Identification of seed-borne fungi of farmer-saved seeds of pepper and their control with some selected botanicals

A survey was conducted on the source of planting materials and pre-planting seed treatment practice by pepper farmers in Obenemasi and Ofoase-Kokoben communities in the Ashanti Region of Ghana using a well-structured questionnaire in June, 2011. Seed health test was conducted on 40 farmer-saved pepper seed samples collected from the farmers interviewed using the blotter method in the laboratory. Efficacy of garlic, ginger and neem botanical extracts in managing the seed-borne fungi of pepper seeds was also investigated in this study in-vitro. Results of the questionnaire-based survey indicated that, majority of respondent farmers, about 75% recycled seeds from previous harvest, 20% of respondents also used seeds obtained from friends and 5% obtained their pepper seeds from local markets. Nine genera of fungi including 12 species were identified from the pepper seed samples collected. The three botanical extracts proved effective as Mancozeb in controlling one or more of the test seed-borne fungi. Garlic aqueous extract (60% (w/v)) was effective as Mancozeb in controlling Colletotrichum capsici and Colletotrichum gloesporioides. Ginger aqueous extract (60% (w/v)) was also effective against seed-borne Fusarium and Aspergillus spp. whereas aqueous neem extract (60% (w/v)) was effective in controlling Aspergillus flavus and Aspergillus niger

Inoculum Concentration of Armillaria mellea in the Rhizosphere of Intercropped Teak Plantation: the case of the Opro Forest Reserve, Ghana

Teak (Tectona grandis Linn. F.) is the most planted timber tree species in Ghana, with over 73,916 hectares of plantation established at the end of 2008. Many of the teak plantations established in the semi-deciduous forest zones were done using the taungya system with various intercrops. Symptoms of Armillaria (Vahl: Fr.) root-rot of teak have been reported in the taungya plantations, especially in the semi-deciduous forest zones. The study aimed to determine inoculum concentrations of Armillaria mellea in the rhizosphere soil of intercropped teak and compare with sole teak plantation. Mycoflora were isolated from rhizosphere soil of teak intercropped with pepper, okra, maize, yam or cassava at year one to year three sapling stage. Dilution plate technique was used for mycoflora isolation and dilution factor of 10-3 was inoculated on potato dextrose agar amended with chloramphenicol (25mg/l) and incubated at 280C for 14 days after which A. mellea colonies were identified and counted. More A. mellea (Vahl: Fr.) colonies were isolated from rhizosphere soils of intercropped teak plantations than non-intercropped. Differences in A. mellea colonies were more significant amongst intercrops than amongst age of teak plantation at (P ≤ 0.05). There were significantly (P ≤ 0.05) higher numbers of A. mellea colonies in rhizosphere soils of teak intercropped with cassava compared with other intercrops. Number of A. mellea colonies in rhizosphere soils of intercropped teak did not have linear relation with age of teak plantation. Intercropping could promote Armillaria root rot of teak especially with cassava as intercrop

Search for Scutellonema bradys resistance in yams (Dioscorea spp.)

A study to examine variability in susceptibility of yams to Scutellonema bradys and to identify possible sources of resistance in Ghanaian yam germplasm (Dioscorea spp.) for use in yam improvement programmes, particularly, in West Africa was undertaken. Pot and field screening methodologies were used. In general, S. bradys and dry rot of tuber symptoms as well as tuber cracking increased during the storage period. The study showed a positive correlation between visual nematode damage and population densities in yam tubers. There was also a linear relationship between dry rot disease and tuber cracking at harvest and during storage. This confirms that S. bradys causes dry rot of tubers resulting in external cracking of yam tubers. Positive linear relationship was also observed between yam tuber weight loss and dry rot disease indicating that dry rot disease may have contributed to the tuber weight loss. Therefore, tuber dry rot symptoms caused by S. bradys of yams could be used to discard susceptible yams at harvest and after a period of storage. However, there was no linear relationship between nematode population densities in yam tubers and roots, therefore, a root protocol cannot be used for assessing resistance in yams as it could lead to misclassification. The yam germplasm screened, reaffirmed resistance to S. bradys in Dioscorea dumetorum var. Nkanfo and D. cayenensis var. Afun

Evaluation of tomato genotypes for resistance to root-knot nematodes

Tomato ( Solanum lycopersicum ) is one of the most popular vegetable crops worldwide, owing to its high nutritive value and diversified use. Tomato production in Ghana is threatened by plant parasitic nematodes, especially the root knot nematodes ( Meloidogyne spp.), which are responsible for huge economic yield losses. The losses, however, can be averted through use of resistant varieties. A study was conducted to evaluate tomato genotypes reaction to root-knot nematodes. Five inoculum levels, 100, 500, 1000, 1500 and 2000 root-knot nematode eggs per 1.6 litres of soil per pot were inoculated on tomato seedlings. A total of 33 genotypes were screened for resistance to Meloidogyne spp. Nine tomato genotypes were collected from Burkina Faso, eight from Vietnam, seven from the United States of America, three genotypes from South Africa, and six from local agro-dealers and farmers in Ghana. The genotypes were screened in pots and the field for host resistance to Meloidogyne spp. The 1500 eggs per plant inoculation level resulted in the highest number of eggs, juveniles and fresh root weight. Among the 33 genotypes screened, Tomato Mongal T-11 and Tomato Beef Master were found to be highly resistant to Meloidogyne spp. and also recorded the lowest reproductive factors of 0.71 and 0.53, respectively.La tomate ( Solanum lycopersicum ) est une des plus populaires l\ue9gumes au monde suite \ue0 sa valeur plus nutritive et utilisation diversifi\ue9e. Par ailleurs, sa production est limit\ue9e par des n\ue9matodes parasites des plantes, sp\ue9cialement les galles racinaires ( Meloidogyne spp.) et sont responsables de lourdes pertes \ue9conomiques. Ces pertes, par ailleurs, peuvent \ueatre \ue9vit\ue9es par l\u2019utilisation des vari\ue9t\ue9s r\ue9sistantes. Une \ue9tude \ue9tait conduite pour \ue9valuer la r\ue9action des g\ue9notypes de tomates aux galles racinaires des n\ue9matodes. Cinq niveaux d\u2019inoculum \ue0 savoir 100, 500, 1000, 1500 et 2000 galles d\u2019oeufs de n\ue9matodes par 1.6 litres de sol par pot \ue9taient inocul\ue9s sur les plantules de tomates. Un total de 33 g\ue9notypes \ue9taient r\ue9sistants au Meloidogyne spp. Neuf g\ue9notypes de tomates \ue9taient collect\ue9s du Burkina Faso, huit du Vietnam, sept des Etats Unis d\u2019Am\ue9rique, trois g\ue9notypes d\u2019Afrique du Sud et six provenant des vendeurs et fermiers locaux du Ghana. Les g\ue9notypes \ue9taient test\ue9s en pots et en champ pour r\ue9sistance de l\u2019 h\uf4te au Meloidogyne spp. Les 1500 oeufs par niveau d\u2019inoculation de plants ont induit un nombre le plus \ue9lev\ue9 d\u2019oeufs, raciness juveniles et le poids des racines fra\ueeches. Parmi les 33 g\ue9notypes test\ue9s, Tomato Mongal T-11 et Tomato Beef Master ont \ue9t\ue9 trouv\ue9s les plus r\ue9sistantes au Meloidogyne spp. et avaient aussi enregistr\ue9 les facteurs les moins reproductifs de 0.71 and 0.53, repectivement

Occurrence of cowpea viruses in the forst and savannah agro-ecological zones of Ghana

Cowpea ( Vigna unguiculata (L.) Walp) is a major grain legume in Sub Saharan Africa whose production is heavily affected by viral diseases. A disease survey and antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA) were used to determine the incidence, severity and occurrence of viruses infecting cowpea in some major growing areas in the Ashanti and Brong Ahafo regions of Ghana. The survey revealed the highest virus incidence (81.6%) and severity (3.01) in Ejura, and the least incidence (46.7%) and severity (2.38) in Nkoranza. The ACP-ELISA results indicated that Blackeye cowpea mosaic virus (BICMV) was the most prevalent virus, with occurrence ranging from 32% in Mampong to 60% in Atebubu. Cucumber mosaic virus (CMV) was the least detected, occurring only in samples from Nkoranza (4%). Cowpea mild mottle virus (CPMMV), Cowpea mottle virus (CPMoV), Southern bean mosaic virus (SBMV), Cowpea aphid borne mosaic virus (CABMV) and Cowpea yellow mottle virus (CYMV) were also detected in the samples. The prevalence of these viruses suggest the need for continuous monitoring of cowpea fields in the country to ensure effective disease management.Le ni\ue9b\ue9 ( Vigna unguiculata (L.) Walp) est une l\ue9gumineuse \ue0 grains majeure en Afrique SubSaharienne dont la production est fortement affect\ue9e par les maladies virales. Une enqu\ueate sur la maladie et un test d\u2019immunosorbant enzymatique sur plaque rev\ueatue d\u2019antig\ue8ne (ACP-ELISA) ont \ue9t\ue9 utilis\ue9s pour d\ue9terminer l\u2019incidence, la gravit\ue9 et la fr\ue9quence des virus infectant le ni\ue9b\ue9 dans certaines grandes zones de culture des r\ue9gions d\u2019Ashanti et de Brong Ahafo au Ghana. L\u2019enqu\ueate a r\ue9v\ue9l\ue9 l\u2019incidence du virus (81,6%) et la gravit\ue9 (3,01) les plus \ue9lev\ue9es \ue0 Ejura, et la moindre incidence (46,7%) et la gravit\ue9 (2,38) \ue0 Nkoranza. Les r\ue9sultats ACP-ELISA ont indiqu\ue9 que le virus de la mosa\uefque du ni\ue9b\ue9 aux yeux noirs (BICMV) \ue9tait le virus le plus r\ue9pandu, avec une occurrence allant de 32% \ue0 Mampong \ue0 60% \ue0 Atebubu. Le virus de la mosa\uefque du concombre (CMV) a \ue9t\ue9 le moins d\ue9tect\ue9, et il ne s\u2019est que\ua0pr\ue9sent\ue9 dans des \ue9chantillons de Nkoranza (4%). Le virus de la marbrure l\ue9g\ue8re du ni\ue9b\ue9 (CPMMV), le virus de la marbrure du ni\ue9b\ue9 (CPMoV), le virus de la mosa\uefque du haricot m\ue9ridional (SBMV), le virus de la mosa\uefque du puceron du ni\ue9b\ue9 (CABMV) et le virus de la marbrure jaune du ni\ue9b\ue9 (CYMV) ont \ue9galement \ue9t\ue9 d\ue9tect\ue9s dans les \ue9chantillons. La pr\ue9valence de ces virus sugg\ue8re la n\ue9cessit\ue9 d\u2019une surveillance continue des champs de ni\ue9b\ue9 dans le pays pour assurer une gestion efficace de la maladie

Evaluation of tomato genotypes for resistance to root-knot nematodes

Tomato ( Solanum lycopersicum ) is one of the most popular vegetable crops worldwide, owing to its high nutritive value and diversified use. Tomato production in Ghana is threatened by plant parasitic nematodes, especially the root knot nematodes ( Meloidogyne spp.), which are responsible for huge economic yield losses. The losses, however, can be averted through use of resistant varieties. A study was conducted to evaluate tomato genotypes reaction to root-knot nematodes. Five inoculum levels, 100, 500, 1000, 1500 and 2000 root-knot nematode eggs per 1.6 litres of soil per pot were inoculated on tomato seedlings. A total of 33 genotypes were screened for resistance to Meloidogyne spp. Nine tomato genotypes were collected from Burkina Faso, eight from Vietnam, seven from the United States of America, three genotypes from South Africa, and six from local agro-dealers and farmers in Ghana. The genotypes were screened in pots and the field for host resistance to Meloidogyne spp. The 1500 eggs per plant inoculation level resulted in the highest number of eggs, juveniles and fresh root weight. Among the 33 genotypes screened, Tomato Mongal T-11 and Tomato Beef Master were found to be highly resistant to Meloidogyne spp. and also recorded the lowest reproductive factors of 0.71 and 0.53, respectively.La tomate ( Solanum lycopersicum ) est une des plus populaires légumes au monde suite à sa valeur plus nutritive et utilisation diversifiée. Par ailleurs, sa production est limitée par des nématodes parasites des plantes, spécialement les galles racinaires ( Meloidogyne spp.) et sont responsables de lourdes pertes économiques. Ces pertes, par ailleurs, peuvent être évitées par l’utilisation des variétés résistantes. Une étude était conduite pour évaluer la réaction des génotypes de tomates aux galles racinaires des nématodes. Cinq niveaux d’inoculum à savoir 100, 500, 1000, 1500 et 2000 galles d’oeufs de nématodes par 1.6 litres de sol par pot étaient inoculés sur les plantules de tomates. Un total de 33 génotypes étaient résistants au Meloidogyne spp. Neuf génotypes de tomates étaient collectés du Burkina Faso, huit du Vietnam, sept des Etats Unis d’Amérique, trois génotypes d’Afrique du Sud et six provenant des vendeurs et fermiers locaux du Ghana. Les génotypes étaient testés en pots et en champ pour résistance de l’ hôte au Meloidogyne spp. Les 1500 oeufs par niveau d’inoculation de plants ont induit un nombre le plus élevé d’oeufs, raciness juveniles et le poids des racines fraîches. Parmi les 33 génotypes testés, Tomato Mongal T-11 et Tomato Beef Master ont été trouvés les plus résistantes au Meloidogyne spp. et avaient aussi enregistré les facteurs les moins reproductifs de 0.71 and 0.53, repectivement

Fungal Organisms Associated with Post-harvest Rot of Frafra Potatoes [Solenostemon rotundifolius (Poir.)] in Bongo-Soe, Upper East Region, Ghana

Aims: The study aims to identifying the microorganisms associated with post-harvest rot of frafra potatoes in Bongo-soe, Upper east region of Ghana. Place and Duration of Study: Department of Horticulture and the Pathology laboratory of the Faculty of Agriculture, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana. The Solenostemon rotundifolius tubers were stored at the Horticulture Department laboratory whiles rot identification was carried out at the Pathology laboratory of the Faculty of Agriculture. The Tubers were stored from 2nd November, 2012 to 22nd March 2013. Methodology: Four hundred (400) tubers of black cultivar and four hundred (400) tubers of a brown cultivar of Solenostemon rotundifolius tubers showing visible signs of rot during the storage were collected. Pieces of diseased tissues from the margin of the necrotic collected and immersed in 10% commercial bleach solution for sterilisation, for one minute. These were then blotted dry and plated on Potato Dextrose Agar PDA. The plates were sealed with a cellotape until growth occurred. Results: The microorganisms identified to be responsible for causing rot in Solenostemon rotundifolius tubers were six in number. Colletotrichum gloeosporioides was identified to be responsible for 30.76% of rots observed, followed by Aspergillus niger, 23.07%, Curvularia lunata, 19.23%, Aspergillus flavus, 11.54%, Trichoderma sp and Penicillium sp both recorded 7.70% of rots observed. The percentage incidence of Aspergillus niger (15.38%), Curvularia lunata (11.54%) and Aspergillus flavus (7.69%) was higher in the black cultivar as compared with the brown cultivar which had percentage incidence of 7.69%, 7.69% and 3.85% respectively. Also, the percentage incidence of Colletotrichum gloeosporioides (15.38%) and Penicillium sp (3.85%) was the same in both the black and brown cultivars of Solenostemon rotundifolius tubers used in this study. Conclusion: The activities of the damaging microorganisms can be reduced by controlling mechanical injury during harvesting, transportation and storage of Solenostemon rotundifolius tubers should be prevented or reduced because they pave the way for tuber infection by the rot causing microorganisms

CAPS markers TAO1 and TG105 in the identification of I2 resistant gene in Nigerian accessions of tomato, Solanum lycopersicum L.

Fusarium oxysporum (f.sp). lycopersici (Fol) is a soil-borne fungus that inhabits most tomato-growing regions of the world, causing vascular wilt disease. In Nigeria, the disease constitutes close to 40% loss in tomato yield annually. Cleaved Amplified Polymorphic Sequence (CAPS) markers TAO1 and TG105, developed elsewhere, were used to identify tomato accessions possessing the gene (I2) which confers resistance to Fol race 2. In this work, fifty Nigerian accessions of tomato, Solanum lycopersicum L., were screened with the two CAPS markers for resistant I2 gene. The primer pairs for TAO1 and TG105 produced amplification at 902 bp in 33 accessions and 450 bp in 38 accessions, respectively. The restriction enzymes Fok1 and Hinf1, for TAO1 and TG105 respectively, produced fragments at base pairs indicative of susceptible, homozygous and heterozygous resistant accessions to Fol. Restriction fragments from the two markers indicated that 11 accessions were homozygous resistant to Fol. Four of these accessions (Delila, Gem Pride, K-Small and Oxheart) occurred in the two molecular markers as homozygous resistant to Fol. The combined effect of the two markers enhanced precision in the identification of tomato accessions with resistance status to Fusarium vascular wilt.Keywords: CAPS markers, Fusarium wilt, I2 gene, tomato accession