Spots are dark brown in color and form concentric rings, or a. If severe symptoms are found then contact NPPC for advice. Early blight infections appear as spots that may start out circular or irregular in shape. The use of fungicide is not recommended as it is not economically justified in Bhutan.Avoid overhead irrigation as this can splash the disease from plant to plant.For seed potatoes the recommendation is 60 cm and 15 cm. Late blight, caused by the oomycete Phytophthora infestans, continues to be the main biotic constraint of potato production.Annual losses have been estimated to be about 6. For table potatoes rows should be 70 cm apart and plants within a row 20 cm apart. This chapter discusses the major potato diseases worldwide: late blight, early blight, wart, and powdery scab. Plant seed potatoes at recommended spacings.Remove plant debris after harvest as it harbours the disease.Use polythene bags to transport them out of the field, as you otherwise spread the disease. Remove all affected leaves, and destroy them (burning or deep burial).Resistance is not specifically bred for, but considerable differences in susceptibility has been seen among varieties in other countries. Consider taking management action when 2-3 leaves are affected per 20 plants. Look for lesions on the lower, shaded stems. Hosts: It is mainly a pest of potato, but has also been reported on tomato and chilli in Bhutan. It rarely causes economic problems in Bhutan. Early blight develops more slowly than late blight so generally gets dominated when they co-occur. When can damage be expected? Generally damage requires higher temperatures and less humidity compared to late blight. Spores are readily moved between plants and fields by wind and water. Lifecycle: Early blight overwinters in plant debris, soil and infected potato tubers.ĭispersal: Initial infection can be through infected seed potatoes. Early blight lesion Tubers infected with early blightĬonfusion with other pests: Late blight also cause lesions, but early blight lesions are very characteristic owing to their defined margins and concentric rings. Tuber lesions are dry, dark and pressed into the tuber surface, with the underlying flesh turning dry and brown. Necrotic (dead) spots are most common on the lower shaded leaves and stems. It causes circular, dark brown lesions with concentric, target-like rings. The spots are surrounded by concentric rings of leathery tissue. Tomato Early Blight is a fungal disease of Solanaceous crops caused by Alternaria solani. SYMPTOMSīrown, angular necrotic spots develop on leaves. It can cause severe defoliation of seed potato production in greenhouses. Although ubiquitous it rarely causes widespread defoliation in the open air. The findings of the present study indicated that early blight of tomato incidence and severity varies among districts, date of planting, crop density, weed management, and environmental factors. Where and when is it a problem? Early blight co-occurs with late blight, but it is more prevalent in warmer conditions, so also extends down to lower altitude areas such as Tsirang and Sarpang. Early blight of tomato is the most economically important disease was found widely distributed in all the surveyed areas. However, treatment is not often required. Why is it a problem? Early blight is a fungus that, looks like late blight, can defoliate and even destroy unprotected potato crops.
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