Biological cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae) on leaflets of three rubber tree clones

Life cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae) on leaflets from three rubber tree clones. The biological cycle of Tenuipalpus heveae Baker, 1945 (Tenuipalpidae), a potential rubber tree pest mite, was studied by the observation of individuals reared on leaflets of the clones GT 1, PB 235 and RRIM 600, in controlled environmental conditions. Three daily observations were done of 60 eggs on leaflets from each clone in order to verify the development of immature stages and the female oviposition. The fertility life table was constructed based in the collected data. Mites reared on PB 235 had faster rate of development, requiring less time in days, to double its population in number (TD), and had the highest values for egg production, female longevity, net reproductive rate (Ro), intrinsic rate of natural increase (r m) and finite rate of increase (λ). Lower reproductive values and the longest time necessary to reach adult stage were recorded for the mites on GT 1. In all studied clones, the deutonymphal phase had the highest viability, while the larval phase had the lowest, highlighted by the survivorship curve that indicated high mortality during this life stage. The clone PB 235 allowed the most suitable conditions for the development of T. heveae, followed by RRIM 600, while GT 1 was the less suitable substratum to rear this mite species.

Occurrence of weeds in Cassava savanna plantations in Roraima

A phyto-sociological survey is the first step to implement integrated weed management in crops. In this study, weed occurrence was evaluated in cassava plantations in the savannah of Roraima in northern Brazil. Harvest was performed randomly 80 times in 10 crops over four seasons (January, February, March, and April 2012). The harvested plants were cut at ground level, sorted out per species, identified, quantified, and weighed on a 0.01 g precision scale. A descriptive analysis was conducted of the phyto-sociological parameters (frequency, density, abundance, total number of individuals per species, relative frequency, relative density, relative abundance and importance value index) for the collected species. A description was also made of the botanical classes, families, species, type of propagation, life cycle, growth habit, total number of species and dry weight ha-1. The community in the surveyed area was considered to have a heterogeneous composition, comprising 27 species. The species presenting the highest density per hectare were Digitaria sanguinalis (210,500), Brachiaria brizantha (111,000), Brachiaria decumbens (86,500) and Brachiaria humidicola (69,000). Digitaria sanguinalis had the highest relative density (28.08), relative abundance (26.16) and importance value index (65,34). Most weeds had herbaceous growth habit.

Assessing environmental impacts using a comparative LCA of industrial and artisanal production processes: "Minas Cheese" case

This study uses the Life Cycle Assessment (LCA) methodology to evaluate and compare the environmental impacts caused by both the artisanal and the industrial manufacturing processes of "Minas cheese". This is a traditional cheese produced in the state of Minas Gerais (Brazil), and it is considered a "cultural patrimony" in the country. The high participation of artisanal producers in the market justifies this research, and this analysis can help the identification of opportunities to improve the environmental performance of several stages of the production system. The environmental impacts caused were also assessed and compared. The functional unit adopted was 1 kilogram (Kg) of cheese. The system boundaries considered were the production process, conservation of product (before sale), and transport to consumer market. The milk production process was considered similar in both cases, and therefore it was not included in the assessment. The data were collected through interviews with the producers, observation, and a literature review; they were ordered and processed using the SimaPro 7 LCA software. According to the impact categories analyzed, the artisanal production exerted lower environmental impacts. This can be justified mainly because the industrial process includes the pasteurization stage, which uses dry wood as an energy source and refrigeration.