The effect of 3 organic soil amendments viz., cassava peel (Manihot esculenta, Cranz), sawdust (Gmelina arborea, Roxb) and leaves of (Cedrela odorata, L) on the stalk rot of maize (Zea mays L.) caused by Fusarium verticillioides was investigated. Fourteen treatments made up of single or combined treatments with pathogenic or non-pathogenic inoculation of concentrations 3:1, 2:2 and 1:3 were added to 15.8 g sterilized soil. Growth parameters data on leaf numbers, stem girth, plant height and leaf area were collected biweekly. All treatments had significant effects on plant heights, number of leaves, leaves areas, stems girths and on disease indices and disease severities of the treated plants compared to controls. Concentration 2 (2:2) had the highest effect on all the growth parameters considered and gave the lowest disease index (P= 0.05, R2= 0.98) and disease severity (P= 0.05, R2= 0.92) in the treated plants. Plants treated with cassava peels combined with C odorata had significantly lowest disease index and severity thus, competing favourably with F verticillioides. Severity of stalk rot of maize can reduce significantly in amended soils compared to unamended soils. Key word: Organic amendment, stalk rot, F verticillioides, toothpick inoculation, maize stem, Gmelina arborea, Manihot esculenta, Cederela odorata.

A virus-infected leaf of Mucuna pruriens was collected and tested for an incidence of a virus through biological properties using various plant host range inoculation tests, longevity-in-vitro, dilution-endpoint, thermal-inactivation point and electron microscopy. Results of host range inoculation tests showed the following plant species to be susceptible to the virus; Nicotiana tabacum, N. rustica, N. benthamiana, N. glutinosa, N. occidentalis, N. Sylvesris (Speg and Comes) and others. No plant in the family Convolvulacaee, Cucurbitaceae was found to be infected with the virus. However Chenopodium quinoa and C. murale in the family Chenopodiaceae were infected with symptoms of mottling and necrotic lesions. In the family Fabaceae, hybrid cowpea line TVu 76, IT84S – 2114 were infected with mosaic, leaf crinkling and severe leaf curl respectively. The virus had a dilution-end-point of 10-6-10-7, thermal-inactivation-point of 95°C in crude sap of TVu 76. The virus is of agricultural importance because of its incidence on seed coats of legumes which are freely exchanged between agricultural stakeholders.

•Maize ear rot caused by Fusarium verticillioides is a major disease associated with reduced grain yield and ear quality.•Role of biochar as an eco-friendly substitute for Fungicide in the management of maize ear rot is yet to be established.•Each biochar type showed similar severity rate as fungicide (4–10 %), compare to control (11–25 %) and F. verticillioides (26–50 %) treated plants.•Biochar and sawdust act as soil conditioner and significantly managed the resident soil pathogen.

This study investigated phenol production in five maize varieties in response to infection caused by Fusarium verticillioides. Pure culture of the pathogen was obtained from Plant Pathology Laboratory of the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. The screen house experiment was laid out in a completely randomized design. Dual inoculation was done where soil was infected separately before planting and seedlings were infected separately two weeks after planting with two volumes (10ml and 20ml) containing 1.4×107 spores/ml suspension of F. verticillioides. The maize plants were harvested at 4th, 5th and 6th weeks after inoculation and the maize plants were dried at room temperature before determination of phenol content in each of the varieties. Data gathered on the agronomic parameters and phenol contents were subjected to analysis of variance (ANOVA) using SAS 9.1 statistical package. All the maize varieties recorded more than 70% stalk rot incidence while the severity ranged from 19.01% in variety ART-98-SW1 to 25.21% in ART-98-SW6. ART-98-SW6 showed the most (p<0.05) phenol content (21.28 mg/g). Soil inoculation produced the highest percentage stalk rot severity while seedling inoculation showed significantly higher phenol contents across the period of study. Similarly, disease severity increased with increasing inoculum levels with highest attained using 20 ml (23.99%) while higher phenol content was obtained at inoculum level 10 ml (18.61 mg/g) compared to results using 20 ml (15.63 mg/g) and control (7.88 mg/g). The maize variety; ART-98-SW6 with highest stalk rot severity also produced the highest phenol content. Overall, the rate of phenol production in maize corresponded with the extent of severity F. verticillioides infections.

A virus causing mosaic and leaf yellowing symptoms on Mucuna pruriens was isolated and purified through its susceptible host Vigna unguiculata var. TVu 76. Yield of the purified virus obtained was 7.2 mg/kg. It had an ultraviolet (UV) absorption spectrum at 260 nm as 1.53±0.00 and at 280 nm as 1.45±0.00, which translated into nucleic acid content of 72.9 %. Determination of the molecular weight of the virus coat protein from a plotted graph gave 27 kiloDaltons. When the purified virus was electrophoresed in agarose gel, no secondary band was observed. Absorbance curve at 260 nm was obtained when the purified virus was measured spectrophotometrically. A volume of 16 000μL antiserum was obtained against the virus with concentration of 0.3 mg/ml. The titre value determined for the antiserum raised against the virus was 1:2000 as there was a wider difference between the readings obtained for the healthy and diseased controls. At this dilution, the titre value was two and a half times greater than that of the healthy control. The heterologous: homologous percentage (%) obtained for the isolated virus and TMV (Muguga strain) was 50.0 % when Protein-A sandwich enzyme linked immunosorbent assay (PAS ELISA) was used to determine its serological relationship with the virus and other Tobamovirus strains. Keywords: PAS ELISA, Tobamovirus , coat protein, molecular weight

Corchorus olitorus is one of economic important vegetable which plays an extensive role in human diet, herbs and industry as fibre, but the seed borne fungi has constituted a major constraint to the cultivation of this important vegetable especially in the tropics. This study therefore evaluates the pathogenic effect of seed borne fungi of C. olitorus and the use of botanicals as potential biocontrol agents. Out of the three isolated fungi, Macrophomina phaseolina and Collectotrichum corchori were found pathogenic while Fusarium oxysporum showed no significant disease incidence on Corchorus olitorus seedlings. Based on the in-vitro and in-vivo biocontrol experiment, extracts of Moringa oleifera, Pyrus communis and Manihot esculenta, significantly (p<0.05) suppressed the virulence of the seed borne fungal pathogens. The extracts of Pyrus communis at 5% and 10% g/ml concentration levels appeared the most significant (p<0.05) on the seed borne fungi. Thus, the phytofungicidal properties of Pyrus communis extracts can be harnessed for the control of seed borne fungal diseases and improvement of Corchorus olitorus growth.

Screen house experiments were conducted at the Institute of Agricultural Research and Training, Ibadan, on a sandy loam soil in two years, to assess the effect of arbuscular mycorrhizal fungus (Glomus clarum) and compost (sunflower) on the growth and yield of tomato plants. The experimental design was laid out in a Complete Randomized Design (CRD) with nine treatments replicated three times. Arbuscular mycorrhizal fungi (AMF) and Compost (CMP) were applied into 8 kg soil each at the levels of 2.5, 5.0, 7.5 and 10 tonnes/ha each (2.5 g, 5.0 g, 7.5 g and 10 g respectively), while the control had 0 tonnes /ha (0 g). Results showed that plants treated with 5.0 tonnes/ha AMF produced highest cumulative weight of harvested fruits per plant and number of fruits per plant which were significantly higher (P<0.05) than other treatments. Application of 2.5 tonnes/ha CMP significantly (P<0.05) produced the highest number of tomato leaves per plant, while the highest number of flowers per plant was significantly higher for 7.5 tonnes/ha CMP. The tallest plants and plants with highest number of branches were also recorded for 5.0 tonnes/ha AMF. This study showed that 5.0 tonnes/ha is the optimum level of AMF required for the cultivation of tomato plant which could have arisen from optimum uptake of phosphorus in the soil.Keywords: Compost, Glomus clarum, fertility, tomato, yield

The influence of Arbuscular mycorrhiza fungi (AMF) (Glomus deserticola and Gigaspora gigantea) were evaluated on drought tolerance and charcoal rot disease of cowpea genotypes: IT90K-277-2, IT84S-2246-4 and IT06K123-1. IT90K-277-2 and IT84S-2246-4 were sown in 3 kg of sterilized soil for drought experiment with five treatments. Treatment was established thirty days after germination with inoculation of G. deserticola, the mycorrhizal treated cowpea withstand the water stress and produced high yield. Biocontrol experiment had 2 kg sterilized soil potted into bags with cultivars IT90K-277-2 and IT06K123-1, fourteen treatments were established with soil drenched before planting and simultaneous inoculation. Soil drenched with AMF before planting and inoculation of M. phaseolina after 10 days of germination recorded higher growth parameters, while the simultaneous inoculated plant was the most effective in reducing disease severity. However, simultaneous treatment of G. deserticola, G. gigantea and M. phaseolina were most effective for both growth parameters and reduction of disease severity.

Screen house experiments were conducted at the Institute of Agricultural Research and Training, Ibadan, on a sandy loam soil in two years, to assess the effect of arbuscular mycorrhizal fungus ( Glomus clarum ) and compost (sunflower) on the growth and yield of tomato plants. The experimental design was laid out in a Complete Randomized Design (CRD) with nine treatments replicated three times. Arbuscular mycorrhizal fungi (AMF) and Compost (CMP) were applied into 8 kg soil each at the levels of 2.5, 5.0, 7.5 and 10 tonnes/ha each (2.5 g, 5.0 g, 7.5 g and 10 g respectively), while the control had 0 tonnes /ha (0 g). Results showed that plants treated with 5.0 tonnes/ha AMF produced highest cumulative weight of harvested fruits per plant and number of fruits per plant which were significantly higher (Pu003c0.05) than other treatments. Application of 2.5 tonnes/ha CMP significantly (Pu003c0.05) produced the highest number of tomato leaves per plant, while the highest number of flowers per plant was significantly higher for 7.5 tonnes/ha CMP. The tallest plants and plants with highest number of branches were also recorded for 5.0 tonnes/ha AMF. This study showed that 5.0 tonnes/ha is the optimum level of AMF required for the cultivation of tomato plant which could have arisen from optimum uptake of phosphorus in the soil. Keywords : Compost, Glomus clarum, fertility, tomato, yield

ABSTRACT Biocontrol agents isolated outside Africa have performed inconsistently under field conditions in Africa. The development of indigenous phytobeneficial microbial strains that suit local environments may help enhance competitiveness with in situ microorganisms and effectiveness at suppressing local pathogen strains. We isolated bacteria from the rhizosphere of maize growing in southwestern Nigeria and assessed them for growth-promoting characteristics. The best isolates were characterized using 16S rRNA genes and were further evaluated in the greenhouse on maize seedlings. Four isolates (EBS8, IGBR11, EPR2, and ADS14) were outstanding in in vitro assays of antagonistic activity against a local strain of Fusarium verticillioides, phosphate solubilization efficiency, chitinase enzyme activity, and indole-3-acetic acid production. Inoculation of maize seeds with these isolates resulted in ≥95% maize seed germination and significantly enhanced radicle and plumule length. In the greenhouse, maize seedling height, stem girth, number of leaves, leaf area, shoot mass (dry matter), and nutrient contents were significantly enhanced. The bioprotectant and phytobeneficial effects were strongest and most consistent for isolate EBS8, which was identified as a Bacillus strain by 16S rRNA gene analysis. As a bacterial strain that exhibits multiple growth-promoting characteristics and is adapted to local conditions, EBS8 should be considered for the development of indigenous biological fertilizer treatments.

The distribution and aflatoxigenicity of Aspergillus section Flavi isolates in 58 commercial poultry feed samples obtained from 17 states in five agro-ecological zones (AEZs) in Nigeria were determined in order to assess the safety of the feeds with respect to aflatoxin-producing fungi. Correlation was also performed for incidence of species, aflatoxin-producing ability of isolates in vitro, and aflatoxin (AFB1) concentrations in the feed. A total of 1006 Aspergillus section Flavi isolates were obtained from 87.9% of the feed samples and identified as Aspergillus flavus, unnamed taxon SBG, Aspergillus parasiticus and Aspergillus tamarii. A. flavus was the most prevalent (91.8%) of the isolates obtained from the feed in the AEZs while A. parasiticus had the lowest incidence (0.1%) and was isolated only from a layer mash sample collected from the DS zone. About 29% of the Aspergillus isolates produced aflatoxins in maize grains at concentrations up to 440,500μg/kg B and 341,000μg/kgG aflatoxins. The incidence of toxigenic isolates was highest (44.4%) in chick mash and lowest (19.9%) in grower mash. The population of A. flavus in the feed had positive (r=0.50) but non significant (p>0.05) correlations with proportion of toxigenic isolates obtained from the feed while SBG had significant (p<0.001) positive (r=0.99) influence on AFB1 concentrations in the feed. Poultry feed in Nigerian markets are therefore highly contaminated with aflatoxigenic Aspergillus species and consequently, aflatoxins. This is a potential threat to the poultry industry and requires urgent intervention.

This study was carried out to investigate the interaction of maize and Aspergillus niger as influenced by arbuscular mycorrhizal fungi (AMF). Three quality protein maize (QPM) genotypes (ILE1-OB, ART-98-SW5-OB and ART-98-SW6-OB) and two market accessions (Ilishan and Shagamu) were evaluated in a pot experiment conducted under natural environment conditions at the Research and Teaching Farm of Babcock University, Ogun State, Nigeria. AMF (Glomus deserticola) in mixtures of soil and root fragments was inoculated at the rate of 15g per plant, while maize was artificially infected with A. niger (15 cfu ml(-1)) in each designated pots. The coefficient of emergence (COV), percentage emergence (% E) and disease severity were determined using standard methods. Generally, plants treated with AMF only produced the highest cumulative cob yield (18g), followed by plants treated with AMF and A. niger (15g) and then control (12g), while the least was recorded for only A.niger-treated plants (4g).

Carica papaya L. has found importance to mankind as fruit and herb, but the recent outbreak of pawpaw foot-rots, which causes severe attack and huge losses to the C. papaya plantation in Nigeria needs to be investigated. Therefore, this study evaluates the effect of arbuscular mycorrhizal fungi (AMF) on Pythium aphanidermatum, the causative pathogen of pawpaw foot rot. In the open field pot experiment arranged in a complete randomised design, the treatment of P. aphanidermatum alone showed significant (p < 0.05) reductions in the growth parameters of C. papaya seedlings, while the two AMF used in this study; Glomus mosseae and Glomus deserticola significantly (p < 0.05) suppressed the pathogenic effects of P. aphanidermatum and also enhanced the seedling growth when applied alone. However, G. deserticola recorded higher significance (p < 0.05) effect in this study. Apart from the biocontrol activities of the two AMF on P. aphanidermatum, they are also excellent bio fertilisers that significantly (p < 0.05) enhance the growth of C. papaya seedlings. Thus, the unique potentials of AMF especially G. deserticola should be harnessed in crop production.

This study investigates the phytofungicidal potentials of aqueous extracts of Mangifera indica and Jatropha curcas on the Fusarium pathogens of millet seedlings in southwestern Nigeria. Aqueous extracts of M. indica and J. curcas prepared at 0.15, 0.30 and 0.45 mg/ml concentration levels were evaluated in-vitro using standard methods, while the in-vivo experiment was carried out using soil inoculation method in a completely randomized design with three replications. Data on percentage mycelia inhibition, growth characters, disease incidence and severity were obtained, and statistically analyzed using SAS 9.1 statistical software. Based on the in-vitro experiment, J. curcas significantly (p<0.05) inhibited the mycelial growth of Fusarium pathogens at increasing concentrations better than M. indica. The in-vivo result showed that J. curcas at 0.15, 0.30 and 0.45 mg/ml concentrations significantly (p<0.05) suppressed F. anthophilum, F. verticillioides and F. oxysporum. Similarly, M. indica at 0.30 and 0.45 mg/ml concentrations was observed to show significant (p<0.05) effect on F. verticillioides and F. scirpi. However, both extracts significantly (p<0.05) reduced the incidence and severity of disease caused by F. anthophilum and F. oxysporum at concentration levels tested in comparison to the controls. The inhibitory effects of the extracts were negative and insignificantly (p<0.05) correlated with days of observation in vitro and with the growth characters in vivo. Fusarium spp showed negative and significant (p<0.05) association with disease severity while positive and significant (p<0.05) relationship existed between the extracts and disease severity. Therefore, the botanicals of J. curcas and M. indica were considered effective against Fusarium pathogens of millet seedlings. Hence, they could be employed in large scale farming for sustainable millet production in Nigeria.

The efficacy of some botanicals and bio-agents were assessed in vitro as the potential biofungicides against Fusarium verticillioides, the causal organism of stalk rot disease of maize plant. The botanicals used in this study were Morinda lucida (Oruwo) and Tithonia diversifolia (Mexican Sunflower) and the bio-agents used were Trichoderma viride, Trichoderma harzianum, Trichoderma pseudokoningii and Bacillius subtilis. All the plant extracts and antagonistic organisms significantly inhibited the growth of Fusarium verticillioides. However, out of the antagonists, T. viride provided the highest inhibitory effect followed by T. pseudokoningii, T. harzianum, and B. subtilis which was the lowest suppressive antagonist. The extract from T. diversifolia, provided the highest inhibitory effect followed by M. lucida. Key words: Maize, ear rot, botanicals, bioagents, Fusarium verticillioides.