The spatial extent of tephra deposition and environmental impacts from the 1912 Novarupta eruption

The eruption of Novarupta within the Katmai Volcanic Cluster, south-west Alaska, in June 1912 was the most voluminous eruption of the twentieth century but the distal distribution of tephra deposition is inadequately quantified. We present new syntheses of published tephrostratigraphic studies and a large quantity of previously un-investigated historical records. For the first time, we apply a geostatistical technique, indicator kriging, to integrate and interpolate such data. Our results show evidence for tephra deposition across much of Alaska, Yukon, the northern Pacific, western British Columbia and northwestern Washington. The most distal tephra deposition was observed around 2,500 km downwind from the volcano. Associated with tephra deposition are many accounts of acid deposition and consequent impacts on vegetation and human health. Kriging offers several advantages as a means to integrate and present such data. Future eruptions of a scale similar to the 1912 event have the potential to cause widespread disruption. Historical records of tephra deposition extend far beyond the limit of deposition constrained by tephrostratigraphic records. The distal portion of tephra fallout deposits is rarely adequately mapped by tephrostratigraphy alone; contemporaneous reports of fallout can provide important constraints on the extent of impacts following large explosive eruptions

Variabilidade de Xanthomonas malvacearum (E. F. Smith) Dowson, no estado de São Paulo

No presente trabalho foi determinada a variabilidade de X. malvacearum, em condições de casa de vegetação, baseando-se na reação dos hospedeiros diferenciais para raças fisiológicas do patógeno. A técnica de inoculação empregada foi a de riscos feitos na página inferior das folhas e para avaliação dos sintomas foi adotada uma escala que variou de 1 a 5. Foi detectada a ocorrência das raças fisiológicas 3, 8 e 10. A linhagem do algodoeiro IAC RM3-4133 71/523 foi resistente à raça fisiológica 3, enquanto que as linhagens (Acala x Nu.16) 71/213 e IAC 12-2 71/170 foram resistentes às raças 3, 8 e 10.The variability of X. malvacearum was studied under greenhouse conditions with isolates obtained from the principal cotton growing regions of the State of São Paulo. The isolates were introduced into the tissues by scratching the under side of the leaves with a bamboo pick previously dipped in a bacterial suspension. For the evaluation of the symptoms a scale based on five infection types was used. As a result of these tests, the isolates were grouped into three races of X. malvacearum respectively races 3,8 and 10. The IAC RM3 71/523 line showed resistence to race 3, while (Acala x Nu-16) 71/213 and IAC 12-2 71/170 lines showed resistence to races 3,8 and 10. The susceptible cotton varieties IAC RM3, IAC 13-1 and IAC 12-2, cultivated in São Paulo State, reacted equally to the three races mentioned