This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

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Neste estudo, desenvolvido na entressafra do arroz (Julho-Outubro) de 1995, no Projeto Rio Formoso, município de Formoso do Araguaia - TO, com o objetivo de verificar o comportamento da população das pragas e seus inimigos naturais em soja, foram realizados levantamentos semanais com o método do pano de batida, em três cultivares de soja de ciclo médio: EMGOPA 308, DOKO RC e EMBRAPA 31 (BR 81). Entre os percevejos fitófagos somente foi constatada a ocorrência de Piezodorus guildinii, com picos populacionais no período de enchimento de grãos, porém não atingindo o nível de controle. As lagartas desfolhadoras encontradas foram Anticarsia gemmatalis, Hedylepta indicata e Chrysodeixis íncludens, em ordem decrescente de abundância. Dos coleópteros desfolhadores, a espécie encontrada em maior abundância foi Cerotoma sp. com picos populacionais próximos ao período reprodutivo, diferindo significativamente entre as cultivares. Dentre os inimigos naturais, foi verificada a ocorrência, em maior abundância de Cycloneda sanguínea (Coleoptera, Coccinellidae), Geocoris sp. (Heteroptera, Lygaeidae) e Lebia sp. (Coleoptera, Carabidae).

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The authors aimed to evaluate the resistance to gummy stem blight and the agronomic traits of the melon crop in the Southern Region of the State of Tocantins, Brazil, in two growing seasons, submitted or not to treatment with fungicides. Two experiments were carried out: dry season (experiment I), and rainy season (experiment II), respectively, comprising the periods from July to October 2013 and from March to May 2014. Six melon cultivars were used in each season. In the dry season: Eldorado 300, Hibrix, Dourado Amarelo, Louro, Gaúcho Redondo and Canarian; and in the rainy season: Eldorado 300, Hibrix, HF-4439, Louro, Gaúcho Redondo and Canarian. Treatments consisted of each cultivar and split plot with (WA) or without fungicides application (NA). All cultivars were susceptible to disease, considering that Gaúcho Redondo was the least susceptible in the dry season. The fungicide application decreased disease severity in the dry season, however the productivity of the crop in treatments without fungicide application were not compromised, due to the late onset of the disease, and ranged from 19.2 t/ha for Eldorado 300 up to 41.9 t/ha for Canarian. The total soluble solids showed average values of 12°Brix, except for cultivar Gaúcho Redondo, which showed Brix value lower than commercial standards. During the rainy season, fungicide application did not protect the plants, which did not complete the cycle, resulting in the absence of marketable fruit production. The climatic characteristics observed in the rainy season, with high humidity, leaf wetness and high temperatures are favorable for the development of gummy stem blight in melon plants. Thus, in Tocantins, the dry season is characterized as the best time of year for cultivation, between April and September.