Comunicación corta. Cultivares de algodón con resistencia moderada a African cotton mosaic virus

A 3 year screening of 25 long staple cotton cultivars for resistance to African cotton mosaic virus (ACMoV) conducted in northern Nigeria during the 1999-2001 wet seasons indicated that no cultivar was immune or resistant. Two cultivars, Pima S1 and Pima S4 were moderately resistant (16% infection), four cultivars Pima S2, Pima S3, Giza 45 and Giza 69 were moderately susceptible (31% infection), while the remaining 19 cultivars were highly susceptible. The moderately resistant cultivars are high yielding, have high quality lint characteristics such as crin percentage, bundle strength, and micronaire fineness. They can be used to reduce the menace caused by ACMoV on cotton in Nigeria.Se llevó a cabo durante tres años, durante las estaciones húmedas de los años 1999-2001, en el norte de Nigeria, una búsqueda de resistencia al African cotton mosaic virus (ACMoV) entre 25 cultivares de algodón de fibra larga. Ningún cultivar fue inmune o resistente. Dos cultivares (Pima S1 y Pima S4) fueron moderadamente resistentes (16% de infección), cuatro cultivares (Pima S2, Pima S3, Giza 45 y Giza 69) fueron moderadamente susceptibles (31% de infección) y los 19 cultivares restantes fueron altamente susceptibles. Los cultivares moderadamente resistentes dieron una producción alta y tienen una hiladura de alta calidad. Estos cultivares pueden ser utilizados para reducir la amenaza producida por ACMoV en algodón en Nigeria

Alternative hosts of cassava viruses in Kaduna and Sokoto states, Nigeria

Field surveys were conducted in 2015 wet and 2016 dry seasons to determine the occurrence of alternative hosts of cassava viruses in Kaduna and Sokoto States, Nigeria. Eighteen farms from six local Government Areas namely; Lere, Chikun, Kajuru (Kaduna State), Tureta, Shagari and Tambuwal (Sokoto State) were surveyed. Fifty- four weed samples within and around the farms were collected; Eighteen weeds were identified in wet season while 19 weeds were collected and 18 were identified during dry season. Three viruses were tested; African cassava mosaic virus (ACMV), East African cassava mosaic virus (EACMV) were detected using Triple Antibody Sandwich ELISA and Cassava Congo sequivirus using Double Antibody Sandwich ELISA. In Kaduna State, seven samples were positive to ACMV (38.8%) and four samples were positive to ACMV (22.22%) in wet and dry seasons respectively. One sample was positive to EACMV (5.56%) and mixed infection of ACMV + EACMV (5.56%). Cassava Congo sequivirus was negative in all the samples. In Sokoto State, seven weeds were positive to ACMV (38.89%) and three weeds were positive to ACMV (16.69%) in both wet and dry seasons respectively. Weeds that were identified in both wet and dry seasons were Combretum hispidum (L.) and Euphorbia hirta. Euphorbia hirta (L) was found to be an alternative host to ACMV, EACMV and their co-infection. The identification of Euphorbia hirta as new alternative host has widen the knowledge on viral inoculum. This will help to narrow the gap in spread of the disease

VIRUSES IN WEEDS IN Dioscorea YAM FIELDS IN NIGERIA

The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.La pr\ue9sence de virus dans yam laisse et la pr\ue9sence de mauvaises herbes dans une proximit\ue9 imm\ue9diate avec l\u2019igname champs auraient d\ufb \ueatre divulgu\ue9s de s\u2019associer avec un rendement de tubercules diminu\ue9e. Mais le r\uf4le pr\ue9cis des mauvaises herbes comme h\uf4te alternatif de virus infectant yam n\u2019a pas \ue9t\ue9 syst\ue9matiquement \ue9tudi\ue9. Par cons\ue9quent, les \ue9chantillons de feuilles des mauvaises herbes ont \ue9t\ue9 recueillies lors des relev\ue9s des champs igname Dioscorea en FCT-Abuja et cinq \uc9tats de la zone agro-\ue9cologique savane de Guin\ue9e du Nig\ue9ria en 2009 et 2010 et analys\ue9s par Enzyme-Linked Immuno-absorption Assay (ELISA) et r\ue9action en cha\ueene par polym\ue9rase pour virus. Cinquante-quatre et 70 % des \ue9chantillons pr\ue9lev\ue9s au cours des deux ann\ue9es ont \ue9t\ue9 infect\ue9s par le virus de la mosa\uefque Yam, Cucumber mosaic virus, virus doux de marbrure du ni\ue9b\ue9, virus de mosa\uefque v\ue9niel poivre, Telferia virus de la mosa\uefque, virus de mosa\uefque jaune de ni\ue9b\ue9 et mosa\uefque (DaBV). Les herbes et les virus ont \ue9t\ue9 Hibiscus esculentus Moench (Vitroth\ue8que, CMV et CPMMV), Amaranthus spinosus Linn (CMV, Vitroth\ue8que), Physalis angulata L. (Vitroth\ue8que, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (Vitroth\ue8que, CMV, CPMMV), Ludwigia abyssinica A. Rich (Vitroth\ue8que), culiata L. Galinsoga . (Vitroth\ue8que), Eclipta prosterner Linn (Vitroth\ue8que), Justicia flara Vahl (Vitroth\ue8que, CMV), Euphorbia heterophylla Linn (Vitroth\ue8que, CMV), divaricatum Melanpodium L. (Vitroth\ue8que, CMV) et Saccivlepsis Africana Hubb (Vitroth\ue8que), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (Vitroth\ue8que, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (Vitroth\ue8que), Platostoma Africana P. (Vitroth\ue8que), summtrensis de Conyza Retz (VMC, Vitroth\ue8que, PVMV, TeMV), Chroniolea oduratiu L. R (Vitroth\ue8queCYMV), Mitracarpus villosus D.C(CMV) et Sclerocarpus africanus Jacq (VMC, PVMV, TeMV, mosa\uefque). Les mauvaises herbes autour d\u2019igname peuvent servir des h\uf4tes alternes de virus

In vitro and in vivo antioxidant activities of the leaves of Chrysophyllum albidum

Chrysophyllum albidum G. Don. (Sapotaceae) which is distributed in Nigeria is used for the treatment of yellow fever, malaria, diarrhea, vaginal disorders, etc [1]. The study was aimed at investigating the antioxidant properties using in vitro and in vivo models. The effect of 1,1-diphenyl-2-picrylhydrazyl (DPPH) antiradical activity on ethanol, petroleum ether, ethylacetate, butanol, and water fractions of C. albidum was determined. The ethylacetate fraction was purified in column chromatography which led to the isolation and characterization of a myricetin rhamnoside [2]. The structure was elucidated by NMR and mass spectroscopic techniques. Furthermore, ethanol extract was administered to five groups of eight 04: 311-404 03: 207-308 | E10 02: 107-204 01: 1-100 rats per group.The positive control animals were administered with vehicle on the first four days, and with the vehicle and CCl4 on the fifth, sixth and seventh day [3]. The animals in the treatment category were respectively administered (by gastric intubation) with 500, 1000 and 1500mg/kg bw of extract & distilled water for the first four days, and with distilled water, extract and CCl4 on the last three days. Animals were anaesthetized and blood samples were collected for some antioxidant assays. Petroleum ether fraction showed the least antiradical activity (4057.5±809.6g/kg) while ethyl ether fraction exhibited the highest activity (414.4±92.0g/kg). Myricetin rhamnoside also exhibited an excellent radical scavenging activity (314.1±60.2). C. albidum exhibited significant (p<0.05) differences on the activity of malondialdehyde, catalase, and reduced gluthathione. The plant therefore possesses antioxidant activities and could be employed as natural antioxidant boosters

Antioxidant activities of the leaves of Chrysophyllum Albidum G.

Chrysophyllum albidum G. is a tropical plant and commonly found in Nigeria. It belongs to the sapotaceae family and used in folklore in the treatment of yellow fever, malaria, diarrhea, vaginal and dermatological infections. The study was aimed at investigating the antioxidant properties of this plant by employing the in vitro and in vivo experimental models. The effect of DPPH free radical scavenging activity on the fractions of petroleum ether, ethanol, butanol, ethylacetate, and water of C. albidum was determined. The ethyl acetate fraction was purified in colunm chromatography to obtain myricetin rhamnoside. Structure elucidation was done by NMR and mass spectroscopic techniques. Furthermore, ethanol extract was administered to five groups of eight rats per group. The animals in the normal group were administered with vehicle alone for 7 days. The positive control animals were given vehicle on the first four days, and with the vehicle and hepatotoxin (CCl4) on the fifth, sixth and seventh day. The animals in the treatment category were respectively administered with 500, 1000 and 1500 mg/kg b.w. of extract &amp; distilled water for the first four days, and with distilled water, extract and CCl4 on the last three days. Animals were subsequently anaesthetized and blood samples were collected for catalase (CAT), malondialdehyde (MDA), reduced gluthathione (GSH) and superoxide dismutase (SOD) assays. The petroleum ether fraction showed the least antiradical activity (4057.5 ± 809.6 g/kg) while ethyl ether exhibited the highest activity (414.4 ± 92.0 g/kg). Myricetin rhamnoside also exhibited an excellent radical scavenging activity (314.1 ± 60.2) which was comparable to the positive control. Result from animal study showed that C. albidum exhibited significant (p &lt; 0.05) differences on the activity of CAT, MDA and GSH. The plant could therefore be employed as sources of natural antioxidant boosters and for the treatment of some oxidative stress disorders in which free radicals are implicated

Comunicación corta. Incidencia del virus del mosaico del kimbombó en el norte de Nigeria y evidencias de su transmisión por escarabajos

A two year survey was conducted in 2003 and 2004 in okra (Abelmoschus esculentus) plants for Okra mosaic virus (OkMV; genus Tymovirus) symptoms at three locations in northern Nigeria. It showed that the highest incidence of OkMV occurred at Samaru (16.50 and 17.10% in 2003 and 2004, respectively), followed by Shika (13.02 and 14.82%) and Bomo (12.31 and 8.10%). Disease severity followed the same trend. Beetles of Podagrica spp. naturally infected were efficient vectors in the transmission of OkMV.En 2003 y 2004 se llevó a cabo una prospección de síntomas del virus del mosaico del kimbombó (OkMV, género Tymovirus) en plantas de kimbombó (Abelmoschus esculentus) en tres localidades del norte de Nigeria. La incidencia de OkMV más alta se detectó en Samaru (16,50 y 17,10% en 2003 y 2004, respectivamente), seguido de Shika (13,02 y 14,82%) y Bomo (12,31 y 8,10%). En las tres localidades la severidad de la enfermedad siguió la misma tendencia. Escarabajos de Podagrica spp. naturalmente infectados fueron vectores eficientes en la transmisión de OkMV

Viruses in weeds in Dioscorea yam fields in Nigeria

The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses.The presence of viruses in yam leaves and the presence of weeds in close proximity to yam fields have been shown to be associated with diminished tuber yield. But the precise role of weeds as alternative hosts of viruses infecting yam has not been systematically studied. Therefore, leaf samples of weeds were collected from Dioscorea yam fields in FCT-Abuja, and five States of the Guinea Savanna agro-ecological zone of Nigeria in 2009 and 2010, and analysed by Enzyme-Linked Immuno-absorbance Assay (ELISA) and Polymerase Chain Reaction for viruses. Fifty-four and 70% of samples collected during the two years, respectively, were infected with Yam mosaic virus, Cucumber mosaic virus, Cowpea mild mottle virus, Pepper venial mosaic virus, Telfeiria mosaic virus, Cowpea yellow mosaic virus and Badnavirus (DaBV). The weeds and viruses were Hibiscus esculentus Moench (YMV, CMV and CPMMV), Amaranthus spinosus Linn (CMV, YMV), Physalis angulata L (YMV, CMV), Procumbane Linn (CMV), Phyllanthus amarus Shum (YMV, CMV, CPMMV), Ludwigia abyssinica A. Rich (YMV), Galinsoga culiata L. (YMV), Eclipta prostrate Linn (YMV), Justicia flara Vahl (YMV, CMV), Euphorbia heterophylla Linn (YMV, CMV), Melanpodium divaricatum L. (YMV, CMV) and Saccivlepsis Africana Hubb (YMV), Melanpodium divaricatum L. (CPMMV), Crotalaria rutusa L. (YMV, CMV), Aspelia bussei O. Hoffin (CPMMV), Aneilema acquinotide P. Beauv (CPMMV), Pueraria phaseloides Linn (YMV), Platostoma Africana P. (YMV), Conyza summtrensis Retz (YMV, BCMV, PVMV, TeMV), Chroniolea oduratiu L. R (YMV, CYMV), Mitracarpus villosus D.C(CMV) and Sclerocarpus africanus Jacq (BCMV, PVMV, TeMV, Badnavirus). Weeds surrounding yam plants may serve as alternative hosts of viruses