You may use , Click here to go to the topics page to know more about the crop. Pre-harvest and post-harvest tuber rot may result in storage loss of 25%. Damaging diseases occurring on yams from planting to harvest include seed-tuber rot (Penicilliwn spp. 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. Leaves and shoots of the yam will blacken and die, resulting in stunted, small, deformed harvests. A wide range of nematodes are associated with yam, but only two ‘types’ are of concern: root-knot nematodes (Meloidogyne spp. 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). ), which are evident by the disfigurement they cause to tubers (Figs. If the disease is severe the leaves become long, thin and strap shape (called shoe-string symptom) and whole plant become stunted. Direct Control. Information provided by https://coleacp.org. The complexities in their epidemiology necessitate the use of integrated approaches in their management. 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. Their growth and dormant phases correspond respectively to the wet season and the dry season. Severe infestation may leads to tuber shrivel. Yam crops face pressure from a range of insect pests and fungal and viral diseases, as well as nematode. Yam diseases can be controlled by several integrated control practices. May Enhance Fertility. Wild yam has most often been prescribed by herbalists for internal use for PMS symptoms. It reduces market value and quality of tubers (up to 32 - 59 % in Nigeria). The infected plants are stunted with poor growth. 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 The data currently available do not enable determination of the damage that parasitic fungi cause to yam. (Mantell, 1980 [5]; IITA, 1993 [6]). 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. Yam anthracnose disease is caused by Colletotrichum gloesporioides Penz. Links will be auto-linked. For maximum yield, the yams require a humid tropical environment, with an annual rainfall over 1500 mm distributed uniformly throughout the growing season. 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 It may cause up to 40% loss in yield. Yam is infested by 48 species when the crop is in the field, and after harvest (i.e. in storage) the tubers are attacked by 27 … 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. At later stage the rot become light and dark brown to black in color and tubers may show external cracks. 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). its all about life of Plant Pathology) Pegus, J.E. 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). Central Exp. Yam Mosaic Virus Disease: This disease is caused by an aphid-transmitted potyvirus that infects several species of Dioscorea. Diseases. The symptoms observed in each host can be vein banding, curling, mottling, green-spotting, flecking, etc. Tubers are deformed and develop abnormal rootlets. 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). Dry rot is considered as the most devastating of all the storage diseases of yam. 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. Disease is reported in West Africa , … Yam scales, mealybugs, and a few beetles cause significant losses to tubers both in the field and in storage. Monitoring. Various virus, bacterial and fungal diseases of yam have been reported in Nigeria since 1956. is a tropical tuber crop produced for food and medicinal purposes.Yams are infested by a broad taxonomic diversity of insect pests. 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. Initially this dry rot is of cream and light yellow lesions appear just below the outer skin without any external symptom. The leaves turn yellow in color. Can eating a diet rich in yam and palm oil prevent and ‘cure’ heart disease, stroke and type 2 diabetes? We reviewed a total of 73 insect species associated with Dioscorea species in different parts of the world. Some plants may recover from the virus infection soon after first symptom but virus may survive in plant and reduce the vigour. Pests and diseases of yam and their control methods Pests of Yam Yam tuber pests makes holes on tubers, resulting in low tuber marketability. Different species of yams are grown in the "yam zone"of West Africa. In field and storage yams are exposed to various diseases caused by viruses, bacteria, fungi, and nematodes. Even though it won't effect yield sometimes foliage cause poor growth and tubers may show delay in germination or even stopped. 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. 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