IDDI KHAMISI MICRIOBOLOGY ASSIGNMENT.docx - PWANI UNIVERSITY NAME IDDI KHAMISI CHUMA REGNO E37S\/PU\/3155\/15 COURSE BACHELOR OF EDUCATION SCIENCE UNIT

IDDI KHAMISI MICRIOBOLOGY ASSIGNMENT.docx - PWANI...

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PWANI UNIVERSITY NAME : IDDI KHAMISI CHUMA REGNO : E37S/PU/3155/15 COURSE : BACHELOR OF EDUCATION SCIENCE UNIT CODE : SZL B 404 UNIT TITLE : APPLIED MICROBIOLOGY TASK : SYMPTOMS OF FUNGAL INFECTION IN PLANTS LECTURER : DR. MWAFAIDA
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INTRODUCTION A plant disease is any abnormal condition that alters the appearance or a function of a plant. This is caused n by infectious fungi, bacteria, viruses and nematodes or by non-infectious agency such as sun burns and mineral deficiency. Fungi infections accounts for 85% of plant diseases as they are widely spread and more destructive compared to any other disease of plants. Fungi cause significant low plant yields followed by reduction of crop quality and short life spans of plant due to death or changes in biological processes such as assimilation, respiration enzyme activities and impairment in growth and development. Individual species of fungi can parasitize one or many different kinds of plants. SYMPTOMS OF FUNGAL INFECTIONS IN PLANTS Symptom is defined as the changes brought about in the plant as a result of interaction of the plant, the pathogen and prevailing environmental conditions. Sign, compared with symptom, is the pathogen seen on the host plant. Symptoms caused by fungal pathogens mainly differ from the symptoms by rest of the pathogens. These symptoms can be broadly categorized as following depending upon the processes involved in the appearance of disease symptoms on the host. a. Necrotic symptom These symptoms involve the death and destruction of plant tissues resulting in brittle appearance of the tissue. All the symptoms in this category involve the necrosis of the tissue from the reaction with the pathogen and result in the formation of dead cells and tissues. The fungal pathogen in this case when reaches the host surface secrets enzymes which kill the tissue and then digest the nutrients from the dead tissues, conversely the tissue death may also occur as a result of the hypersensitive response (HR) which is the defense mechanism of host against the establishment and spread of the pathogen on host. In any case, the symptoms produced can be either localized (at the point of infection with host) or systemic (spreading though out the foliage, or stem, or entire plant). Following symptoms involve death and destruction of host tissue as a result of pathogen infection. i. Leaf Spots : These are the localized lesions produced on the leaves of the host plants as a result of pathogen infection. Such as Cercospora species and Alternaria species Cercospora leaf spot (with shot holes) on Plum leaf
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ii. Shot hole : The dead tissue on the leaves falls out leaving behind holes. This symptom is common
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