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721.
M. A. Macedo T. M. Costa J. C. Barbosa J. L. Pereira M. Michereff‐Filho R. L. Gilbertson A. K. Inoue‐Nagata A. Bergamin Filho 《Plant pathology》2017,66(4):529-538
Over the last two decades, begomovirus diseases have increased in importance in Brazilian tomato crops. The major management strategy in Brazil is the application of insecticides to control the whitefly vector, but this is often unsuccessful. The objective of this work was to study the spatial and temporal progression of the disease in two processing tomato production areas in Central Brazil. A total of 24 plots (225 plants each) in six fields were evaluated weekly by visual inspection for plants with begomovirus symptoms. The predominant begomovirus in tomato plants with symptoms was Tomato severe rugose virus, and it was also detected in weeds and other crop plants. No correlation between incidence of begomovirus disease and whitefly population was found. The disease progression was rapid, with a slightly aggregated distribution of plants with symptoms. No relevant differences were observed in the temporal and spatial analyses, although an important difference was detected between plots located at the centre (PC) and the edge (PE) of the fields. In the temporal analysis, the begomovirus incidence and area under disease progress curve values were lower in PC than in PE. In the spatial analysis, plants with begomovirus symptoms were more aggregated in PC than in PE. These results suggest that the distribution of plants with symptoms in PC and PE could be a result of three dissemination mechanisms: one random (primary) and two aggregated, a real secondary spread, and a false secondary spread. The implications of these differences on disease management are discussed. 相似文献
722.
Hirofumi Nagai Noriyuki Miyake Shinro Kato Daisuke Maekawa Yasuhiro Inoue Yuichi Takikawa 《Journal of General Plant Pathology》2017,83(6):373-381
We examined the potential for biological control of black rot of broccoli, caused by Xanthomonas campestris pv. campestris (Xcc), using nonpathogenic Xanthomonas sp. strain 11-100-01 (npX) mixed with bacteriophage XcpSFC211 (pXS). Inoculation of intact broccoli plants in greenhouse trials with either npX or pXS did not control black rot. After injured plant inoculation, however, npX alone or npX with pXS significantly controlled black rot. When a mixed suspension of npX with pXS was placed on a membrane filter, then washed with distilled water and air-dried, a substantial amount of pXS adsorbed to the surface of npX. In a field trial, broccoli plants were sprayed with a suspension of npX with pXS, then inoculated with Xcc. A meta-analysis of the results from five field trials showed an integrated risk ratio (IRR, the ratio of disease incidence in inoculated broccoli plants to the incidence in control plants) of 0.69 after treatment with only npX and 0.59 with npX with pXS, indicating that black rot incidence was significantly reduced by each treatment. The difference between these two treatments was also significant. IRR was 1.24 when comparing suppression by npX with pXS and that by basic copper sulfate wettable powder; thus, their control was comparable. The combination of npX with pXS improved the preventive effect against black rot. This is the first report describing that a nonpathogenic Xanthomonas sp. strain mixed with a bacteriophage effectively controlled black rot of broccoli in field trials. 相似文献
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