- 期刊
環境因子對檬果炭疽病發生之影響
Effects of environmental factors on disease incidence of mango anthracnose
摘要
檬果炭疽病菌(Collectotrichum gloeosporioides)之分生胞子可以無傷痍侵染愛文檬果的幼嫩組織(新葉、幼莖、和花穗)與整個發育期的果實，且只要濕度飽和，受感染部位均可立即顯現病徵。當濕度飽和時，生長發育期與硬核期(綠熟果)之愛文檬果果實在被感染後，表皮上會出現紫紅色小斑點。而幼葉亦可被感染後不立即出現病徵，而至組織老熟後才出現黑色、稍凹陷的多角形病斑，引起落葉。以上兩種檬果炭疽病病徵在前人報告中均尙未被描述過。留在樹上之新生與老舊病斑，枯枝以及地面的枯枝與落葉(可被病菌腐生)，在濕度飽和時，均會形成大量的分生胞子，可爲病害感染源所在。除水分(雨水與露水)外，褐葉蟬亦可以攜帶檬果炭疽病菌，但空氣與風不能傳播本病害。自1980年至1984年於台南玉井檬果專業區與嘉義農試所檬果果園設置試驗田，輔以套袋方法，探討溫度、濕度、降雨、及露水等因子對愛文檬果炭疽病發生之影響。結果顯示，多雨、高濕、及高溫均有助於病害發生，降雨較多時，接受自然感染之果實在後熟後出現之病斑數亦較多，兩者之直線相關係數(r)均在0.76以上；濕度、溫度、及露水雖亦與炭疽病之罹病度正相關，但不如降雨重要。濕度較高或降雨較多時，新生葉片上出現之紅褐色病斑數或當葉片老熟後出現之黑色病斑數亦較多。
並列摘要
Conidia of Collectotrichum gloeosporioides were able to attack the fruit in all growing stage, young leaves, stems and flowers of ＂Irwin＂ mango without wounding. Moreover, all infected sites developed disease symptoms without going through latent period if the surface was under saturated moisture conditions. Under such conditions, the infected fruit in growing stage and green mature stage showed numerous tiny reddish-purple spots on the affected skins within 3-5 day. Sometimes, leaves infected in the expanding stage did not show disease symptoms until they were mature and aged. The disease spots on the aged leaves were black, irregular, and with a diameter of 2-3 mm. Most aged leaves fell after the appearance of numerous spots. These two types of anthracnose symptoms commonly appearing on ＂Irwin＂ have not been described before. The anthracnose pathogen was disseminated by water (including rain and dew), but not air or wind in the fields. C gloeosporioides was isolated from the bodies some insects caught from mango fields during blossom period. Conidia of the fungus also appeared on the dead branches as well as the fallen leaves and twigs which were enveloped in the plastic bags under moist conditions. From 1980 through 1984 the relationships between the climatic factors and mango anthracnose were studied in two ＂Irwin＂ mango fields at Yu jing and Chiayi Results showed that rainfall, high relative humidity (RH), and higher temperature favoured the disease development. Continuous rainfall was the most important factor contributing to the serious incidence of anthracnose on mango fruit in Taiwan. The linear relationship of amount of rainfall in the week correlated highly (r＞0.76) and significantly (P＜0.01) with numbers of black spots appeared on the ripened fruit which was enveloped with paper bag in growth stage, but exposed one week for nature infection. There was a positive correlation between RH or rainfall during the leaf expanding stage and the numbers of reddish-brown spots on the young leaves and black appeared on the same leaves after mature.