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Fungal disease which occurs mainly in the cool regions. It is occurring mainly from summer to autumn on leaves. Lesions are at first like small points, but later become to reddish brown, small ones with faint brown halos. They may become yellowish brown lesions according to the sorghum variety. These lesions fuse later and leaf blight is induced. It is known to spread by the dispersion of the conidia on the lesions and by the seed transmission. |
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Typical, spot-causing fungal disease in the cool region. The spindle shaped lesion of border part purple brown, the center part ash white, 2-10cm in length, and about 0.5-1cm in the width is formed by being generated before and behind the flowering stage. For the lesion to fuse back and the entire leaf is withering from the gray to purple. The center part is formed the spore and disperses blacking it the mold and this and spreads when the lesion becomes old. It occurs severely comparatively under the low temperature condition and the influence on amount grows when especially spreading before the stage of flowering. |
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Minor fungal disease occurring at present only in Tochigi Pref. It begins to occur from the end of summer. The lesion is dark red to purple, round to oval, 1-3 cm in length, 0.5-1cm in width, and becomes irregular shape. Especially, many form small black grain (pycnidia) which projects hard on the lesion on the back of the leaf and there is a touch feeling like a sand paper. There are a lot of spores in the pycnidia and they gush when maturing and disperse by wind and rain. |
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The only rust disease of sorghum that occurs at the latter stage. The disease produces small, purple to reddish brown uredinia of 1-3 mm in length and 0.5-2 mm in width. Uredinia are formed in the way of piercing through the leaf and the entire leaf seems to be burnt when occurring severely. A little long and slender telia are produced in autumn and the teleutospore is formed in it. The disease occurs severely under the low temperature and high humidity condition and considerably influences the yield of the grain. Some kinds of creeping sorrels are considered to be alternate hosts, but this has not yet been confirmed in our country. |
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An important fungal disease which leads to withering of the entire plant body if occurring severely. The disease firstly occurs in the ground side of stem around the rainy season and progresses up through sheaths. The lesion becomes cloud-shaped, ash brown to ash white with reddish brown border. Brown sclerotia with a smooth surface are produced on the lesion at the latter stage of the occurrence. They drop to ground, and become the primary inocula of next year. It occurs severely under high temperature (especially 30C or more) and high humidity condition and transmits by the infected leaves contacting to healthy ones. Because most of the pathogen are R.solani AG-1 IA, the same AG-group with rice, it often occurs severely when sorghum is cultivated in paddy rice fields. |
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Fungal disease occurring in heads. Whole heads are infected and dicolor to blackish brown. Details about the occurrence are unknown in Japan. |
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The disease has not yet reported in Japan, but the damage is largest and the most important disease in the world. The whole plant is infected at the seedling stage and it shrinks severely and turns to yellow from the lower leaves. It is characteristic that white stripes are formed along the leaf vein and the leaves tear from the part of stripes. White molds are produced in the abaxial surface of the infected leaves in the cool and wet conditions. These are masses of conidia (zoosporangia), and they disperse and spread by wind and rain. |
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Representative spot-causing fungal disease in the warm regions. The disease produces red purple and oval lesions of 0.5-2cm in length and 0.3-1cm in width abundantly on leaves from the end of summer to autumn. The lesions are produced by the accumulation of antocyan responding to the infection of the pathogen. When the lesions become old, the center part discolors to yellowish brown and the whole leaf withers before long. The lesions may become yellowish brown according to the sorghum varieties. The causal organism can infect sudangrass and johnsongrass strongly. |
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Fungal disease whose occurrence is increasing especially in the warm regions recently. The disease produce small, red to purple spots in the lower leaves at the rainy season and these lesions expand gradually. When they expand to some extent, they becomes red to purple and zonate spots of 0.5-5cm in length and 0.2-5cm in width. Pink mass of conidia is formed on the surface of the lesion in the high humidity condition, and this disperses by wind and rain, etc. When the lesion becomes old, black microsclerotia are formed in the infected tissues, overwinter, and becomes the inoculum source of next year. |
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