symptoms of disease in plants

symptoms of disease in plants

• 1.
  T.C.B College ofAgriculture And Research Station.BILASPUR chattisgarh Presented To; Presented By; Dr. R.K.S. Tiwari SHEKH ALISHA Dept. of Plant pathology B.Sc. Ag 2nd yr 2nd sem.. SYMPTOMS OF DISEASE SESSION -2015-16
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  • C. malayensiscauses brown, irregular spots and C. abelmoschi causes sooty black, • angular spots on lower surface of leaves • Both the leaf spots cause severe defoliation and are common during humid season CAUSAL ORGANISM: Cercospora abelmoschi • Symptoms mainly appear as on minute spots mainly on the lower surface of the leaves which later on increases in size and appear as rectangular in shape and is confined to intervenial area. • Affected leaves roll wilt and fall down. • Symptoms starts on petiole as olivaceous spot or lesions as a result the petiole detaches from twigs or branches and defoliation occurs.
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  CAUSAL ORGANISM: Leptosphaeriaconiothyrium • Spots start as small yellow or reddish discolouration around wound that turns with a dark brown border. • Drying of twigs starts with development of elongated lesions of brownish color followed by drying of affected tissue.
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  CAUSAL ORGANISM: Abiotic& Biotic causes 1.Bunchy top 2.Vegetative malformation 3.Floral malformation • Bunchy top: Excessive formation of leaves on the affected part of plant • Vegetative malformation: Excessive formation of scaly leaves on affected plants and directly attached to the branches arising from auxillary buds and nodes. • Floral malformation: Whole infloresence is converted into thick leafy stucture and becomes sterile in nature.
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  CAUSAL ORGANISM: Phytopthorainfestans (mont) de Bary • Initially starts from leaf tips or margins and spread inward • Small water soaked or faded green patches on upper surface of leaf which turn brown • Spots enlarge and zonations as concentric rings develop in them • Downy growth of the pathogen correspondingly on lower surface • Progressive defoliation and collapse of plants under favourable conditions • Water soaked stripes on stem which becomes necrotic • Purplish brown spots appear on skin of tubers • On cutting, the affected tubers show rusty brown necrosis from surface to the centre • Decay of plant parts under favourable weather which emits foul smell