Henríquez N P, Kenyon L, Quiroz L
Centro Nacional de Tecnología Agropecuaria, Apdo Postal 885, San Salvador, El Salvador.
Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB UK.
Plant Dis. 1999 Jan;83(1):77. doi: 10.1094/PDIS.1999.83.1.77B.
Successive plantings of sweet corn in Orange Walk District, Belize (<200 m ASL) were observed to be performing poorly. Plants were stunted with shortened upper internodes, over-production (proliferation) of ears, and chlorosis of ears and leaf bases. Plants of hybrid white corn in Cayo District (<200 m ASL) had leaf-base chlorosis, mid-vein reddening, chlorotic bands on the leaves, and die-back of leaf tips: symptoms attributed to infection by the corn stunt complex (CSC) pathogens. Spiroplasma kunkelii was detected in symptom-bearing leaf-base samples of white corn but not sweet corn, using a specific F(ab') protein-A enzyme-linked immunosorbent assay (ELISA; D. Gordon, Ohio). Polymerase chain reactions with maize bushy stunt (MBS) phytoplasma-specific primers (1) resulted in amplification products of the expected size (740 bp) when DNA extracts from either sample type were used as template. DNAs from apparently healthy sweet or white corn from the field, or from glasshouse-grown sweet corn, did not yield this product. MBS and S. kunkelii are transmitted by leafhoppers of the genus Dalbulus, often simultaneously with maize rayado fino virus, the other CSC component (not tested for in this study). All the sweet corn varieties examined had a high incidence of the symptoms, suggesting that they are highly susceptible to one or both of the CSC mollicutes. With the increase in area dedicated to maize production and successive year-round plantings, the potential for spread and increased incidence of MBS or CSC in Belize is considerable. Reference: (1) N. A. Harrison et al. Plant Dis. 80:263, 1996.
在伯利兹奥兰治沃克区（海拔<200米）连续种植的甜玉米生长状况不佳。植株发育不良，上部节间缩短，果穗过度生长（增殖），果穗和叶基部出现黄化。凯约区（海拔<200米）的杂交白玉米植株出现叶基部黄化、叶脉中部发红、叶片上有黄化条带以及叶尖枯死：这些症状归因于玉米矮化复合症（CSC）病原体的感染。使用特定的F(ab')蛋白A酶联免疫吸附测定法（ELISA；俄亥俄州的D. 戈登），在有症状的白玉米叶基部样本中检测到了昆氏螺原体，但在甜玉米中未检测到。当使用两种样本类型的DNA提取物作为模板时，用玉米矮化植原体特异性引物（1）进行聚合酶链反应，得到了预期大小（740 bp）的扩增产物。来自田间明显健康的甜玉米或白玉米，或温室种植的甜玉米的DNA，均未产生此产物。MBS和昆氏螺原体由Dalbulus属叶蝉传播，通常与玉米雷亚多菲诺病毒同时传播，玉米雷亚多菲诺病毒是CSC的另一个组成部分（本研究未对此进行检测）。所有检测的甜玉米品种症状发生率都很高，这表明它们对CSC支原体中的一种或两种高度敏感。随着玉米种植面积的增加和全年连续种植，MBS或CSC在伯利兹传播和发病率增加的可能性很大。参考文献：（1）N. A. 哈里森等人，《植物病害》80:263，1996年。
