ResumoEste estudo avaliou a ação inseticida sistêmica e o efeito residual de nanoformulações à base de derivados de nim (Azadirachta indica A. Juss, Meliaceae) sobre ninfas de Bemisia tabaci biótipo B (Hemiptera: Aleyrodidae), espécie-praga de diversas culturas de importância econômica. Suspensões coloidais contendo nanocápsulas carregadas com produtos derivados de A. indica foram preparadas utilizando polímeros biodegradáveis como poli-ε-caprolactona (PCL) e poli-β-hidroxibutirato (PHB). A matriz encapsulada era composta por uma formulação comercial contendo uma quantidade enriquecida e conhecida dos limonoides azadiractina e 3-tigloilazadiractol (Azamax  1,2 CE). Inicialmente foi estimada a CL 50 , para ninfas de B. tabaci, de soluções contendo óleo de nim, que foram aplicadas via água de irrigação (solo) em tomateiro. Posteriormente, dois lotes de nanoformulações, com variação no tipo e quantidade dos polímeros e na quantidade do óleo comercial, foram testados quanto à ação sistêmica. As nanoformulações NC L5-2 (com nanocápsulas de PCL) e NC L6-1 (com nanocápsulas de PHB), as mais eficazes entre as testadas, foram avaliadas quanto ao efeito residual. A CL 50 estimada foi de 180,67 mg L -1 de azadiractina. Constatou-se também que a ação sistêmica de óleos e nanoformulações contendo compostos de nim dependem das condições ambientais em que são aplicados. O Azamax  não apresenta efeito deterrente sobre a oviposição, nem age sobre o desenvolvimento embrionário da mosca-branca quando aplicado via água de irrigação no solo no momento da infestação. As nanoformulações selecionadas são bioativas mesmo cerca de 30 dias após a aplicação, não diferindo do produto comercial.Palavras-chave: nanotecnologia, bioatividade, MIP, Azadirachta indica. Systemic insecticidal effect of neem-based nanoformulations against Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B in tomato AbstractThis study evaluated the systemic insecticidal action and the residual effect of neem-based nanoformulations (Azadirachta indica A. Juss, Meliaceae) on Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) nymphs, a pest of several economic important crops. Colloidal suspensions containing nanocapsules loaded with derived products from A. indica were prepared by using biodegradable polymers such as poly-ε-caprolactone (PCL) and poly-β-hydroxybutyrate (PHB).The encapsulated matrix was a commercial formulation, which contained not only enriched amount of limonoids azadirachtin and 3-tigloilazadiractol, but also in known quantities (Azamax  1.2 CE). Initially, it was estimated the LC 50 of solutions containing neem oil, which were applied through irrigation water (soil) in tomato in order to control nymphs of B. tabaci. Afterwards, two lots of nanoformulations, varying in type and amount of polymers and in quantity of commercial oil, were evaluated for systemic action. The nanoformulations NC L5-2 (nanocapules in PCL) and NC L6-1 (nanocapsules in PHB) caused higher mortality among others and for this reason were assayed for residual effect. The estimat...

Neem (Azadirachta indica) has attracted the attention of researchers worldwide due to its repellent properties and recognized effects on the morphology and physiology of arthropods, including ticks. Therefore, this study aimed to demonstrate the effects of neem seed oil enriched with azadirachtin on salivary glands of Rhipicephalus sanguineus ticks, targets of great veterinary interest because of their ability to transmit pathogens to dogs. For this, R. sanguineus semi-engorged females were subjected to treatment with neem seed oil, with known azadirachtin concentrations (200, 400 and 600ppm). After dissection, salivary glands were collected and evaluated through morphological techniques in light microscopy, confocal scanning laser microscopy and transmission electron microscopy, so that the possible relation between neem action and further impairment in these ectoparasites feed performance could be established. Neem oil demonstrated a clear dose-dependent effect in the analyzed samples. The agranular (type I) and granular acini (types II and III) showed, particularly in individuals treated with the highest concentrations of the product, cells with irregular shape, intense cytoplasmic disorganization and vacuolation, dilation of rough endoplasmic reticulum lumen, besides alterations in mitochondrial intermembrane space. These morphological damages may indicate modifications in salivary glands physiology, demonstrating the harmful effects of compounds present in neem oil on ticks. These results reinforce the potential of neem as an alternative method for controlling R. sanguineus ticks, instead of synthetic acaricides.

Recebido em 10/5/12; aceito em 18/9/12; publicado na web em 26/10/12 PHYTOCHEMICAL AND CHEMOSYSTEMATICS STUDIES OF Conchocarpus marginatus AND C. inopinatus (Rutaceae). Phytochemical studies of the leaves and stem have led to the identification of the known acridone alkaloids arborinine, methylarborinine, 1-hydroxy-3-methoxy-N-methyl acridone, xanthoxoline, 1,2,3,5-tetramethoxy-N-methylacridone, toddaliopsin C and the new seco acridone alkaloid inopinatin. The known quinoline alkaloids 2-phenyl-1-methyl-quinolin-4(1H)-one, 2-phenyl-1-methyl-7-methoxy-quinolin-4(1H)-one, dictamnine, and the coumarins scopoletin and marmesin were also isolated. The isolated compounds and the distribution of secondary metabolites, which are systematically important, obtained from literature, clearly confirmed that some species formerly described in the genera Angostura and Galipea in fact shall belong to the genus Conchocarpus.

This study identified the threshold concentration of limonoids for the complete inhibition of oviposition of Ceratitis capitata (Wiedemann) in grapes 'Itália.' Choice and no-choice experiments with the insect were performed. The three no-choice bioassays were conducted following a completely randomized design with 18 treatments (three densities of insects [one, two, or three females]×five concentrations of limonoids and control) and 20 replicates. In a free choice bioassay, two fruits per cage (a treatment grape and a control) were provided for ovipositing. Three densities of insects (one, two, or three females) were used, with 15 replicates. Bioassays were conducted at 25±2°C, 60±10% relative humidity, and a photoperiod of 14:10 (L:D) h. The inhibition of oviposition of C. capitata was concentration dependent, with infestation occurring at lower concentrations of azadirachtin (+3-tigloylazadirachtol) and complete inhibition occurring at concentrations at or exceeding 100 ppm azadirachtin (+28.5 ppm of 3-tigloylazadirachtol), maintaining protective effects even at the most densely populated treatment (three females per fruit). When the pest had a free choice of host grapes (treatment vs. control), severe inhibition was observed at concentrations≥50 ppm azadirachtin (+14.3 ppm of 3-tigloylazadirachtol). We conclude that a threshold concentration of 100 ppm azadirachtin (+28.5 ppm of 3-tigloylazadirachtol) is capable of preventing grape infestation. This concentration is likely to provide a reliable level of protection, as the experimental population density of three females per fruit usually does not occur in the field and wild flies usually have more host options.

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