Molecular characterization of two Chinese isolates of Beet western yellows virus infecting sugar beet.

Beet western yellows virus (BWYV) has previously been reported as an agent of sugar beet yellowing disease in China. In this article, the complete genomic RNA sequences of two Chinese BWYV isolates infecting beet from Inner Mongolia (BWYV-IM) and Gansu (BWYV-GS) were determined and compared with three beet poleroviruses (BMYV, BChV and BWYV-US) and other non-beet-infecting poleroviruses. The genomes of the two isolates were 5,668 nt in length, and had almost the same genomic organization and characteristics as BWYV-US.

[Production and releasing sites of superoxide anion in phytopathogenic bacteria].

Many phytopathogenic bacteria were founded to release the superoxide anion (O2-) by themselves from different sites and the production of O2- was related to the pathogenicity of strains. The presences of O2- in cytomembrane, cell wall and filtrate were confirmed by chemical method and electron spin resonance (ESR). The results show that filtrate may be the primary site of O2- production due to its higher O2- generating activity either in the presence or the absence of DDC.

[O2-* burst of tobacco leaves triggered by Erwinia carotovora subsp. carotovora inoculation].

O(-.)(2) production based on chemical method by Ecc-treated intact tobacco leaves was observed. It showed a long-lasting one-phase course beginning 1 h and ending 14 h after Erwinia carotovora subsp.

[Field test and lab experiment on control efficacy of the pathogen of opium poppy mildew].

Objective: To screen effectual fungicides for field control because of the seriousness of opium poppy mildew and importance of chemical control on plant diseases.

Method: Seven fungicides were screened in Lab experiment and field test during 1996-1997.

Result And Conclusion: All of them and their different dosages were effective to control conidia of Peronospora arborescens.