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- Epidemiology of Leaf Spot of Maize (Zea mays L.) Caused by Bipolaris...
Epidemiology of Leaf Spot of Maize (Zea mays L.) Caused by Bipolaris Maydis (Nisikado and T. Miyake) Shoem in East Kalimantan, Indonesia
Dissertation Abstract:
The epidemiology of leaf spot of maize caused by Bipolaris maydis Nisik. and Miy. was studied. Weather factors from all over Indonesia and regions in East Kalimantan were correlated to disease prevalence, development of which was significantly influenced by temperature, relative humidity, and rainfall.
The effect of host resitance was studied in Part II. Resistant cultivars had a longer incubation period, smaller lesion size, and lower disease severity. Disease development and infection rate were higher in susceptible cultivars--Pioneer 3012 was twice that of Composite 5, and thrice that of Hibrida CP I-2.
An experimental study of leaf spot development in Lempake and Purwajaya in East Kalimantan showed significant differences, with infection rate and average disease severity significantly higher in national compared with local cultivars.
The effects of aggressiveness on disease development were studied under laboratory and field conditions using isolates collected from around East Kalimantan. The Malinau isolate was the most aggressive while Tarakan was the least aggressive. There was high correlation between disease severity and yield loss. The area-under-the-disease-progess-curve method explained the relationship between disease and yield loss with the regression model Y + 8.885 + 0.675 X (R2 + 0.827).