Lecture 5 - Diseases of Brinjal and Bhindi PDF

Module 5: Diseases of Brinjal and Bhindi and it’s Management Summary Brinjal also known as an eggplant is widely grown in Asia, parts of Europe and Africa. It is one of the traditional vegetables grown in India and its crop productions are affected by many diseases like fungal, bacterial, and viral...

Module 5: Diseases of Brinjal and Bhindi and it’s Management Summary Brinjal also known as an eggplant is widely grown in Asia, parts of Europe and Africa. It is one of the traditional vegetables grown in India and its crop productions are affected by many diseases like fungal, bacterial, and viral with significant economic yield loss and reduce market value of the crop. Some of the important fungal diseases are Cercospora leaf spot caused by Cercospora melongenae which has a symptom of chlorotic lesions, angular to irregular in shape, later turning greyish brown with profuse sporulation at the center of the spot., Alternaria leaf spot is caused by Alternaria solani symptom with concentric rings, irregular, 4-8 mm in diameter and may coalesce to cover large areas of the leaf blade. Foot rot is caused by Fusarium incarnatum and has a character where conidia are scattered on aerial mycelium. Sclerotinia wilt is caused by Sclerotinia sclerotiorum which express the symptom circular to elongate water-soaked lesions closer to the inflorescence appear on the branches followed by watery soft rot. Bacterial wilt is caused by Ralstonia.Symptoms include wilting, stunting and yellowing of the foliage Okra also known as bhindi is an economically important vegetable crops grown in tropical and sub-tropical regions of the world. It is susceptible to many diseases where it is grown intensively. The Fusarium wilt disease is caused by Fusarium oxysporum. Its symptom includes yellowing and stunting of the plants later it caused wilting and rolling of the leaves and ultimately the plant dies. Cercospora leaf spot is caused by Cercosporamalayensis or, Cercosporaabelmoschi. The pathogen express indefinite leaf spots symptom but grows as a sooty mould on the lower surface of the leaves. The genus Cercospora has a distinct feature for identification i.e conidiophores geniculation. The viral disease Yellow vein mosaic (YVM) is caused by Begomo virus and size of virus and virus particles are spherical and isometric. OBJECTIVES The main objectives of this chapter are to acquaint the students about: i) the different diseases of brinjal and bhindi; ii) the scientific classification ; iii) the pathogen character of the different diseases of brinjal and bhindi. Introduction Brinjal is one of the most commonly grown vegetable crops of the country. India produces about 7.676 M mt of brinjal from an area of 0.472 M ha with an average productivity of 16.3 mt/ha. Its production is greatly reduced by many diseases like Cercospora leaf spot, Alternaria leaf spot, bacterial wilt and little leaf of brinjal. Fungal Diseases 1.Cercospora Leaf spot: This disease is characterized by its chlorotic lesions, angular to irregular in shape, later turning greyish brown with profuse sporulation at the center of the spot. Scientific classification Kingdom: Fungi Phylum: Ascomycota 1 Class: Dothideomycetes Subclass: Dothideomycetidae Order: Capnodiales Family: Mycosphaerellaceae Genus: Cercospora Species: melongenae Pathogen character Conidiophores borne singly or in fascicles, arising from stroma or directly from the vegetative hyphae, pale brown, septate or non-septate which are hyline to dark brown pigmented, continuous, simple or branched, uniform to elevate, sometimes obclavate, curved, smooth, conidia borne terminally and singly becoming lateral by sympodial development of the conidiophore, acicular to obclavate or cylindrical, rarely clavate, thin walled, multi septate. The conidiophore has a sub-apical growth, reason for the mature conidium to push aside, which lead to geniculations bearing scars at the area where conidia are detached. Conidiophore with distinct geniculation(knee like bends) is an important character for identification. Due to geniculation conidia are formed singly acrogenously i.e., at the tip. Conidia 4 - 10 celled, multi septate, hyaline or brown conidia, conidia measuring 63 - 140u x 14 - 17.5u. 2. Alternaria leaf Spot: This disease can be visualized only when spots with distinct concentric rings bands of light and dark colours, irregular, 4-8 mm in diameter and may coalesce to cover large areas of the leaf blade. Fruits causing large deep-seated spots and drop-off prematurely. Scientific classification Kingdom: Fungi Phylum: Deuteromycetes Class: Dothideomycetes Sub-class: Pleosporomycetidae Order: Pleosporales Family: Pleosporaceae Genus: Alternaria Species: solani Pathogen character Mycelium is septate, branched, light brown to dark brown. Conidiophores emerge through stomata and dark coloured. Conidia are single celled, muriform conidia with non-catenatae which means solitary conidia with long filiform beak. The conidium is 5-10 transverse septa and a few longitudinal or oblique septa. 3. Root Rot: The disease can be characterized when underground portion (i.e.root portion) causing rot. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Sordariomycetes Subclass: Hypocreomycetidae Order: Hypocreales 2 Family: Nectriaceae Genus: Fusarium Species: incarnatum Pathogen character Fusarium has a hyaline septate hyphae, short conidiophores, septatation with a terminal phialide, may be simple or branched. Conidia are formed at effuse sporodochia called pionnotes. Conidia are of two types micro-conidia which is single celled, oval or comma shaped, pyriform or elongate) and macro-conidia which has hyline, spindle shape with pointed ends, it also may have 3 or more septation, distinct pedicellate base. Macroconidia has a distinct feature of having foot cell. Macroconidia is straight, seldom curved, 3 septate24x 3.5 u, 7 septate 35 - 52.5 u x 3.5 - 5.2 u. Micro -conidia oval shaped, one or two celled , thin walled; 0 - septate 4 – 16u x 2 - 4u; 1 - sept ate 8 - 20 u x 2 - 4.5 u. Chlamydospores are formed from the hyphae or at macroconidia. Bacterial Diseases 4. Bacterial wilt: Bacterial diseases mostly show wilting, stunting, yellowing of the foliage and finally collapse of the entire plant are the characteristic symptoms of the diseases. The vascular system becomes brown. Bacterial ooze comes out from the affected parts. Systematic Classification Domain: Bacteria Phylum: Proteobacteria Class: Gamma proteobacteria Order: Pseudomonadales Family: Pseudomonadaceae Genus: Pseudomonas Pathogen character The bacterium is non-acid fast, non-spore forming, non-capsulated and motile by a polar flagellum. The bacterium produces acid but no gas in dextrose, sucrose, lactose and glycerol. Starch hydrolyzed with slight liquefaction of gelatin. 5.Sclerotinia wilt The disease is more important in tarai area (foot hills of H.P and Uttrakhand) of the country where it causes considerable yield losses. The genus Sclerotinia has a destructive characters to many vegetables. Pathogen show circular to elongate water-soaked lesions closer to the inflorescence appear on the branches followed by watery soft rot. Scientific classification Kingdom: Fungi Division: Ascomycota Class: Leotiomycetes Order: Helotiales Family: Sclerotiniaceae Genus: Sclerotinia Species: S. sclerotiorum Pathogen Character 3   The disease is caused by Sclerotinian sclerotiorum.  Mycelium in cultured innvitro and innvivo on host surface are hyaline, cottony, branched, consisting of closely septate hyphae and filled with dense granular protoplasm.  Fungus germinate by two means i.e. myceliogenic and carpogenic (forming apothecia). Primary infection occurs through ascospore whereas secondary infection takes place through mycelium.  Microconidia (spermatia) are produced on short lateral branches of the vegetative mycelium in chains.  When food supply is exhausted and the vegetative growth ceases, the hyphae with granular protoplasm collect in small dense masses and form sclerotia.  Sclerotia are white in colour later turn black.  The sclerotia also germinate by producing stalked apothecia, which range from one to five per sclerotium when proper humidity and light conditions are provided to overwintered sclerotia.  The best apothecial development takes place at 7-11°C and their production ceases at 16-28°C with low soil moisture.  Apothecia are brown in colour and are round or lobate type.  Asci are cylindrical measuring 108-153 x 4.5- 10 µm in size and each ascus contains eight ascospores, which are released in clouds.  Fungus produces oxalic acid which kills cells in advance resulting characteristic hollow stem. 5. Little leaf of Brinjal: Peculiar character is infected plant show a bushy appearance. Mostly, there is no flowering but if flowers are formed they remain green. Fruiting is rare. Scientific classification Kingdom: Bacteria Phylum: Tenericutes Class: Mollicutes Order: Mycoplasmatales Family: Mycoplasmataceae Genus: Mycoplasma Pathogen character Little leaf was first considered a disease caused by a virus. In 1969 it was attributed to a mycoplasma-like organism, closely related to aster-yellows and curly top. This organism having ovoid or spherical body.These measure 40-300 nm in dia. and lack a rigid cell wall. The Phytoplasma are present in phloem sieve tubes. It is a sap transmissible disease. The organism has been transmitted to Datura, tomato and tobacco. It occurs in nature on Daturafastuosa and Vincarosea. Natural transmission is through a vector, Cestiusphycytis (Eutettixphycytis) while Empoascadevastans is a less effective vector. Perennation of the organism is through its weed hosts. Diseases of Bhindi Okra popularly known as bhindi or lady finger is one of the important vegetables grown throughout the country. It is noted for its rich iron content and nutritive value. For the commercial, cultivation of okra has received a great set back under Indian conditions due to attack of different diseases (fungal, bacterial and viral) like powdery mildew, wilt, leaf spot 4 etc. Fungal Diseases 1. Fusarium wilt: This disease appears as yellowing and stunting of the plants followed by wilting and rolling of the leaves and finally the plant dies. Scientific classification Kingdom: Fungi Division: Ascomycota Class: Sordariomycetes Order: Hypocreales Family: Nectriacea Genus: Fusarium Species: F. oxysporum Pathogen character The disease is caused by Fusarium oxysporum f.sp. vasinfectum. The mycelium is hyaline and intracellular in the host. Macroconidia are mostly 3 septate and microconidia are 0 to 1 septate. Macroconidia are fusiform, falcate, curved and formed on sporodochia and pionnotes. In mass, these conidia appear buff to salmon orange in colour. The microconidia are 5-12 x 2-3.5 µm while macroconidia are 40-50 x 3-4.5 µm in size. Both intercalary and terminal chlamydospores are formed which are broadly ovate. 2. Cercospora leaf spot: This pathogen produces indefinite leaf spots but grows as a sooty mould on the lower surface of the leaves. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Dothideomycetes Order: Capnodiales Family: Mycosphaerellaceae Genus: Cercospora Pathogen character The disease is caused by three species of Cercospora like C. abelmoschi ,C. hibiscina andC. malayensis. These species differ in their size of conidiophores and conidia. In C. abelmoschi, the conidiophores are long, brown and bear pale olivaceous, slightly tapered conidia. The conidiophores of C. hibiscina are extremely long sometimes up to 1000 µm in size, narrow and bear conidia that are sometimes hyaline and appreciably more narrow then those of C. abelmoschi. The conidiophores of C. malayensis are borne in clusters of 5-20 and bear conidia, which are colourless, narrow, long, and tapering from the blunt base to the sharp tip. 3. Powdery mildew Powdery mildew is an important disease of this crop and under favourable weather condition causes significant yield reductions particularly if the infection takes place at in early stages of plant growth, produces minute discoloured patches with thin fine meshwork of white mycelium arising at many places on the surface of lower leaves. The conidia after landed on the host surface, the germination throughout germ tubes, elongate and form an appressorium 5 at the tip in the initial stage of infection, than the penetration hyphae arise to penetrate the epidermal wall which enters the cell than the bulbous base, finger like projections called haustoria arise. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Leotiomycetes Subclass: Leotiomycetidae Order: Erysiphales Family: Erysiphaceae Genus: Erysiphe Species: cichoracearum Pathogen character The disease is caused by an obligate parasite Erysiphecichoracearum. The conidia are single celled, hyaline, barrel-shaped and in long chains. The conidial dimensions vary with the physiologic race and the host. Cleistothecia are globose, dark with hyaline to dark brown and mycelioid appendages. They contain 8 to 18 asci and the asci are pedicellate, ovate to broadly ovate or ellipsoid. The number of ascospores per ascus is usually two, rarely three. The ascospores are one celled and hyaline oval to sub-cylindrical. 4. Yellow vein mosaic (YVM): The characteristic symptoms include vein yellowing and thickening of leaves forming a net-work of veins and vein lets in the infected leaves. Virus classification Group: Group II (ssDNA) Family: Geminiviridae Genus: Begomovirus Pathogen character The disease is caused by Yellow Vein Mosaic Virus (YVMV) and belongs to the Bigeminivirus. The size of virus is 18 x 30 nm.Virus particles are spherical, isometric measuring 28-30 nm. Conclusion Brinjal and Bhindi is attacked by several diseases such as fungal, bacteria and viruses. Its production is hampered by several factors like biotic and abiotic factors. The management of the diseases can be obtained only if we understand the character of the pathogen and as well as the symptoms involved. TRANSCRIPT Diseases of Brinjal Brinjal is one of the most commonly grown vegetable crops of the country. India produces about 7.676 M mt of brinjal from an area of 0.472 M ha with an average productivity of 16.3 mt/ha. Its production is greatly reduced by many diseases like Cercospora leaf spot, Alternaria leaf spot, bacterial wilt, little leaf of brinjal Fungal Diseases 6 1.Cercospora Leaf spot: This disease can be characterized by itschlorotic lesions, angular to irregular in shape, later turning greyish brown with profuse sporulation at the center of the spot. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Dothideomycetes Subclass: Dothideomycetidae Order: Capnodiales Family: Mycosphaerellaceae Genus: Cercospora Species: melongenae Pathogen character Conidiophores borne singly or in fascicles, arising from stroma or directly from the vegetative hyphae, pale brown, septate or non septate which are hyline to dark brown pigmented, continuous, simple or branched, uniform to elevate, sometimes obclavate, curved, smooth, conidia borne terminally and singly becoming lateral by sympodial development of the conidiophore, acicular to obclavate or cylindrical, rarely clavate, thin walled, multi septate. The conidiophore has a sub-apical growth, reason for the mature conidium to push aside, which lead to geniculations bearing scars at the area where conidia are detached. Conidiophore with distinct geniculation(knee like bends) which is an important character for identification. Due to geniculation conidia are formed singly acrogenously i.e., at the tip. Conidia 4 - 10 celled,multi septate, hyaline or brown conidia,conidia measuring 63 - 140u x 14 - 17.5u. 2. Alternaria leaf Spot: This disease can be visualized only when spots with distinct concentric ring bands of light and dark colours, irregular, 4-8 mm in diameter and may coalesce to cover large areas of the leaf blade. Fruits causing large deep-seated spots and drop-off prematurely. Scientific classification Kingdom: Fungi Phylum: Deuteromycetes Class: Dothideomycetes Subclass: Pleosporomycetidae Order: Pleosporales Family: Pleosporaceae Genus: Alternaria Species: solani Pathogen character Mycelium is septate, branched, light brown to dark brown. It has inter and intra cellular. Conidiophores emerge through stromata and dark colored. Conidia are single- celled, muriform conidia with non-catenatae which means solitary conidia with long filiform beak. The conidium is 5-10 transverse septa and a few longitudinal or oblique septa. 3. Root Rot: The disease can be characterized when underground portion (i.e. root portion) 7 causing rot. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Sordariomycetes Subclass: Hypocreomycetidae Order: Hypocreales Family: Nectriaceae Genus: Fusarium Species: incarnatum Pathogen character Fusarium has a hyaline septate hyphae, short conidiophores, septatation with a terminal phialide, may be simple or branched. Conidia are formed at effuse sporodochia, called pinnotes. Conidia are of two types microconidia which is single celled, oval or comma shaped, pyriform or elongate) and macroconidia which has hyline, spindle shape with pointed ends, it also may have 3 or more septation, distinct pedicellate base. Macroconidia has a distinct feature of having foot cell. Macroconidia straight, seldom curved, 3 septate 24x 3.5 u, 7 septate 35 - 52.5 u x 3.5 - 5.2 u. Micro -conidia oval shaped, one or two celled , thin- walled; 0 - septate 4 – 16u x 2 - 4u; 1 - septate 8 - 20 u x 2 - 4.5 u. Chlamydospores are formed from the hyphae or at macroconidia. Bacterial Diseases 4. Bacterial wilt: Bacterial diseases mostly show wilting, stunting, yellowing of the foliage and finally collapse of the entire plant are the characteristic symptoms of the diseases. The vascular system becomes brown. Bacterial ooze comes out from the affected parts. Systematic Classification Domain: Bacteria Phylum: Proteobacteria Class: Gamma proteobacteria Order: Pseudomonadales Family: Pseudomonadaceae Genus: Pseudomonas Pathogen character The bacterium is non-acid fast, non-spore forming, non-capsulated and motile by a polar flagellum. The bacterium produces acid but no gas in dextrose, sucrose, lactose and glycerol. Starch hydrolyzed with slight liquefaction of gelatin. 5.Sclerotinia wilt The disease is more important in tarai area (foot hills of H.P and Uttrakhand) of the country where it causes considerable yield losses.The genus Sclerotinia has a destructive characters to many vegetables. Pathogen show circular to elongate water-soaked lesions closer to the inflorescence appear on the branches followed by watery soft rot. Scientific classification Kingdom: Fungi 8 Division: Ascomycota Class: Leotiomycetes Order: Helotiales Family: Sclerotiniaceae Genus: Sclerotinia Species: sclerotiorum Pathogen Character  The disease is caused by Sclerotinian sclerotiorum.  Mycelium in cultured innvitro and innvivo on host surface are hyaline, cottony, branched, consisting of closely septate hyhae, and filled with dense granular protoplasm.  Fungus germinate by two means i.e. myceliogenic and carpogenic (forming apothecia). Primary infection occurs through ascospore whereas secondary infection takes place through mycelium.  Microconidia (spermatia) are produced on short lateral branches of the vegetative mycelium in chains.  When food supply is exhausted and the vegetative growth ceases, the hyphae with granular protoplasm collect in small dense masses and form sclerotia.  Sclerotia are white in colour later turn black.  The sclerotia also germinate by producing stalked apothecia, which range from one to five per sclerotium when proper humidity and light conditions are provided to overwintered sclerotia.  The best apothecial development takes place at 7-11°C and their production ceases at 16-28°C with low soil moisture.  Apothecia are brown in colour and are round or lobate type.  Asci are cylindrical measuring 108-153 x 4.5- 10 µm in size and each ascus contains eight ascospores, which are released in clouds.  Fungus produces oxalic acid which kills cells in advance resulting characteristic hollow stem. 5.Little leaf of Brinjal: Peculiar character is infected plant show a bushy appearance. Mostly, there is no flowering but if flowers are formed they remain green. Fruiting is rare. Scientific classification Kingdom: Bacteria Phylum: Tenericutes Class: Mollicutes Order: Mycoplasmatales Family: Mycoplasmataceae Genus: Mycoplasma Pathogen character Little leaf was first considered a disease caused by a virus. In 1969 it was attributed to a mycoplasma-like organism, closely related to aster-yellows and curly top. This organism having ovoid or spherical body and measure 40-300 nm in dia. and lack a rigid cell wall. The phytoplasma are present in phloem sieve tubes. It is a sap transmissible disease. The organism has been transmitted to Datura, tomato and tobacco Diseases of Bhindi 9 Okra popularly known as bhindi or lady finger is one of the important vegetables grown throughout the country. It is noted for its rich iron content and nutritive value. For the commercial cultivation of okra has received a great set back under Indian conditions due to attack of different diseases (fungal, bacteria and virus) like powdery mildew, wilt, leaf spot and YVMV. Fungal Diseases 2. Fusarium wilt: This disease appears as yellowing and stunting of the plants followed by a wilting and rolling of the leaves and finally the plant dies. Scientific classification Kingdom: Fungi Division: Ascomycota Class: Sordariomycetes Order: Hypocreales Family: Nectriacea Genus: Fusarium Species: oxysporum Pathogen character  The disease is caused by Fusariumoxysporum f.sp. vasinfectum.  The mycelium is hyaline and intracellular in the host.  Macroconidia are mostly 3 septate and microconidia are 0 to 1 septate.  The microconidia are 5-12 x 2-3.5 µm while macroconidia are 40-50 x 3-4.5 µm in size.  Macroconidia are fusiform, falcate, curved and formed on sporodochia and pionnotes. In mass these conidia appear buff to salmon orange in colour.  Both intercalary and terminal chlamydospores are formed which are broadly ovate. 2. Cercospora leaf spot: This pathogen produces indefinite leaf spots but grows as a sooty mould on the lower surface of the leaves. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Dothideomycetes Order: Capnodiales Family: Mycosphaerellaceae Genus: Cercospora Pathogen character  The disease is caused by three species of Cercospora like C. abelmoschi , C. hibiscina andC. malayensis.  These species differ in their size of conidiophores and conidia.  In C. abelmoschi, the conidiophores are long, brown and bear pale olivaceous, slightly tapered conidia.  The conidiophores of C. hibiscina are extremely long sometimes upto 1000 µm in size, narrow and bear conidia that are sometimes hyaline and appreciably more 10  narrow then those of C. abelmoschi.  The conidiophores of C. malayensis are borne in clusters of 5-20 and bear conidia, which are colourless, narrow, long, and tapering from the blunt base to the sharp tip. 3. Powdery mildew Powdery mildew is an important disease of this crop and under favourable weather condition causes significant yield reductions particularly if the infection takes place in early stages of plant growth, produces minute discoloured patches with thin fine meshwork of white mycelium arising at many places on the surface of the lower leaves. The conidia after landed on the host surface, germination throughout germ tubes, elongate and form an appressorium at the tip in the initial stage of infection, than the penetration hyphae arise to penetrate the epidermal wall which enters the cell than the bulbous base, finger like projections called haustoria arise. Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Leotiomycetes Sub-class: Leotiomycetidae Order: Erysiphales Family: Erysiphaceae Genus: Erysiphe Species: cichoracearum Pathogen character  The disease is caused by an obligate parasite Erysiphe cichoracearum.  The conidia are single celled, hyaline, barrel-shaped and in long chains.  The conidial dimensions vary with the physiologic race and the host.  Cleistothecia are globose, dark with hyaline to dark brown and mycelioid appendages.  They contain 8 to 18 asci and the asci are pedicellate, ovate to broadly ovate or ellipsoid.  The number of ascospores per ascus is usually two, rarely three. The ascospores are one celled and hyaline oval to sub-cylindrical. 4. Yellow vein mosaic (YVM): The characteristic symptoms include vein yellowing and thickening of leaves forming a net-work of veins and vein lets in the infected leaves. Virus classification Group: Group II (ssDNA) Family: Gemini viridae Genus: Begomovirus Pathogen character The disease is caused by Yellow Vein Mosaic Virus (YVMV) and belongs to the Bigemini virus.The size of virus is 18 x 30 nm. Virus particles are spherical, isometric measuring 28- 30 nm. Conclusion Brinjal and bhindi is attacked by several diseases such as fungal, bacteria and viruses.Its production is hampered by several factors like biotic and abiotic factors. The management of the diseases can be obtained only if we understand the character of the pathogen and as well 11 as the symptoms involved. FREQUENTLY ASKED QUESTIONS (FAQS) Q1. Name one bacterial diseases of brinjal and also write its systematic classification. Ans: Bacterial wilt: Bacterial diseases mostly show wilting, stunting, yellowing of the foliage and finally collapse of the entire plant are the characteristic symptoms of the diseases. The vascular system becomes brown. Bacterial ooze comes out from the affected parts. Systematic Classification Domain: Bacteria Phylum: Proteobacteria Class: Gamma proteobacteria Order: Pseudomonadales Family: Pseudomonadaceae Genus: Ralstonia Q2. Write the pathogenic character of Cercospora leaf spot of bhindi. Ans: These species differ in their size of conidiophores and conidia. In C. abelmoschi, the conidiophores are long, brown and bear pale olivaceous and has slightly tapered conidia. The conidiophores of C. hibiscina are extremely long sometimes up to 1000 µm in size, narrow.The conidiophores of C. malayensis are borne in clusters of 5-20 and bear conidia, which are colourless, narrow, long and tapering from the blunt base to the sharp tip. Q3. Write the scientific classification of root rot of brinjal. Ans: Scientific classification Kingdom: Fungi Phylum: Ascomycota Class: Sordariomycetes Subclass: Hypocreomycetidae Order: Hypocreales Family: Nectriaceae Genus: Fusarium Species: incarnatum Q4. Write the pathogen character of root rot of brinjal. Ans: Fussarium has a hyline septate hyphae, short conidiophores, septatation with a terminal phialide, may be simple or branched. Conidia are formed at effuse of sporodochia, called pionnotes. Conidia are of two types, microconidia which is single celled, oval or comma shaped, pyriform or elongate) and macroconidia which has hyline, spindle shape with pointed ends, it also may have 3 or more septation, distinct pedicellate base. Macroconidia has a distinct feature of having foot cell. Macroconidia are straight, seldom curved, 3 septate24x 3.5 u, 7 septate 35 - 52.5 u x 3.5 - 5.2 u. Microconidia are oval shaped, one or two celled , thin walled; 0 - septate 4 – 16u x 2 - 4u; 1 - septate 8 - 20 u x 2 - 4.5 u. Chlamydospores are formed from the hyphae or at macroconidia. Q5. Mention one important viral disease of bhindi and its classification. Ans: Yellow vein mosaic (YVM): The characteristic symptoms include vein yellowing and 12 thickening of leaves forming a network of veins and veinlets in the infected leaves. Virus classification Group: Group II (ssDNA) Family: Gemini viridae Genus: Begomovirus GLOSSARY 1. Mycelium (pl. Mycelia): The mass of thin, microscopic, hair-like structures that forms the vegetative part of a fungus. 2. Little leaf: In diseased plants, the leaves are malformed into tiny chlorotic structures. 3. Sporulation: The process of producing spores. 4. Rot: The softening, discoloration, and often disintegration of a succulent plant tissue as a result of fungal or bacterial infection. 5. Sclerotia: A hard resting body, resistant to adverse environmental conditions and may remain dormant for long period of time and germinates when favorable condition return. 6. Obligate parasite: An organism that can live and obtain food only from living protoplasm of the host. It cannot be grown in artificial culture media. 7. Appressorium: A swollen, flattened, pressing organ arising from the tip of a hypha or germtube that facilitates the attachment to the host. 13