Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe
crenata were screened for their antimicrobial activities. Solvents
used included water, methanol, and local solvents such as palmwine,
local gin (Seaman's Schnapps 40% alcoholic drink,) and "omi ekan-ogi"
(Sour water from 3 days fermented milled maize). Leaves were dried and
powdered before being soaked in solvents for 3 days. Another
traditional method of extraction by squeezing raw juice from the leaves
was also employed. All extracts were lyophilized. These extracts were
tested against some Gram-negative organisms ( Escherichia coli	 ATCC
25922, Escherichia coli, Pseudomonas aeruginosa , Klebsiella
pneumoniae , Shigella flexneri , Salmonella paratyphi , Citrobacter
spp); Gram-positive organisms Staphylococcus aureus ATCC 25213,
Staphylococcus aureus, Enterococcus faecalis , Bacillus subtilis )
and a fungus ( Candida albicans ). Agar well diffusion and broth
dilution methods were used to determine the minimum inhibitory
concentration (MIC) and minimum bactericidal concentration (MBC) at
concentrations of 512mg/ml to 4mg/ml. All the organisms except Candida
albicans were susceptible to the extracts obtained from the traditional
method. The squeezed-leaf juice of Kalanchoe crenata was the most
active one with MIC of 8 mg/ml against Pseudomonas aeruginosa,
Klebsiella pneumoniae and Bacillus subtilis, 32 mg/ml against Shigella
flexneri, 64 mg/ml against Escherichia coli and 128 mg/ml against the
control strain Staphylococcus aureus while its MBC is 256 mg/ml against
these organisms except Bacillus subtilis and Klebsiella pneumoniae. The
Gram-positive organisms were more sensitive to the methanol and local
gin-extract of Bryophyllum pinnatum. Extracts from other solvents
showed moderate to weak activity.

/pdf/in-vitro-antimicrobial-activity-of-crude-extracts-from-2nk3s03gpy.pdf

In Vitro Antimicrobial Activity Of Crude Extracts From PlantsBryophyllum Pinnatum And Kalanchoe Crenata

Thirty-four endophytic fungal isolates were obtained from the leaves of the medicinal plant Polyscias fruticosa, and their antagonistic activities against the growth of the common tomatoes plant pathogenic fungus Athelia rolfsii were initially screened using a dual culture assay. The endophytic fungus MFLUCC 17-0313, which was later molecularly identified as Diatrype palmicola, displayed the highest inhibition percentage (49.98%) in comparison to the others. This fungus was then chosen for further evaluation. Its culture broth and mycelia from a 10 L scale were separated and extracted using ethyl acetate, methanol, and hexane. Each extract was tested for antifungal activity against the same pathogen using a disc diffusion assay. Only the crude hexane extract of fungal mycelium showed antifungal activity. The hexane extract was fractioned using sephadex gel filtration chromatography and each fraction was tested for antifungal activity until the one with the highest inhibition percentage was obtained. The bioactive compound was identified as 8-methoxynaphthalen-1-ol using nuclear magnetic resonance spectroscopy and mass spectrometry. The minimum inhibition concentration of 8-methoxynaphthalen-1-ol was demonstrated at 250 µg/mL against the selected pathogen. Using the leaf assay, the solution of 8-methoxynapthalen-1-ol was tested for phytotoxic activity against A. rolfsii and was found to have no phytotoxic effects. These results showed that 8-methoxynaphthalen-1-ol has the potential for controlling the growth of A. rolfsii, the cause of Southern blight disease on tomatoes. This study may provide the foundation for future use of this compound as a biofungicide.

Antifungal activity of 8-methoxynaphthalen-1-ol isolated from the endophytic fungus Diatrype palmicola MFLUCC 17-0313 against the plant pathogenic fungus Athelia rolfsii on tomatoes

Aqueous extracts of three aromatic and medicinal plants, viz. lemongrass (Cymbopogon citratus), laurel (Laurus nobilis) and cotton-lavender (Santolina chamaecyparissus) were tested against the growth of Fusarium oxysporum f. sp. lentis. The aqueous extracts concentrations were evaluated from 0.05 to 20 mg/mL. Ultra-High-Performance Liquid Chromatography (UHPLC)-Quadrupole-Time-of-Flight-Mass Spectrometer and UHPLC-potato dextrose agar were used to identify and quantify the major phenolic compounds. Lemongrass extract revealed the best antifungal activity; a concentration of 0.05 mg/mL inhibited 67% of conidial germination and 77% sporulation, 5 mg/mL restrain 70% of mycelial growth and 20 mg/mL stopped almost completely the pathogen. The extracts of laurel and cotton-lavender exhibited a moderate inhibition on conidial germination and mycelial growth even at 20 mg/mL, while laurel extracts inhibited 75% of sporulation at 0.05 mg/mL. Four phenolic acids and 16 flavonoids were identified and quantified in the three aqueous extracts. Luteolin derivatives represent 96% of the phenolic compounds identified in lemongrass while procyanidin and caffeic acid derivatives represent 76% and 96% in laurel and cotton-lavender, respectively. Our investigation demonstrates that lemongrass was an actual source of aqueous extract with a biomolecule content that could effectively be used for the control of lentil Fusarium wilt.

Composition and antifungal effects of aqueous extracts of Cymbopogon citratus, Laurus nobilis and Santolina chamaecyparissus on the growth of Fusarium oxysporum f. sp. lentis

African Plant Biodiversity in Pest Management

Tomato late blight is an economic disease that causes 100 % yield loss of tomato in Cameroon. The objective of the study was to determine the efficacy of mancozeb and Ocimum gratissimum extract in managing late blight disease in Nadira and Rio-grande tomato varieties. Seedlings of each tomato variety were planted in replicates of three in a complete randomized block design comprising of three treatments (T1 –Ocimum gratissimum extract (1666.7 g/15 L); T2 –Mancozeb (50 g/15 L); T3 –control. Fifty grams of mancozeb (50g) and 1666.7 g of O. gratissimum extract dissolved and mixed with water in a 15 L knapsack sprayer was applied to control tomato late blight from the onset of blight symptoms, at two days intervals, to control Data for the disease incidence, severity, and yield parameters were collected at weekly intervals for four weeks from plants in the middle of the ridges. Mancozeb and O. gratissimum extract significantly reduced the disease Original Research Article Bi et al.; JABB, 23(10): 45-53, 2020; Article no.JABB.65085 46 severity of Nadira and Rio-grande tomato varieties by 0.2., resulting in a mean fruit number of 18.31 and 16.31 fruits and fruit weight of 1.44 g and 1.13 g. There was no significant difference (p =0.05) between plants sprayed with Mancozeb and O. gratissimum extract. The Nadira variety was resistant to the tomato late blight caused by Phytophthora infestans. Thus biopesticides (O. gratissimum) can be effectively used as alternatives to synthetic fungicides (mancozeb) –which pose risks to human and environmental health.

/pdf/efficacy-of-mancozeb-and-ocimum-gratissimum-extract-in-the-2yb146za4y.pdf

Efficacy of Mancozeb and Ocimum gratissimum Extract in the Management of Late Blight Disease in Tomato Varieties

Tomato (Lycopersicon esculentum Mill.) is a popular fruit vegetable in Nigeria but production is low due to diseases, among the various disease problems associated with tomato production is southern blight caused by Sclerotium rolfsii. This study was carried out to evaluate the efficacy of Aframomum melegueta, Ocimum gratissimum and Cymbopogon citratus in vitro and in vivo. Infected tomato stems were obtained from the experimental plots of National Horticultural Research Institute, Nigeria. Cultural and morphological identification of the organism was done with the use of microscope. A. melegueta seeds, fresh leaves of O. gratissimum and C. citratus were used. The experiment was replicated three times, radial growth (mm) was measured for 5 days at an interval of 24 h. The in vivo experiment was conducted using the same extracts in a screen house and the experiment was laid out in triplicates in completely randomised design with the synthetic fungicide as control. Data collected were subjected to analysis ...

Sclerotium rolfsii management in tomato using Aframomum melegueta, Ocimum gratissimum and Cymbopogon citratus

Sclerotium rolfsii Sacc. is an important fungal pathogen affecting the production of tomato (Lycopersicon esculentum Mill.). Conventional control methods using chemicals are expensive, which constitute environmental hazards. This has necessitated the search for alternatives in botanicals. Ethanol and supernatant solution of fermented maize slurry extracts from Ocimum gratissimum, Cymbopogon citratus, Xylopia aethiopica, Aframomum melegueta and Allium sativum were evaluated. In vitro test was carried out at 1, 2, 3, 4 and 5% concentrations against the pathogen. Mycelial growth was significantly reduced in the following descending order: O. gratissimum > A. melegueta > A. sativum > X. aethiopica > C. citratus. Supernatant solution extracts of O. gratissimum and A. melegueta at 5% concentration gave highest mycelial reduction (0.00 mm), respectively, while O. gratissimum ethanol extract recorded highest mycelial reduction (0.23 mm) among the ethanol extracts. Supernatant solution of fermented maize slurry ex...

In vitro effect of fermented maize slurry and ethanol extracts of five plants against Sclerotium rolfsii Sacc. of tomato (Lycopersicon esculentum Mill.)

E.A. Adesegun

Papers

Sclerotium rolfsii management in tomato using Aframomum melegueta, Ocimum gratissimum and Cymbopogon citratus

In vitro effect of fermented maize slurry and ethanol extracts of five plants against Sclerotium rolfsii Sacc. of tomato (Lycopersicon esculentum Mill.)