Crescimento e produção do jambu submetido a lâminas de irrigação

This study evaluated the effect that different irrigation depths have on the growth and crop production of jambu plants. The treatments consisted of five irrigation depths corresponding to 40%, 70%, 100%, 130% and 160% of field capacity. We used randomized blocks with four replications for the experimental design. The plot consisted of four plants in separate pots. For comparison of treatments, at 27 days after transplantation, the following variables were analyzed: plant height, stem diameter, leaf fresh matter, stalk fresh matter, root fresh matter, inflorescence fresh matter, leaf dry matter, stalk dry matter, root dry matter, inflorescence dry matter and water use efficiency. The effect of irrigation depth was significant for the analyzed variables, except for stem diameter and inflorescence dry matter. There was a quadratic behavior of the variables regarding the applied irrigation depths. The maximum values of each parameter were obtained with irrigation depths close to 100% field capacity. Although the efficiency of water use was higher for the irrigation depth of 40% field capacity, the use of irrigation depth at 100% field capacity is recommended since it provided the best answers of the variables analyzed.

Efeito de inibidores de proteases na atividade enzimática de Coccus viridis em Coffea arabica

A cultura do café no Brasil tem muita importância econômica e relevância no setor social. É possível que as injurias causadas pelo inseto Coccus viridis (cochonilha-verde) seja um dos motivos da redução de sua produtividade. As plantas, ao serem injuriadas, são capazes de aumentar a síntese de inibidores de proteases (IPs) por toda sua extensão. Estudos demonstraram que insetos alimentados com plantas previamente pulverizadas com inibidores sintéticos têm seu desenvolvimento afetado. Assim, este trabalho teve por objetivo avaliar os efeitos dos inibidores de proteases sintéticos, benzamidina e berenil, sobre a atividade proteolítica intestinal de C. viridis. Plantas de Coffea arabica foram infestadas com ninfas de C. viridis e pulverizadas com benzamidina e berenil, em quatro diferentes concentrações: 0; 0,25%; 0,5% e 0,75% (p/v). A resposta bioquímica do inseto foi avaliada após 24 horas da pulverização, coletando-se os insetos. A atividade das serino-proteases tripsina-like (amidásica e esterásica) e quimotripsina-like esterásica foi reduzida pela presença dos inibidores. O mesmo se obteve em relação à atividade das cisteíno-proteases.

Avaliação das propriedades do bagaço de cana e bambu para produção de celulose e papel

The raw materials commonly used to produce pulp and paper in Brazil are woods from planted forests. Although with tremendous potential, the use of non-wood fibers is inexpressive. This study thus aimed to evaluate the use of sugarcane bagasse and bamboo to produce pulp and paper via physical, chemical and anatomical characterization, and to verify the influence of its properties on the process and the final product. Anatomical analysis of the fibers was performed (length and width from fibers and vessels, lumen width and cell wall thickness), as well as chemical component analysis (cellulose, hemicellulose, lignin, extractives and ash) and basic density of the materials. Moreover, felting rate, Runkel, Mulsteph and Boiler indexes, flexibility coefficient and wall fraction were generated. Results showed that both materials differed statistically in chemical properties, except for lignin content; density and anatomical properties, excluding vessel width and felting rate. Bamboo presented higher values cellulose (52.96%), minerals (2.34%), density (0.461 g/ cm³), wall fraction (67.84%) and Runkel (2.11), Mulsteph (0.90) and Boiler indices (0.81) values, whereas sugarcane bagasse presented higher hemicellulose (17.63%), extractives (12.81%) and flexibility coefficient (46.19%) values. Most properties were similar to those observed in raw materials commonly used for this purpose. Therefore, these two materials have potential for use in the pulp and paper industries.

Efficacy and toxicity of insecticides to green peach aphid

Outbreaks of Myzus persicae (Sulzer) (Hemiptera: Aphididae) populations are not rare in Brassica crops in Pernambuco State (Brazil). The aim of the present study was to perform laboratory assessments in seven insecticide formulations against M. persicae. The direct spray and leaf dip methods were used in the experiment. M. persicae mortality rates were subjected to variance and Probit analyses. Based on the results, thiamethoxam + lambdacyhalothrin, thiamethoxam, lambda-cyhalothrin and thiamethoxam + chlorantraniliprole were the most efficient insecticides after 24-hour exposure, since they caused over 95% mortality through the direct spray method. LC50s ranged from 0.10 to 9.1 mg a.i./L in chlorfenapyr and chlorantraniliprole, respectively, in the leaf dip method. All insecticides were effective against M. persicae, except for chlorantraniliprole. Chlorfenapyr, lambda-cyhalothrin, pymetrozine and thiamethoxam + lambda-cyhalothrin were the most toxic to this aphid.

Qualidade pós-colheita de tubérculos de batata ‘Ágata’ embalados armazenados em diferentes condições

The adequate storage of raw materials is fundamental to obtain a quality final product. The objective of this study was to evaluate the effect of different plastic packages on the maintenance of post-harvest quality of ‘Agata’ potato tubers stored under refrigeration and room temperature. Two experiments were conducted, both with a completely randomized design, arranged in a 3 x 4 factorial scheme (three types of packages – unpacked, with polyvinyl chloride film – PVC (21 cm x 40 cm and 12 μm thick) and with plastic bag (30 cm x 40 cm and 30 μm thick) and four evaluation times), with three replicates of one tuber each. In one experiment the samples were maintained under ambient conditions (25 ± 2°C and 60% ± 5% RH), with evaluations performed at 0, 7, 14 and 21 days, and another under refrigeration (8 ± 2ºC 75% ± 2% RH) and 0, 25, 50 and 75 days. The evaluated characteristics were: firmness, pH, soluble solids, total titratable acidity, vitamin C and the appearance of shoots. Tubers can only be stored under ambient conditions for seven days, and during this period the PVC packaging is the most suitable for storage. Tuber firmness was reduced and the vitamin C content of the last evaluation was higher than the initial content in both storage conditions. The refrigerated storage extended the shelf life of tubers for up to 50 days, period during which the PVC and plastic bags did not influence the conservation of the ‘Agata’ potato tubers.