Abstract Carbonaceous porous materials are strong candidates for producing low-cost, lightweight, and sustainable electromagnetic (EM) absorbing materials. This work investigates the production of radar-absorbing materials (RAM) by a simple method. Sustainable carbon xerogel (CX) was synthesized from tannin, a biosourced molecule. CX and commercial carbon nanotube (CNT) were embedded in a silicone matrix at proportions of 10 and 15 wt.% of CX and 0.1 wt.% of CNT to produce flexible composites. The morphology and structure of the carbonaceous materials were evaluated by field-emission scanning electron microscopy (FEG-SEM), Raman spectroscopy, X-ray diffraction (XRD), textural properties by N2 adsorption-desorption isotherms, and mercury porosimetry. The electromagnetic characterization of the composites was analyzed by a vector network analyzer (VNA) in the Ku-band. The results demonstrated that an increased concentration of CX in the composite improved reflection loss reaching -43.19 dB at 13.79 GHz.

A lagarta-da-soja, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), é uma praga importante na cultura da soja no Brasil. Este estudo teve como objetivo avaliar diferentes inseticidas, reguladores de crescimento, para o controle dessa praga. Os inseticidas diflubenzuron (15g i.a. ha-1), lufenuron (7,5g i.a. ha-1), metoxifenozide (21,6g i.a. ha-1) e teflubenzuron (7,5g i.a. ha-1) foram aplicados com pulverizador costal de precisão, equipado com pontas tipo leque 110, 02, numa pressão de 1 bar e volume de calda de 100l ha-1. No dia da aplicação dos inseticidas, as plantas de soja (cv. Fundacep 33) estavam com 0,90m de altura, no estádio R3.1, e infestação média de 95 lagartas pequenas e de 33 lagartas grandes por dois metros de fileira. A eficiência dos inseticidas foi determinada através da contagem do número de lagartas vivas pequenas e grandes aos 0, 2, 4, 7 e 10 dias após a aplicação (DAA); da percentagem de desfolha aos 15 DAA e da produção de grãos. Foi observado efeito de choque do inseticida metoxifenozide tanto em lagartas pequenas quanto em grandes. Os inseticidas diflubenzuron, lufenuron e teflubenzuron controlaram eficientemente as lagartas a partir de 4 DAA. As infestações de lagartas nas parcelas testemunhas aumentaram a desfolha em 75,8% e reduziram produtividade para 2371 kg ha-1. Nas parcelas tratadas com inseticidas desfolha variou de 34,7% a 50,7% e a produtividade entre 3255kg ha-1 e 3585kg ha-1.

The velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is an important soybean pest in Brazil. This study aimed to evaluate growth regulators insecticides. A precision sprayer equipped with 110 02 nozzles, working at a constant pressure of 1 bar and volume of 100 liters per hectare was used to apply the insecticide treatments (diflubenzuron at 15g a.i. per hectare, lufenuron at 7.5 g a.i. per hectare, metoxyfenozide at 21.6g a.i. per hectare and teflubenzuron at 7.5g a.i. per hectare). Applications when plants were 0.90m height, in the R3.1 growth stage, and the number of small larvae was 95, while that of large larvae was 33 per two meters of row. The number of live larvae at 0, 2, 4, 7 and 10 days after application, the defoliation at 15 days after application and grain yield were evaluated. The fastest control of large and small larvae was obtained with metoxyfenozide at 2 days after application. The insecticides diflubenzuron, lufenuron and teflubenzuron efficiently controlled of large and small larvae, but only at 4 days after application. Larval infestations in non-treated plots resulted in significant defoliation and yield losses when compared to plots treated with insecticides.

A larva de Diloboderus abderus Sturm (Coleoptera: Melolonthidae) é uma praga importante da cultura do trigo (Triticum aestivum L.) em plantio direto na região Sul do Brasil. Este estudo teve como objetivo avaliar diferentes inseticidas aplicados nas sementes (fipronil e tiametoxam) e via pulverização do solo (clorpirifós e lambdacialotrina) para o controle dessa praga. A eficiência dos inseticidas foi determinada através do número de larvas vivas no solo aos 30, 60 e 90 dias após a emergência das plantas (DAE), da massa seca da parte aérea das plantas aos 90 DAE e da produção de grãos. Foram observadas correlações negativas significativas entre a dose dos inseticidas fipronil e tiametoxam e o número de larvas, e correlações positivas significativas entre estes inseticidas e a massa seca da parte aérea e a produtividade de grãos. Infestações de larvas nas testemunhas não tratadas reduziram a produtividade em relação às áreas tratadas com inseticidas. A produtividade incrementou à medida que aumentou a eficiência de controle do inseto pelos inseticidas. Concluiu-se que clorpirifós (960 e 1200g i.a./ha) e lambdacialotrina a 25g i.a./ha (formulação CE), aplicados em pulverização do solo, são eficientes para reduzir a população de larvas de D. abderus, garantindo a produtividade de grãos. Sugerem-se novos testes com os inseticidas fipronil, tiametoxam e lambdacialotrina (formulação SC) para determinar doses técnica e economicamente adequadas para o controle de larvas de D. abderus em trigo.

The larva of Diloboderus abderus Sturm (Coleoptera: Melolonthidae) is an important wheat (Triticum aestivum L.) pest under no-till system in the Southern region of Brazil. This study aimed to evaluate insecticides applied as seed treatment (fipronil and thiamethoxam) and in soil pulverization (chlorpyriphos and lambdacyhalothrin). The effectiveness of the insecticides were assessed by determining the number of larvae in the soil at 30, 60 and 90 days after emergence, the plant biomass at 90 days after emergence and the grain yield. Significant negative correlations were obtained between doses of fipronil and thiamethoxam with number of larvae. Significant positive correlations were observed between doses of fipronil and thiamethoxam with plant biomass and grain yield. Larvae infestations in non-treated plots caused significant yield losses when compared to plots treated with insecticides. Increasing control of larvae with insecticides increased the crop yield. It is concluded that chlorpyriphos (960 and 1200g a.i./ha) and lambdacyhalothrin a 25g i.a./ha (EC formulation), in soil pulverization, were efficient in reducing larval population and maintaining grain yields. Additional studies with thiamethoxam, fipronil and lambdacyhalothrin (CS formulation) are suggested to determine most efficient technical and economical dosages of these products to control D. abderus larvae in wheat.