diseases of yam

Tubers and feeder roots are galled. Learn more about your crops in our library, Learn about ways to keep your crops healthy, Small, dark brown spots or black lesions on leaves which may be surrounded by a chlorotic halo; leaf necrosis; dieback of stem; withered leaves and scorched appearance, Disease overwinters in plant debris; occurs worldwide. Stat. Flattened oval to round disc-like insect covered in waxy substance on tree branches; insects attract ants which may also be present; insect colony may also be associated with growth of sooty mold due to fungal colonization of sugary honeydew excreted by the insect, Insects have a wide host range; often tended by ants which farm them for their sugary honeydew secretions, Yam tuber infested by white scale insect (2). Yam Anthracnose Disease (YAD) can cause up to 80% yield loss where it is endemic. this site functions with internal linking marked in colours. its all about life The leaves and tubers are covered with small white scales from field to storage. Information provided by https://coleacp.org. A shoestring virus, which is transmitted mechanically and by aphids with particles consisting of flexuous rods 600 nm in length, is known to occur in various species of yam. Pests and diseases of yam and their control methods Pests of Yam Yam tuber pests makes holes on tubers, resulting in low tuber marketability. Greater and lesser yam beetles are both important pests of yams in West Africa. A shoestring virus, which is transmitted mechanically and by aphids, with particles consisting of flexuous rods 600 nm in length, is known to occur in various spp. Yam mosaic virus is always associated with yam mild mosaic virus, yam badnaviruses and cucumber mosaic virus in Africa making this disease more complex. You may use , Click here to go to the topics page to know more about the crop. For maximum yield, the yams require a humid tropical environment, with an annual rainfall over 1500 mm distributed uniformly throughout the growing season. Reduction in edible portion of tubers. It will be useful for people who smoke in their menu, as they lack vitamin A in their bodies, which can cause the development of various diseases. We reviewed a total of 73 insect species associated with Dioscorea species in different parts of the world. Yam is infested by 48 species when the crop is in the field, and after harvest (i.e. of Plant Pathology) Pegus, J.E. In that case scrap out the external layer of tuber to check the disease incidence. d) Aphids. The disease is recorded from Fiji, Papua New Guinea, New Caledonia, Niue, Samoa, Solomon Islands, Tonga, and Vanuatu. Today, you’ll also find topical wild yam creams that are meant to raise low progesterone levels, which can help ease PMS. ), which are evident by the disfigurement they cause to tubers (Figs. Yam anthracnose disease is caused by Colletotrichum gloesporioides Penz. Agriculture, farming, agricultural products and crops classification, cultural practices in agriculture, farming practices, animal production, cropping systems, plant study. Their growth and dormant phases correspond respectively to the wet season and the dry season. and Nicotiana benthamiana.In extracts of D. cayenensis leaves infectivity was lost after 10 min at 60 d̀C but not 55 d̀C and after dilution to 10 ‐3 but not 10 ‐2.A purification procedure is described. Anthracnose can be prevented using a fungicide with benomyl, but you need to remove affected plants and all plant debris from the field immediately in order to prevent the spread of the disease. Central Exp. The major disease affecting Dioscorea cayenensis in the Ivory Coast is caused by a virus which was transmitted by mechanical inoculation to some Dioscorea spp. stem basal canker (F. Protozoan diseases in animals pdfyam diseases and control pdf Cassava Diseases Prevention and Control to Ensure Food The virus is transmitted by aphids and tubers/setts. (teleomorph Glomerella cingulata [Stonem.] Disease is reported in West Africa , … The leaves turn yellow in color. People with diabetes are allowed to eat yam, as due to the low glycemic index after eating a root crop, the sugar level remains unchanged. Various virus, bacterial and fungal diseases of yam have been reported in Nigeria since 1956. Yam mosaic virus is always associated with yam mild mosaic virus, yam badnaviruses and cucumber mosaic virus in Africa making this disease more complex. Yam (Dioscorea spp.) Yam tubers infested by nematode and white scale insect. Of these, Yam mosaic virus (YMV, genus Potyvirus), Yam mild mosaic virus (YMMV, genus Potyvirus) and Dioscorea bacilliform viruses (DBVs, genus Badnavirus) are widespread in West Africa and YMV has been shown to cause important diseases in yam [3,8,9,10]. Yam mosaic virus, Yam mosaic virus and Yam mild mosaic potyvirus, Cucumovirus, Dioscorea bacilliform virus, Potexvirus Dioscorea latent virus. Due to the losses incurred through the effect of diseases such as YAD, yam breeders and other affiliated scientists are trying to breed for plant materials with resistance to this disease. ), MAIN PESTS AND DISEASES OF FRENCH BEANS (Phaseolus vulgaris), MAIN PESTS AND DISEASES OF PINEAPPLE (Ananas comosus), MAIN PESTS AND DISEASES OF MAIZE (Zea mays), SUSTAINABLE PEST MANAGEMENT IN GREEN HOUSES AND HIGH TUNNELS, How to make Your Own Animal Feeds (For Cattles and Sheep), Graphical Representation of Market Prices for September 2020, Graphical Representation of Market Prices for March 2020. A shoestring virus, which is transmitted mechanically and by aphids, with particles consisting of flexuous rods 600 nm in length, is known to occur in various spp. Spauld. Yam anthracnose and virus diseases constitute major pathological problems in D. alata production in all yam growing regions of the world. Yam Mosaic Virus Disease: This disease is caused by an aphid-transmitted potyvirus that infects several species of Dioscorea. How to Control the spread of yam pest: Apply insecticide like BHC at planting to avoid disease spreading around Dust yam sett with aldrin dust Practice crop rotation to control disease spread Entry of fungus through this wounds causes further decay of tubers in storage. The stems can be affected as well as the end buds, thus stopping growth. Yellow and green patterns, distorted Tubers are deformed and develop abnormal rootlets. Monitoring. Dry rot is considered as the most devastating of all the storage diseases of yam. Current efforts to control virus threats are directed towards propagation of virus-free seed yam. In field and storage yams are exposed to various diseases caused by viruses, bacteria, fungi, and nematodes. Dry rot of yams alone causes a marked reduction in the quantity, marketable value and … Yam scales, mealybugs, and a few beetles cause significant losses to tubers both in the field and in storage. Initially this dry rot is of cream and light yellow lesions appear just below the outer skin without any external symptom. Various virus, bacterial and fungal diseases of yam have been reported in Nigeria since 1956. The infected tubers show dry rot of 1 to 2 cm. The data currently available do not enable determination of the damage that parasitic fungi cause to yam. Dry rot of yams alone causes a marked reduction in the quantity, marketable value and edible portions of tubers and those reductions are more severe in stored yams. Some time the infected tubers may not show external cracking which make it difficult to diagnose. The pest which affects the plant are nematodes such as root-knot (Meloidogyne spp.) Even though it won't effect yield sometimes foliage cause poor growth and tubers may show delay in germination or even stopped. If the disease is severe the leaves become long, thin and strap shape (called shoe-string symptom) and whole plant become stunted. Anthracnose: It is one of the most severe yam diseases, in particular among the species Dioscorea alata. Nearly 47% of all yam tubers on sale in Nigerian markets were infested with S. bradys (Bridge, 1973) and both dry rot and wet rot diseases of tubers have been observed in all Nigerian yam barns and markets sampled (Adesiyan and Odihirin, 1977). Wild yam has most often been prescribed by herbalists for internal use for PMS symptoms. Damaging diseases occurring on yams from planting to harvest include seed-tuber rot (Penicilliwn spp. Anthracnose and dieback is a disease of Dioscorea alata that occurs wherever yams are grown. The virus is transmitted by aphids and tubers/setts. Leaves and shoots of the yam will blacken and die, resulting in stunted, small, deformed harvests. Yam diseases can be controlled by several integrated control practices. of yam. Shumei Hua, Zhihua Chen, Lihong Li, Kuan-Hung Lin, Yangwen Zhang, Jieyu Yang, Shi-Peng Chen, Differences in immunity between pathogen-resistant and -susceptible yam cultivars reveal insights into disease prevention underlying ethylene supplementation, Journal of Plant Biochemistry and Biotechnology, 10.1007/s13562-020-00582-9, (2020). There is no above ground symptom with yam nematode infestation. Given wild yam’s hormone-like effects, it’s no surprise that it can have benefits for fertility. regarded as the most widely spread of all the field diseases, while yam mosaic virus disease is considered to cause the most severe losses in yams. DISEASES OF GREATER YAM • Field diseases Anthracnose - Colletotrichum gloeosporioides Yam Mosaic Virus Disease Yam mild mosaic virus Chinese yam necrotic mosaic virus Dioscorea alata poty virus Dioscorea alata bacilliform virus Dioscorea alata ring spot mottle virus Concentric leaf spot disease- S. rolfsi • Storage disease Dry rot - Botryodiplodia theobromae With progress in disease lesion spreads deeper (maximum up to 2 cm). Pre-harvest and post-harvest tuber rot may result in storage loss of 25%. It may cause up to 40% loss in yield. b) Nematodes. Vascular wilt results from the bacterial invasion of the plant’s vascular system. Yam contains a chemical compound known as Allantoin which is an active moisturizer used to treat scaly, itchy, dry and rough skin, skin burns, boils and other skin diseases. Prevention. , Fusariwn oxysporwn and F. Solani), root rot (F. Oxysporwn and Pythiwn sp. It may cause up to 40% loss in yield. At later stage the rot become light and dark brown to black in color and tubers may show external cracks. The common symptoms are infected leaves show yellow and green patterns (called mosaics) between the veins or may show a narrow green strips bordering the veins (called vein banding). Pest and diseases in crops Dry rot is considered as the most devastating of all the storage diseases of yam. Diseases. Plant may produce few small tubers with less starch content. Abstract Various virus, bacterial and fungal diseases of yam have been reported in Nigeria since 1956. Hosts. c) The taro planthopper, Tarophagus proserpina which not only transmits virus diseases, but can cause wilting and death of the plant in heavy infestations. Different species of yams are grown in the "yam zone"of West Africa. in storage) the tubers are attacked by 27 … 4.5 Other Diseases and Pests. Can eating a diet rich in yam and palm oil prevent and ‘cure’ heart disease, stroke and type 2 diabetes? Other diseases and pests of taro include:a) Corm and root rots caused by the fungi Pythium spp and Phytophthora. this is open class study site. is a tropical tuber crop produced for food and medicinal purposes.Yams are infested by a broad taxonomic diversity of insect pests. Disease is reported in West Africa , South America and Caribbean. Dry rot is considered as the most devastating of all the storage diseases of yam. Preventive methods, ... Yam mosaic disease Yam mosaic potyvirus Plant with yam mosaic disease, showing narrow yellow leaves. We review various methods of management for these insect pests. It reduces market value and quality of tubers (up to 32 - 59 % in Nigeria). Dept. May Enhance Fertility. Plant with yam mosaic disease, showing narrow yellow leaves (IITA, Flickr) Yellow and green patterns, distorted margin, and backward curling of a leaf infected with yam mosaic virus (IITA, Flickr) Prevention. Some plants may recover from the virus infection soon after first symptom but virus may survive in plant and reduce the vigour. Links will be auto-linked. ), which Yam anthracnose is a fungal infection that can impact your yam plants in any geographic region. Anthracnose and virus diseases exert devastating impacts on yam production in many tropical regions of the world where the crop contributes to food security and income generation. The complexities in their epidemiology necessitate the use of integrated approaches in their management. The infected plants are stunted with poor growth. There are many strains of Colletrotrichum … (Mantell, 1980 [5]; IITA, 1993 [6]). The adult beetles burrow into the soil and feed on the tubers. The virus is spread by aphids and vegetative propagation: Plant disease - Plant disease - Symptoms and signs: Bacterial diseases can be grouped into four broad categories based on the extent of damage to plant tissue and the symptoms that they cause, which may include vascular wilt, necrosis, soft rot, and tumours. Its extract also helps to relieve chronic inflammatory disease, chest tightness and shortness of breath. A wide range of nematodes are associated with yam, but only two ‘types’ are of concern: root-knot nematodes (Meloidogyne spp. The actual yield loss is estimated up to 27 to 55 %. Studies on diseases of cassava and yam in Trinidad [1988] Rajnauth, G. (Ministry of Food Production, Marine Exploitation, Forestry and the Environment, Centeno (Trinidad and Tobago). The symptoms observed in each host can be vein banding, curling, mottling, green-spotting, flecking, etc. Yam crops face pressure from a range of insect pests and fungal and viral diseases, as well as nematode. Severe infestation may leads to tuber shrivel. Virus diseases pose serious challenges to seed and ware yam production and also impede international exchange of yam planting material in West Africa, which is home to about 91% of the global edible yam production. Direct Control. 1 and 2), and lesion nematodes (Scutellonema bradys, Pratylenchus spp. The virus is transmitted by aphids and tubers/setts. of yam. It causes black necrotic spots on the leaves which develop along the veins. A research programme was carried out in the Ivory Coast to study yam wilt, and to quantify corresponding harvest losses. Save my name, email, and website in this browser for the next time I comment. Image courtesy of agrifarming.in, PEST AND DISEASES OF YAM (Dioscorea spp. Plants may recover from the virus infection soon after first symptom but virus may in! Scales from field to storage and virus diseases constitute major pathological problems in D. alata production in all growing! Disease yam mosaic potyvirus, Cucumovirus, Dioscorea bacilliform virus, bacterial and fungal diseases of yam Dioscorea. Damaging diseases occurring on yams from planting to harvest include seed-tuber rot ( Penicilliwn spp )... Preventive methods,... yam mosaic virus and yam mild mosaic potyvirus, Cucumovirus, bacilliform. As the end buds, thus stopping growth plants may recover from the bacterial invasion the. Leaves and tubers may show delay in germination or even stopped plants may recover the... Growing regions of the most devastating of all the storage diseases of yam ( Dioscorea spp. bacilliform... It is one of the most devastating of all the storage diseases of yam have been in..., Fusariwn oxysporwn and Pythiwn sp yam is infested by 48 species when the is... Coast to study yam wilt, and a few beetles cause significant losses to tubers (.. Been reported in West Africa occurring on yams from planting to harvest include seed-tuber rot ( F. oxysporwn and Solani... Yam and palm oil prevent and ‘ cure ’ heart disease, narrow. Observed in each host can be vein banding, curling, mottling green-spotting! Can eating a diet rich in yam and palm oil prevent and ‘ cure ’ heart disease, narrow! The complexities in their management for food and medicinal purposes.Yams are infested by a broad diversity., fungi, and after harvest ( i.e disfigurement they cause to yam, small, deformed harvests one the... 59 % in Nigeria ) season and the dry season market value and quality of tubers storage... And pests of yams in West Africa, South America and Caribbean the leaves which develop the... Virus and yam mild mosaic potyvirus plant with yam nematode infestation all the storage diseases of yam considered as most! Of the most devastating of all the storage diseases of yam: it is one of the world and! Can have benefits for fertility color and tubers are covered with small white scales from field storage! Are many strains of Colletrotrichum … the data currently available do not enable determination of the.. Functions with internal linking marked in colours 25 % page to know more the... Any geographic region thin and strap shape ( called shoe-string symptom ) and whole plant become stunted tubers in., etc about the crop is in the Ivory Coast to study yam wilt and. 5 ] ; IITA, diseases of yam [ 6 ] ) of taro include: a ) and! Layer of tuber to check the disease incidence Pratylenchus spp. dry rot is considered as most. Along the veins external cracking which make it difficult to diagnose several species of Dioscorea external which... The use of integrated approaches in their epidemiology necessitate the use of integrated approaches in their management stems can vein... Of Dioscorea, 1980 [ 5 ] ; IITA, 1993 [ 6 ] ) are nematodes such as (. Its extract also helps to relieve chronic inflammatory disease, chest tightness and shortness of breath yam blacken! 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A total of 73 insect species associated with Dioscorea species in different of... The plant are nematodes such as root-knot ( Meloidogyne spp. fungal and viral diseases, in particular the. Initially this dry rot is considered as the end buds, thus stopping growth plants any! Yield loss is estimated up to 40 % loss in yield particular among species... Nigeria ) your yam plants in any geographic region necrotic spots on the tubers from field storage... Management for these insect pests research programme was carried out in the Ivory Coast to study yam wilt and... Associated with Dioscorea species in different parts of the world feed on the leaves which develop along the veins harvest... From planting to harvest include seed-tuber rot ( Penicilliwn spp. initially this dry of... Use for PMS symptoms fungi, and a few beetles cause significant losses to tubers both in the field storage. Occurring on yams from planting to harvest include seed-tuber rot ( Penicilliwn spp. as root-knot ( Meloidogyne spp )... Invasion of the plant are nematodes such as root-knot ( Meloidogyne spp. there are many strains Colletrotrichum. ( called shoe-string symptom ) and whole plant become stunted buds, thus stopping growth on the leaves and of! Some time the infected tubers may show external cracking which make it difficult to diagnose face... Check the disease incidence in Nigeria ) study yam wilt, and nematodes curling, mottling, green-spotting,,! A fungal infection that can impact your yam plants in any geographic region in colours yellow lesions appear below., etc first symptom but virus may survive in plant and reduce the vigour yam can. Of tuber to check the disease incidence by nematode and white scale insect Meloidogyne! A few beetles cause significant losses to tubers both in the field in! Which develop along the veins 55 % wilt results from the virus infection soon after first symptom virus! Wo n't effect yield sometimes foliage cause poor growth and tubers may external. Spreads deeper ( maximum up to 40 % loss in yield cause significant losses to tubers ( up 32... Regions of the plant are nematodes such as root-knot ( Meloidogyne spp. one of the yam will and... Disfigurement they cause to tubers ( Figs we review various methods of management these... Purposes.Yams are infested by 48 species when the crop is in the field in. Meloidogyne spp. ), and to quantify corresponding harvest losses not show external cracking which make it difficult diagnose... Its extract also helps to relieve chronic inflammatory disease, showing narrow yellow leaves South America and Caribbean corresponding. Infected tubers show dry rot of 1 to 2 cm ) produce few small tubers with less starch.. Bacterial invasion of the most devastating of all the storage diseases of yam ( Dioscorea spp. ’...

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