French J M, Heerema R J, Gordon E A, Goldberg N P
New Mexico State University, Department of Extension Plant Sciences, Las Cruces 88003.
New Mexico State University, Otero County Extension Service, Alamogordo 88310.
Plant Dis. 2009 Jul;93(7):762. doi: 10.1094/PDIS-93-7-0762C.
In September of 2008, a Septoria sp., the causal agent of Septoria leaf spot of pistachio (Pistacia vera L.) was isolated from leaf lesions in an orchard in southern New Mexico. Tree fruit and nut crops including pistachios are becoming an increasingly important part of New Mexico's agricultural industry with total cash receipts of $103 million in 2007 (3). This preliminary positive for Septoria prompted a survey of pistachio-growing counties in the state. The surveyed orchards accounted for approximately 30% of the pistachio acreage in New Mexico. Results indicated that all five pistachio-growing counties had orchards infected with a Septoria sp. Isolates of Septoria from leaf lesions were identified as Septoria pistaciarum Caracc. based on the following symptoms and morphological characteristics of the fungus: leaf lesions were usually circular, 0.5 to 3 mm in diameter, and contained many pycnidia per lesion; pycnidia were dark, ostiolate, and measured 101 to 255 × 69 to 133 μm; and conidia were hyaline, filiform, contained 3 to 9 septa, and measured 3 to 4 × 60 to 149 μm. Most orchards were only mildly affected. In severe cases, hundreds of leaf lesions were present on diseased leaves; large sections of the leaves turned tan and some trees defoliated prematurely. This widespread occurrence of Septoria leaf spot in New Mexico in 2008 suggests that the disease had already been present in the state for several years. A higher average rainfall in the summer of 2008 provided excellent conditions for disease development. Because of the high amounts of inoculum currently present in New Mexico orchards, Septoria leaf spot may emerge as a recurring disease problem for pistachio producers. This disease was first reported in the United States in Texas in 1971 and was also reported in Arizona in 1989 (1,2,4). To our knowledge, this is the first report of Septoria leaf spot of pistachio in New Mexico. References: (1) A. Chitzandis. Ann. Inst. Phytopathol. Benaki 10:29, 1956. (2) J. L. Maas et al. Plant Dis. Rep. 55:72, 1971. (3) New Mexico Agricultural Statistics, Department of Agriculture, 2007. (4) D. J. Young and T. Michailides. Plant Dis. 73:775, 1989.
2008年9月，从新墨西哥州南部一个果园的叶片病斑中分离出一种壳针孢菌，它是阿月浑子叶斑病（黄连木叶斑病）的病原体。包括阿月浑子在内的果树和坚果作物正日益成为新墨西哥州农业产业的重要组成部分，2007年的现金总收入为1.03亿美元（3）。这种对壳针孢菌的初步阳性检测结果促使对该州种植阿月浑子的县进行了一次调查。被调查的果园约占新墨西哥州阿月浑子种植面积的30%。结果表明，所有五个种植阿月浑子的县都有果园感染了一种壳针孢菌。根据该真菌的以下症状和形态特征，将从叶片病斑中分离出的壳针孢菌鉴定为黄连木壳针孢菌：叶片病斑通常为圆形，直径0.5至3毫米，每个病斑含有许多分生孢子器；分生孢子器颜色深，有孔口，大小为101至255×69至133微米；分生孢子无色透明，丝状，有3至9个隔膜，大小为3至4×60至149微米。大多数果园只是受到轻微影响。在严重的情况下，患病叶片上会出现数百个叶斑；叶片的大片区域变成黄褐色，一些树木过早落叶。2008年新墨西哥州阿月浑子叶斑病的广泛发生表明，这种病害在该州已经存在了数年。2008年夏季较高的平均降雨量为病害发展提供了极佳的条件。由于新墨西哥州果园目前存在大量接种体，阿月浑子叶斑病可能会成为阿月浑子种植者反复面临的病害问题。这种病害于1971年在美国得克萨斯州首次报道，1989年在亚利桑那州也有报道（1,2,4）。据我们所知，这是新墨西哥州阿月浑子叶斑病的首次报道。参考文献：（1）A. Chitzandis。《贝纳基植物病理学研究所年报》10:29，1956年。（2）J. L. Maas等人。《植物病害报告》55:72，1971年。（3）新墨西哥州农业统计局，2007年。（4）D. J. Young和T. Michailides。《植物病害》73:775，1989年。
