Use of essential oils from plants of Araripe National Forest against Aedes aegypti (Diptera: Culicidae).

Aedes aegypti control is achieved with chemical insecticides that can promote insecticide resistance. In the search for new forms of control, the use of botanical products is currently growing and many tests with oils have already been performed. The plant diversity of Araripe National Forest enables the study of several species against this vector. To evaluate the larvicidal effect of essential oils from plants of this forest, we used field rosemary, copaiba, bay leaf, cashew and pequi. The work was divided into three stages: all oils with the same dosage; the best oil at dosages of 0, 5, 10, 20, 50 and 75 µg/mL; and the best dosage at temperatures of 15, 20, 25, 30 and 35 °C. The oils of field rosemary, copaiba, bay leaf, cashew and pequi were good insecticides when used at dosages above 5 µg/mL. The bay leaf oil showed high larvicidal activity at all dosages tested, showing the highest efficiency at 75 µg/mL. Temperatures of 15 and 35 °C increased the susceptibility of the insect to the effect of the bay leaf oil. The essential oils of field rosemary, copaiba, bay leaf, cashew and pequi, from Araripe National Forest, applied at a dosage of 5µg/mL, showed insecticidal action, although with low efficiency.

Phytochemical prospection, hemagglutinating and insecticidal activity of saline extracts from the seeds of Tamboril (Enterolobium contortisiliquum) Vell. Morong (Fabaceae) on Aedes aegypti (Diptera: Culicidae).

This study evaluated the insecticidal activity of crude extracts from Enterolobium contortisiliquum (Vell.) seeds on eggs and larvae of A. aegypti, and also verified the phytochemical profile and the presence of lectins in the extract. The 0.15 M NaCl saline solution was used as the extracting substance. For tests with eggs and larvae, the crude extract was used in its raw form (RCE) and boiled at 100º C for 5 min (BCE). Concentrations of 4.68; 9.37; 18.75; 28.13; 37.13 and 46.89 mg/mL, with distilled water as a negative control. Assays were performed in triplicate. The results were subjected to analysis of variance, Tukey's test and Log-Probit analysis to determine LC50 and LC90. BCE showed better results on eggs than RCE, managing to prevent the hatching of larvae in 81.66% ± 10.40 of treated eggs, at a concentration of 46.89 mg/mL. The LC50 and LC90 were set at 35.95 and 52.67 mg/mL, respectively. In tests with larvae, concentrations of 46.89 and 37.13 mg/mL, for RCE and BCE, caused 100% mortality in 24 hours of exposure. Larval mortality at the other concentrations increased with exposure time extending to 48 h. RCE, at 48 h exposure is the most promising extract on larvae (E = 72.77%, LC90 = 10.86 mg/mL). In RCE, the presence of lectins and secondary metabolites: flavonoids, xanthones and phenols, were detected. The results demonstrate the potential of E. contortisiliquum seed extracts with ovicidal and larvicidal action on A. aegypti.

Efficiency of essential oils in the control of the black bean aphid Aphis craccivora Koch (Hemiptera: Aphididae).

The black aphid Aphis craccivora Koch is one of the main pests of the caupi-bean crop Vigna unguiculata (L.) Walp. Due to the need to find effective and safe methods of control, there has been an increase in research seeking natural alternatives. Thus, the objective of this work was to evaluate the potential of essential oils from jatoba Hymenaea courbaril, copaiba Copaifera langsdorffii and aroeira Schinus terebinthifolius to control nymphs and adults of A. craccivora. The oils were extracted from the leaves by the hydrodistillation method, diluted to 0.1% in distilled water with 2% dimethyl sulfoxide (DMSO). Each treatment had four repetitions, plus a control with distilled water + 2% DMSO. The biotests were conducted in two stages: the first was conducted in the laboratory, under controlled conditions of temperature, relative humidity and photophase, and the second was conducted in the greenhouse, using only the treatment with the best laboratory test results. After 24, 48, 72, 96 and 120 hours of exposure, the insect mortalities were checked. In the first phase of the experiment, the aroeira oil showed 83.33% and 75.75% efficiency of mortality in nymphs and adults, respectively. In the greenhouse tests, this same oil showed 73.52% in nymphs and 62.85% in adults, opening new perspectives regarding its use as a natural insecticide for the control of the black aphid of the bean.

Phytochemical prospection and larvicidal bioactivity of the janaguba (Himatanthus drasticus) Mart. Plumel (Apocynaceae) latex against Aedes aegypti L. (Diptera: Culicidae).

The aim of this study was to carry out phytochemical prospecting and evaluate the larvicidal activity of Himatanthus drasticus latex extracts against Aedes aegypti. The extracts were obtained by maceration from 5 g of latex powder concentrated separately in 100 mL of methanol, ethyl acetate, and hexane solvents. The concentrations of 100, 200, 300, 400, and 500 ppm of each extract were tested in triplicate with a solution of pyriproxyfen as the positive control and distilled water and dimethylsulfoxide as the negative control. The phytochemical prospection of the methanolic extract showed the presence of phenolic compounds, such as anthocyanins, anthocyanidins, catechins, chalcones, aurones, leucoanthocyanidins, and condensed tannins. The insecticidal bioactivity was most significant for the methanolic extract. The methanolic extract lethal concentrations (LC) of 50 and 90% were 190.76 and 464.74 ppm, respectively. After 48 hours of exposure, the extracts using methanol, ethyl acetate, and hexane at their highest concentrations (500 ppm) caused larval mortality of 100, 73.33, and 66.67%, respectively. These extracts also promoted changes in the external morphology of the larvae, such as damage to the anal papillae, darkening of the body, and reduction in the number of bristles. The methanolic extract showed greater expressivity for morphological changes. The latex of H. drasticus has larvicidal activity against third-stade larvae of A. aegypti and it is more significant when obtained through maceration in methanol. The methanolic extract of H. drasticus latex contains phenolic compounds with insecticidal activity against A. aegypti larvae.

Análise faunística e flutuação populacional de moscas-das-frutas (Diptera: Tephritidae) em pomares comerciais de goiaba na região do Cariri cearense / Faunistic and populational analysis of fruit flies (Diptera: Tephritidae) in commercial guava orchards in the Cariri region (State of Ceará), Brazil

Devido à importância das moscas-das-frutas como pragas da fruticultura, este trabalho teve como objetivos caracterizar as populações das moscas-das-frutas em pomares comerciais de goiaba na região do Cariri, Estado do Ceará, por meio de índices faunísticos e estudar a flutuação populacional dessas moscas ao longo do ano. Para isso, foram instaladas armadilhas McPhail nos Municípios de Barbalha, Crato e Juazeiro do Norte. As armadilhas foram examinadas semanalmente e as moscas capturadas foram triadas, conservadas em álcool a 70% e identificadas. Constatou-se que Anastrepha zenildae (Wiedemann), A. sororcula Zucchi, A. fraterculus (Wiedemann), A. obliqua (Macquart) e Ceratitis capitata (Wiedemann) foram as moscas-das-frutas associadas à goiaba. Dessas, A. zenildae. A. sororcula e A. obliqua foram dominantes e constantes na região estudada, enquanto que A. fraterculus e C. capitata foram não-dominantes, mas também constantes. A. zenildae ocorreu em quase todos os meses do ano, exceto em outubro e dezembro de 2008, nos três pomares de goiaba do Cariri e com picos populacionais nos meses mais chuvosos e com temperaturas amenas.

Due to the importance of fruit-flies as pests in fruit growing, the present study was aimed to characterize the populations of fruit-flies in commercial guava orchards in the Cariri region (state of Ceará), Brazil, by means of faunistic indexes and to study their population fluctuation during the year. For this purpose, McPhail traps were installed in the counties Barbalha, Crato and Juazeiro do Norte. The traps were examined weekly and the captured flies were separated, preserved in 70% alcohol and identified. Anastrepha zenildae (Wiedemann), A. sororcula Zucchi, A. fraterculus (Wiedemann), A. obliqua (Macquart) and Ceratitis capitata (Wiedemann) were associated with guava fruits. Of them, A. zenildae. A. sororcula and A. obliqua were dominant and constant in the studied region, while A. fraterculus and C. capitata were non-dominant but constant. A. zenildae occurred in almost all months of the year, except October and December of 2008, with population peaks in the rainy season with its milder temperatures.