use in controlling plutella xylostella

Biodegradable nanoparticles have been widely explored as carriers for controlled delivery of therapeutic molecules; however, studies describing the development of nanoparticles as carriers for biopesticide products are few. In this work, a new method to prepare nanoparticles loaded with neem (Azadirachta indica) extracts is presented. In this study, nanoparticles were formulated as colloidal suspension and (spray-dried) powder and characterized by evaluating pH, particle size, zeta potential, morphology, absolute recovery, and entrapment efficiency. A high-performance liquid chromatography method was used for nanoparticle characterization. The best formulations presented absolute recovery and entrapment efficiencies of approximately 100% and a release profile based on swelling and relaxation of the polymer or polymer erosion. The biological data of the formulated products against Plutella xylostella showed 100% larval mortality. The nanoparticle information improved the stability of neem products against ultraviolet radiation and increased their dispersion in the aqueous phase. © 2013 American Chemical Society.

Action of neem oil (Azadirachta indica A. Juss) on cocoon spinning in Ceraeochrysa claveri (Neuroptera: Chrysopidae)

Neem oil is a biopesticide that disturbs the endocrine and neuroendocrine systems of pests and may interfere with molting, metamorphosis and cocoon spinning. The cocoon serves protective functions for the pupa during metamorphosis, and these functions are dependent on cocoon structure. To assess the changes in cocoon spinning caused by neem oil ingestion, Ceraeochrysa claveri larvae, a common polyphagous predator, were fed with neem oil throughout the larval period. When treated with neem oil, changes were observed on the outer and inner surfaces of the C. claveri cocoon, such as decreased wall thickness and impaired ability to attach to a substrate. These negative effects may reduce the effectiveness of the mechanical and protective functions of cocoons during pupation, which makes the specimen more vulnerable to natural enemies and environmental factors. © 2013 Elsevier Inc.

Obtenção de bioinseticida a partir de Bacillus thuringiensis var. israelensis e aplicação de bioensaios em culicídeos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of UV-B radiation on Lecanicillium spp., biological control agents of the coffee leaf rust pathogen

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito Pesticida de Ésteres de Sacarose Sobre Calacarus heveae Feres (Acari: Eriophyidae) em Dois Clones de Seringueira

Sucrose esters are biodegradable, non pollutant and safe for health; moreover, they have shown great potential in the pest control. We tested a crude mix of sucrose esters on the survivorship and oviposition of Calacarus heveae Feres (Acari: Eriophyidae) females, an important rubber tree pest mite. The females were collected from rubber leaflets of the GT 1 and RRIM 600 clones. The mites were kept on stock arenas placed in rearing chamber at 28 + 0,1°C, 80 + 10% of relative humidity and 12h of light phase about two weeks before the assays. After this period, the mites were transferred to assay arenas made with leaflets from the same clone of stock arenas. The survivorship of females sprayed with sucrose esters in the concentrations of 1, 2, 3 and 4 g/L and their oviposition effect with 0.5 and 1 g/L were analyzed. The mites sprayed with 4 g/L had about 80% of mortality, while those with 1 g/L around 60%. All mites that died in the treatments with sucrose ester became dark with wrinkled tegument and decreased their body volume, suggesting dehydration. We also observed the efficacy of 1 g/L concentration to decrease the female oviposition in about 50%, in the third day after spraying. No differences were observed in the mortality and oviposition between females kept on both clones.

A dengue como ferramenta de interdisciplinaridade e popularização científica entre estudantes de ensino fundamental

The majority of the population knows their role in dengue control, preventing the accumulation of water in containers as potential breeding sites of Aedes aegypti, the main vector of dengue. Also known chemical control, widely used by the institutions responsible for the control of endemic diseases. On the other hand, unaware that an alternative measure such biological control through a microbial biopesticide, safe, harmless to health and the environment, can be adopted. Thus, this work reported for elementary school students, simply and clearly, the biological control of mosquitoes through bacterial biopesticide produced locally. Moreover, promoted the interdisciplinary teaching of science and mathematics through the data tabulation and charting on interviews conducted by students, about the level of knowledge of the population about dengue and other related variables.

Insecticidal Effect of Extracts from Native Plants of Mato Grosso do Sul State on Sitophilus zeamais Mots (Coleoptera: Curculionidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cytotoxic effects of neem oil in the midgut of the predator Ceraeochrysa claveri

Studies of morphological and ultrastructural alterations in target organs have been useful for evaluating the sublethal effects of biopesticides regarded as safe for non-target organisms in ecotoxicological analyses. One of the most widely used biopesticides is neem oil, and its safety and compatibility with natural enemies have been further clarified through bioassays performed to analyze the effects of indirect exposure by the intake of poisoned prey. Thus, this study examined the cellular response of midgut epithelial cells of the adult lacewing, Ceraeochrysa claveri, to neem oil exposure via intake of neem oil-contaminated prey during the larval stage. C. claveri larvae were fed Diatraea saccharalis eggs treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval stage. The adult females obtained from these treatments were used at two ages (newly emerged and at the start of oviposition) in morphological and ultrastructural analyses. Neem oil was found to cause pronounced cytotoxic effects in the adult midgut, such as cell dilation, emission of cytoplasmic protrusions, cell lysis, loss of integrity of the cell cortex, dilation of cisternae of the rough endoplasmic reticulum, swollen mitochondria, vesiculated appearance of the Golgi complex and dilated invaginations of the basal labyrinth. Epithelial cells responded to those injuries with various cytoprotective and detoxification mechanisms, including increases in cell proliferation, the number of calcium-containing cytoplasmic granules, and HSP 70 expression, autophagic processes and the development of smooth endoplasmic reticulum, but these mechanisms were insufficient for recovery from all of the cellular damage to the midgut. This study demonstrates that neem oil exposure impairs the midgut by causing sublethal effects that may affect the physiological functions of this organ, indicating the importance of studies of different life stages of this species and similar species to evaluate the safe and compatible integrated use of biopesticides.

Avaliação da capacidade de renovação do epitélio do mesêntero e seus efeitos no potencial reprodutivo de fêmeas adultas de Ceraeochrysa claveri (Neuroptera: Chrysopidae) alimentadas durante a fase larval com óleo de nim (azadirachta indica A. JUSS)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)