Abstract Background There is little information on how different soil cover systems influence the residual effect of pre-emergent herbicides used in soybean cultivation in Brazil. Objective The objective was to compare the persistence of different pre-emergent herbicides in a Latosolic Dystrophic Red Nitosol soil in the presence or absence of black oat straw on the soil surface. Methods The herbicides used were chlorimuron-ethyl (40.0 g ai ha-1), diclosulam (70.1 g ai ha-1), flumioxazin (100.0 ai g ha-1) and saflufenacil (70.0 g ai ha-1). Soil samples were collected at 0, 5, 10, 15, 20, 32, 46 and 60 days after herbicide application. The bioavailability of the herbicides was evaluated in a greenhouse using cucumber plants as bioindicators. Results Rainfall was necessary for the herbicides to go through the straw layer and reach the soil. Using straw, the half-life times for chlorimuron, diclosulam, flumioxazin and saflufenacil were 42, 61, 49 and 26 days, while without straw, they were 23, 45, 8 and 10 days, respectively. Conclusion The presence of straw on the soil surface increased the persistence of herbicides in the soil.

Anastrepha fraterculus (Wiedemann) is the main species of frugivorous insect that damages berries of table grape (Vitis vinifera L.) in Southern Brazil. This study was conducted to isolate and identify the fungi associated with bunch rot present in the body of adults of A. fraterculus collected in a commercial vineyard. From January to February 2011, adults of A. fraterculus were collected from a commercial vineyard of green grapes using adapted McPhail traps. In laboratory, flies bodies were divided into four parts (head, legs, wings, and ovipositor) in Petri dishes with PDA medium to evaluate microorganisms associated. Six adult females of A. fraterculus collected in the field were also analyzed in a scanning electron microscope (SEM) to identify spores of fungi. Phytopathogenic microorganisms were found in all sectioned parts. Fungal spores were recorded adhered to the body of adult females of A. fraterculus. The main species of fungi found in the body parts of A. fraterculus were Cladosporium spp. (20.2% of the obtained colonies), Botrytis cinerea Pers. (12.9%), Colletotrichum spp. (10.1%), Penicillium spp. (10.1%), Fusarium spp. (7.7%), followed by Rhizopus spp., Trichoderma spp. and Aspergillus spp., suggesting that the insect can serve as a mechanical vector of spores increasing damage in the vineyards.

O presente trabalho analisa a evolução histórica dos preços pagos ao produtor dos principais produtos pecuários do Rio Grande do Sul nas últimas três décadas, dando especial atenção às tendências ocorridas a partir da década de 90 e, principalmente, após a estabilização monetária obtida com o Plano Real de 1994. A pesquisa foi realizada com base no histórico de preços médios mensais pagos ao produtor, coletados pela Emater/RS, abrangendo o período de janeiro de 1973 a dezembro de 2004. A análise permitiu concluir que todos os produtos pesquisados (carnes bovina, ovina, suína e de frango, ovos e leite) apresentaram uma desvalorização significativa em seus preços reais entre os anos de 1973 e 2004, com tendência declinante até 1994, sendo que o período entre o início da década de 80 e meados da década de 90 foi o de maior declínio nos preços. Além disso, concluiu-se que o período pós-Plano Real foi marcado por uma estabilização dos preços reais da maioria dos produtos analisados, exceto dos preços de produtos da ovinocultura, que apresentaram tendência de elevação no período.

This work analyses the historical evolution of prices paid to farmers of main animal derived products from the state of Rio Grande do Sul for the last three decades, emphasizing tendencies that occurred since the 90s, and mainly after the monetary stabilization obtained in 1994 with the "Plano Real". This study was based on records of median monthly prices paid to the farmer, collected by Emater/RS, considering the period since January 1973 until December 2004. The analysis concluded that all of the products considered (beef cattle, sheep and pork meat, poultry, eggs and milk) presented a significant decrease in their real price value between 1973 and 2004, with decreasing tendency up to 1994, being that the period between the beginning of the 80s and midst 90s was the one with the highest decrease in prices. Furthermore, it was concluded that the period after the "Plano Real" was characterized by real price stabilization in most of the studied products, except sheep derived products, which presented a tendency to increase prices during this period.