Exserohilum rostratum對玉米及玉米田中雜草的病原性
Other Title
Pathogenicity of Exserohilum rostratum on corn and weeds in the corn fields.
Journal
植物病理學會刊
Journal Volume
10
Journal Issue
4
Pages
181-186
Date Issued
2001-12
Author(s)
Abstract
Exserohilum rostratum引起玉米葉斑病，在台灣為新紀錄，於1992年首次被發現。病原菌主要危害玉米葉片，初期呈針點水侵狀小點，繼續擴大後成橢圓形或不規則形，顏色為灰褐色或暗褐色，大小約為0.6-4.0 x 0.6-0.2mm。在oat meal agar(OMA)培養基上菌落呈擴展生長，暗灰色或黑色；菌絲有隔膜(septate)，寬為3.4-8.0μm；分生孢子柄(conidiophore)直立或彎曲狀，有隔膜，頂端常呈腫大膝狀彎曲，大小139.0-513.5 x 7.2-11.1μm；產孢細胞(conidiogenous cells)為合軸(sympodial)方式產孢；分生孢子(conidia)為橢圓形、棍棒狀或圓柱形，直立或彎曲形，具有2-11個離壁隔膜(distoseptate)，呈橄欖色或灰褐色，大小26.4-98.4 x 14.0-25.6μm。菌絲在4°C以下不生長，8-40°C皆能生長，而以28-32°C為最適生長溫度。接種8個玉米品種（哈蜜236、興農2號、蜜玉、神農1號、台南5號、台南17號、台農1號及台農351）均呈感病性，且罹病病斑面積率均相當高，均在50%以上。禾本科作物（甘蔗、高梁及小麥）及13種玉米田之雜草（蒺藜草、小葉灰藋、竹節草、狗牙根、香附子、馬唐、紫果馬唐、芒稷、牛筋草、大黍、鋪地黍、雙穗雀稗及龍葵等），僅龍葵不會被感染，其餘皆感病。
Leaf spot disease of com caused by Exserohilum rostratum (Drechsler) Leonard & Suggs was found on com (zea mays) leaves in Taiwan recently. The disease appeared as small (0.6-4.0 x 0.6-0.2 mm), grayish brown or dark grayish brown spots on Infected leaves. Colonies on oat meal agar at 25°C were effuse, dark gray or black. Mycelia were mostly immersed, septate and 3.4-8.0μm wide. Conidiophores (139.0-513.5 x 7.2-11.1μm) were straight to curved or flexuous, septate, and often moderately swollen and geniculate near the apex,. Conidiogenous cells were polytretic, and sympodial. Conidia were elongated-ellipsoidal to clavate or cylindrical, straight or curved, 2-11 distoseptate, and olive to grayish brown. The optimal temperatures for the growth of E. rostratum was from 28-32°C, while very slow growth was observed at temperature 8-40°C. E. rostratum infected leaves of Honey 236, Hsing-nung 2, Me-yu, Shung-nung 1, Tainan 5, Tainan 17, Tainung 1 and Tainung 351 of corn varieties:Pathogenicity tests also showed the fungus capable of causing leaf spots on the following herbecrops weeds commonly present in the corn fields: Cenchrus echinGtus, Chenopodium album, Chrysopogon aciculatus, Cynodon dactylon, Cyperus rotundus, Digitaria sanguinalis,Digitaria violascans, Echinochloa colona, Eleusine indica, Panicum maximum, Panicurn repens and Paspalum distichum. The pathogen also infects leaves of Saccharum officinarum, Sorghum bicolor and Triticum aestivum.
Subjects
玉米
葉斑病
雜草
corn (zea mays)
Exserohilum leaf spot
Exserohilum rostratum
host ranges
weeds
Publisher
中華民國植物病理學會
Type
journal article