Search Results (6)

The Kponan yam (Dioscorea cayenensis-rotundata) is a culturally and economically important crop in Côte d’Ivoire but faces significant post-harvest losses, reducing farmers’ and traders’ incomes. This study aimed to identify strategies to minimize these losses during storage. To this end, Kponan yams from Bondoukou, Bouna, and Kouassi-Kouassikro, key production areas, were grown in experimental plots and monitored over three months in both field and warehouse storage. The results showed that yams harvested in Kouassi-Kouassikro (2.53 ± 0.06 kg) and Bondoukou (2.37 ± 0.09 kg) were heavier than those from Bouna (2.01 ± 0.11 kg). Storage conditions influenced spoilage: yams stored in pits had lower alteration rates (40.00% to 48.57%) compared to those stored under straw huts or trees (100%). In warehouses, alteration rates ranged from 72.29% (Bondoukou) to 100% (Kouassi-Kouassikro), with rot rates varying from 47.05% to 70.00%, respectively. Weight losses varied from 15.15% to 36.67% in warehouses versus 8.47% to 42.86% in field storage. These results underline the importance of storage methods, with pit storage significantly reducing deterioration. Full article

Foshou yam (Dioscorea esculenta) is a tuber food crop in China. It is a rare species of the yam family and known for its high nutritional value. From 2019 to 2021, tuber rot was observed in Foshou yam in Wuxue, Hubei Province, China. Fungal strains were isolated from diseased tubers, and ten representative strains were identified based on microscopical characterization and multi-locus phylogenetic analysis. A total of five different species were identified, including Curvularia geniculata, Curvularia muehlenbeckiae, Fusarium commune, Penicillium oxalicum, and Penicillium sclerotigenum. Pathogenicity test revealed that these fungi are the pathogens of tuber rot in Foshou yam. Among them, P. oxalicum exhibited the strongest pathogenicity. To our knowledge, this is the first report of tuber rot in D. esculenta caused by these five species worldwide. This study provides important information for the future management of tuber rot in Foshou yam. Full article

Yam (Dioscorea spp.) is an important tuber crop consumed globally. However, stable yam production faces challenges from a variety of diseases caused by fungi, nematodes, viruses, and bacteria. Prominent diseases such as anthracnose, leaf spot, yam wilt, dry rot, and crazy root syndrome, currently pose serious threats to yam yields. These diseases not only result in quality degradation but also cause great economic losses. This review summarizes the damages, symptoms, causal agents, and epidemic factors of major yam diseases. It also outlines a comprehensive disease control strategy that includes the use of resistant varieties, proper crop rotation, sanitation measures, and the application of agrochemicals and biocontrol agents. Additionally, this review addresses future perspectives on risk factors and knowledge gaps, aiming to serve as a reference for in-depth research into advanced disease monitoring and control technologies for yams. Full article

Field and storage trials were conducted to assess the response of exotic and local yam genotypes to major diseases (anthracnose, yam mosaic virus (YMV) and dry rot) and pests (i.e., mealy bug and nematodes) for the identification of parents with desired complementary traits for crossing. The experiment was conducted at the Njala Agricultural Research Centre (NARC) experimental site in Sierra Leone during two cropping seasons, 2020 and 2021. A total of 113 genotypes of yam comprising 15 D. rotundata, 4 D. prahensilis, 7 D. esculenta, 74 D. alata, 7 D. bulbifera, and 4 D. cayenensis were assessed. Results showed a significant (p < 0.001) linear relationship between yield and disease severity among yam genotypes. In-field disease (anthracnose and yam mosaic virus) infection accounted for 38% of the total variation observed in the fresh tuber yield. Findings on fresh tuber yield revealed that for every ton increase in yield of yams, anthracnose and YMV severities at five months after planting (MAP) decreased by 0.5 and 3.1 units, respectively. About 30 genotypes had low infection of disease, of which two belonged to D. rotundata (TDr 205 and TDr 96/00587), two belonged to D. prahensilis (PSLY074-13 and BMSLY085-13), three belonged to D. bulbifera (MOSLY022-12, MOSLY024-12 and KESLY09-12), and one belonged to D. esculenta (WRSLY083-13), while the remaining were D. alata. About 27 genotypes had intermediate infection, and 14 had high disease susceptibility, all of which belonged to D. alata. Storage disease infection had a highly significant (p < 0.002) linear relationship among yam genotypes. Dry rot, mealy bug, and nematode infection accounted for 15.1% of the total variation in fresh tuber weight loss. The findings were relevant for selecting parents with complementary traits of interest targeted at yam population improvement. Full article

Elytroteinus geophilus (Lucas) is a polyphagous weevil that is widespread in the South Pacific islands and is known to cause damage to various crops with large nutrient storage structures such as kava, ginger, yellow passion fruit, yams and sweet potatoes. More significantly, E. geophilus, the Fijian Ginger Weevil, has been linked, along with two wound invading fungal pathogens, to a passion fruit collar rot in Samoa. This species is considered a high-risk insect pest and it is included in the USDA’s prioritized offshore pest list. We report on new plant hosts and behavior of this weevil. The first new host record resulted from interception of this weevil in bulbs of Tropical Spider Lily (Crinum sp.) in Alabama. This interception initiated an examination of museum specimens and the literature that resulted in a second previously unreported host record (vanilla (Orchidaceae)) and a new behavioral trait for this weevil: the use of plant fibers to spin a cocoon for pupation. A synthesis of known host plants records is reported here and suggests a preference by this weevil of starch-storing plant organs. A distribution map and a differential diagnosis of the species is also provided. Full article

Yam farmers in Ghana have, over the years, used herbicides for weed control, particularly glyphosate. Although this has been helpful to them, there are complaints and concerns, among the yam farmers and a section of the public, that the yam tuber rots easily under the use of herbicides. This study, therefore, was set up at the field level to investigate the possibility of herbicides use causing yam rot. Two yam varieties, “laribako” and “olodo”, were grown under the conditions of chemical weed control (use of glyphosate) and manual weed control in three replicate sites in Wulensi in the Nanumba traditional area of northern Ghana. The study revealed that there was no difference in rots between herbicide treated yams and manually weeded yams, but that there was a difference in rots between “laribako” and “olodo” yam varieties. The results also showed that there was no difference in yield between herbicide treated yams and manually weeded yams. Based on the findings, it can be concluded that, there was no difference in yam rot and yield between herbicides treated and manually weeded yams, but “laribako” was more susceptible to rot than “olodo”. Full article