Allelopathy Effect of Trichoderma spp. and Some Plant Extracts against Pythium aphanidermatum (In-vitro)

The antibacterial activity of the n-hexane, acetone/dichloromethane, ethanol and aqueous extracts of twelve common medicinal plants from the Philippines obtained through pounding and solvent extraction was evaluated using disc Agar diffusion. The microorganisms tested were: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Susceptibility test results showed that different extracts (1000 mcg/disc) from ten plants inhibited growth with a mean zone of inhibition range of 15 to 30 mm against S. aureus, E. coii, and P. aeruginosa. The common medicinal plants which showed highly positive activity were Psidium guajava (guava), Eucalyptus globulus, Mangifera indica(Indian mango), Nasturtium officinale (Watercress), Pterygospermum oleiferum (Moringa),Carmona retusa (Wild tea), Citrus aurantifolia (Lemon), Citrus sinensis (Orange), Allium sativum (garlic), and Allium cepa (onion). Preliminary phytochemical screening revealed the presence of flavonoids, tannins, alkaloids, glucosides, saponins and steroids/terpenes. The results suggest that the different plant extracts contain bioactive constituent(s) particularly tannins, flavonoids, terpenoids and other glycosides with very strong antibacterial activity and validates the ethno-medical use in the treatment of bacterial skin diseases and other forms of bacterial infections. However, many reputed plant antibacterials have very variable activities depending on certain conditions. Key words: Antibacterial, medicinal plants from the Philippines, n-hexane, acetone/dichloromethane, ethanol, aqueous extracts, Psidium guajava, preliminary phytochemical screening.

Incidence of root rot and damping-off caused by Fusarium solani and Sclerotium rolfsii on cowpea plants was successfully controlled by some plant extracts, essential oils, bioagents, systemic resistance-chemical inducers and seed dressing fungicides which tested under laboratory, greenhouse and field conditions in two successive seasons (2008 and 2009). All tested plant extracts; Artemisia absinthium, Ocimum basilicum and Mentha longifolia; significantly reduced the linear growth of F. solani and S. rolfsii. The maximum inhibition in fungal radial growth was induced by Ocimum basilicum and Artemisia absinthium with averages of 81.29 and 61.99%, respectively. All the tested essential oils reduced the fungal growth of S. rolfsii, the most effective oils were Syzygium aromaticum and Eucalyptus globulus with averages of 87.70 and 81.10 %, respectively. On the other hand, using culture filtrates of Trichoderma harzianum, T. viride and Bacillus subtilis significantly reduced the linear growth of F. solani and S. rolfsii with the average of 75.28, 69.62, and 54.36%, respectively. Results of chemical inducers revealed that salicylic acid have the highest inhibition effect on the mycelial growth of F. solani and S. rolfsii with the average of 20.00 and 29.63 %, respectively. Under greenhouse conditions, all treatments caused significant decrease of disease incidence and increase of survival plants, as compared to the untreated plants. Soaking seeds in Ocimum basilicum extract and S. aromaticum oil decreased damping-off and had the highest percentage of healthy survival cowpea plants. Soaking cowpea seeds in Vitavax-captan or in the suspension of T. harzianum, (however, had the best effect) for decreasing damping-off and increasing survival plants. The disease could be controlled also by salicylic acid and ascorbic acid (4mM) which decreased damping-off and root-rot incidence and increased survival plants. On the other hand, there is a correlation between induced resistance and some biochemical changes in leaf tissues of cowpea healthy plants such as increasing the activity of peroxidase and Polyphenol oxidase enzymes. T. harzianum, salicylic acid and S. aromaticum produced the highest level of peroxidase and Polyphenol oxidase enzymes activity. Under field conditions, Vitavax-captan, bioagents T. harzianum, plant extract; Ocimum basilicum, essential oil; S. aromaticum and resistance-inducing chemical salicylic acid significantly reduced disease incidence and increased seed yield production.

Background: Plant materials are repositories of bioactive compounds with medicinal value, often utilized in traditional medicines for their therapeutic potential. This study aimed to evaluate the antimicrobial efficacy of extracts from Syzygium aromaticum, Thymus vulgaris, and Eucalyptus globulus against Salmonella typhi, Staphylococcus aureus, Escherichia coli, and Candida albicans. Methods: Plant extracts were obtained using soxhlet extraction with ethanol as the solvent. The extracts were qualitatively screened for the presence of alkaloids, saponins, flavonoids, and tannins. The residual concentrations of the plant extracts were determined to be 2.0 mg/mL for Syzygium aromaticum, 2.1 mg/mL for Thymus vulgaris, and 1.83 mg/mL for Eucalyptus globulus. The antimicrobial activity was assessed, and the minimum inhibitory concentration (MIC) for each extract against the tested microorganisms was determined. Results: All plant extracts contained saponins and flavonoids, while only extracts from Eucalyptus globulus, Thymus vulgaris, and Syzygium aromaticum contained tannins. Alkaloids were not present in the extracts. Staphylococcus aureus was susceptible only to Syzygium aromaticum extract. Salmonella typhi showed no sensitivity to any of the extracts. Escherichia coli was sensitive to all extracts, with the order of efficacy being Eucalyptus globulus > Thymus vulgaris > Syzygium aromaticum. Candida albicans was sensitive to Syzygium aromaticum and Thymus vulgaris extracts. The MIC for Syzygium aromaticum was 2.0 mg/mL for S. aureus, E. coli, and C. albicans. Thymus vulgaris exhibited MIC values of 0.021 mg/mL and 2.1 mg/mL for E. coli and C. albicans, respectively. Eucalyptus globulus had a MIC of 1.83 mg/mL for E. coli. Conclusion: The plant extracts from Syzygium aromaticum, Thymus vulgaris, and Eucalyptus globulus demonstrated antimicrobial activity against S. aureus, E. coli, and C. albicans. These findings suggest that these plant materials may be useful as natural remedies for managing infections caused by these susceptible microorganisms. Further research is warranted to explore their potential applications in clinical settings.

Field experiments were carried out at the National Horticultural Research Institute, Okigwe, Imo State during the late cropping of 2012 and was repeated at the same cropping season in 2013 to evaluate the efficacies of some ethanol plant leaf extracts namely: garlic ( Allium sativum ), Neem ( Azadiracta indica), Ocimum gratissimum, Moringa olifera and tithonia on the insect pests of cucumber. The treatments consisted of three levels of concentration of each of the five extracts namely 50%, 75% and 100% as well as distilled water, concentrated water and synthetic insecticide cypermetrine at12.5% E.C. There were eighteen treatments for each season which were replicated three times in a split-plot experimented design. Results of the studies showed the identified commonest insect pest of the crop in the 2012 and 2013 cropping seasons to include flea beetles ( Cerotoma ruficornis ), cucumber beetle, Leptoglossus autralis and Diabrotica spp . The results also demonstrated that all the tested plant extracts at bi-weekly spraying interval were efficacious in controlling the insect pests. The efficacy of Allium sativum at 100% concentration was highest of all the plant extracts where 0.84kg/plot and1.05kg/plot were recorded in 2012 and 2013 seasons respectively. This was followed by 100% concentration of Azadirachta indica , 100% ocimum , 100% Moringa olifera and tithonia in that order. The efficacy of the cypermethrine (synthetic insecticidial check) was highest having performed best. Significant difference (P < 0.05) existed between the untreated (control) and all the treated plots in insect population and yield. However, the tested plant extracts at the three different concentration of 50%, 75% and 100% in both seasons proved efficacious in the control of the insect pests of cucumber as78.2% reduction in insect population, 79/8% reduction in leaf damage and 79.3% marketable fruit number were recorded in 2012 and 82.7% reduction in insect population, 76.4% reduction in leaf damage and 85.9% marketable fruit number in 2013 cropping season.

Four aqueous traditional plant extracts from rosemary leaves (Rosmarinus officinalis), clove buds (Syzygium aromaticum [L.] Merr at Perry, Myrtaceae), cinnamon bark (Cinnamomum zeylanicum) and ginger rhizomes (Zingiber officinale) were tested as natural antibiotics against multi-drug resistant bacteremia isolates: Six Gram negative isolates, viz. Acinetobacter baumanni/haemolyticus, Citrobacter freundii, Escherichia coli, E. coli ESβL, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella sp. and four Gram positive isolates viz. methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Streptococcus pneumoniae and Bacillus sp. were which used to test antibiotic activity. The usage of clove extract (25X) appeared to have maximum antibacterial activity against all tested Gram negative bacteria, when compared with other tested plant extracts at the same concentration. In the case of G+ve bacteria, tested extracts appeared to have almost the same efficiency. Swabs were taken from inhibition zone resulting from the inhibitory effect of aqueous extracts towards the tested isolates and re-inoculated to detect either the bacteriostatic or bactericidal action. Again, clove extract exhibited the highest effect when compared with other tested against the isolates from bloodstream. Scanning electron microscopy was used to record external morphological changes of the bacterial cells such as appendages, shortness and lyses. Key words: Aqueous plants extracts, bacteremia, antibiotics, rosemary, clove, cinnamon, ginger, Escherichia coli, Salmonella, Acinetobacter, Citrobacter, Klebsiella, Pseudomonas, Streptococcus, Bacillus, Staphylococcus.

Field experiments were carried out at the National Horticultural Research Institute, Mbato Okigwe Out-station, Imo State during the early cropping seasons of 2015 and 2016 to evaluate the efficacy of some ethanol plant leaf extracts of Garlic (Allium sativum) and Neem (Azadirachta indica ) on the insect pests of Telfairia occidentalis. Three levels of concentration of each of the two extracts viz: 50%, 75% and 100% were used. There were eight treatments for each season which were replicated three times in a splt-plot experimental) design. Cypermethrine (12.5% E.C) served as insecticidal check. Result of the studies in 2015 and 2016 cropping seasons showed the identified insect pests of the crop to include Leaf beetle (Podagrica spp), Zonocerus variegatus Aulucephora spp and Fruit flies (Dacus spp.). The result also showed that the three levels of concentration of the active ingredients oleoresin oil and azadirachtin of the tested plant extracts at bi-weekly spraying interval were efficacious in controlling the insect pests. The identified insect pests though constituted a nuisance to the Telfairia leaves by feeding on them but the damage caused was very low or minimal on the plants treated with the active ingredients of the extracts compared with the untreated in both cropping seasons. Also plants treated with100% and 75% concentrations of the active ingredients of A. sativum and A. indica significantly gave more yield in terms of leaf, vine number, pod number and pod weight than other levels of concentration of both plant extracts used in the trial. The efficacy of the cypermethrine was highest for all the parameters considered. The study also revealed that the extracts at higher concentrations of 75% of the active ingredients and above are efficacious and could serve as an alternative in the control of insect pest of Telfairia occidentalis.

Eight plant extracts, bio agents and fungicides were evaluated in in vitro conditions against purple blotch and Stemphylium blight of onion caused by Alternaria porri and Stemphylium vesicarium. Among the plant extracts, clove extracts of Allium sativum at 10% resulted in maximum inhibition of growth (58.05 and 57.31%) of A. porri and S. vesicarium,respectively followed by Aloe vera at 10% (53.5 and 47.15%). Among the bioagents,Trichoderma viride was effective in inhibition of growth (53.17 and 56.15%). Out of eight fungicides evaluated, Mancozeb at 0.2% completely inhibited the growth of both the pathogens. Azoxystrobin (0.1%), propiconazole (0.1%) and antracal (0.2%) were the other effective fungicides. Key words: Onion, Allium cepa, Alternaria porri, Stemphylium vesicarium, management.

The results revealed that all the six bioagents tested in vitro applying dual culture technique against Phytophthora nicotianae , Phytophthora citrophthora and Phytophthora palmivora significantly inhibited the mycelial growth of the test pathogen over untreated control. However, bioagent, Trichoderma harzianum recorded minimum mean colony diameter (7.73 cm 2 ) and highest inhibition (87.85%) of mycelial growth of P. nicotianae over untreated control followed by the bioagent T. viride , T. koningii which recorded mean colony diameter of 9.95 cm 2 , 14.15 cm 2 and mean mycelial inhibition of 84.36 %, 77.76%, respectively. Evaluation of different botanicals by Poisoned Food Technique showed that all plant extracts tested in vitro were found significantly effective in reducing the percentage mycelial growth of P. nicotianae , P. citrophthora and P. palmivora over untreated control. However, plant extract (@ 5, 10 and 15%) of Garlic, recorded lowest mean colony diameter (47.45 mm) and highest mean mycelial growth inhibition (47.26%) followed by Neem, Onion which recorded the mycelial growth of 55.20 mm, 60.85 mm, and the mean mycelial growth inhibition of 38.65%, 32.38%, respectively. Results revealed that all the nine fungicides tested in vitro applying Poisoned Food Technique against P. nicotianae , P. citrophthora and P. palmivora significantly inhibited the mycelial growth of the test pathogen over untreated control. However, fungicide, Cymoxynil 8% + Mancozeb 64% (Curzate M-8) recorded minimum mean colony diameter (16.12 mm) and maximum mean inhibition (82.09%) of mycelial growth of the test pathogen over untreated control (mean colony diameter 90.00 mm and mean inhibition 0.00) followed by the fungicide Metalaxyl-M 4% + Mancozeb 64% (Ridomil Gold), Metyram (Polyram) , which recorded mean colony diameter of 20.16 mm, 24.16 mm and mean mycelial inhibition of 77.59%, 73.14%, respectively.

Pythium aphanidermatum is one of the most important agent of root and foot rot of cucumber, particularly in the warm humid climate. Induction of host resistance by microorganisms or by the synthetic compounds is recently considered as one of the biological control method of disease. Trichoderma harzianum Bi is a good candidate for induction of resistance in plant against diseases. The maximum level of resistance of seedlings to P. aphanidermatum after inoculation with T. harzianum Bi was determined using completely randomized design in greenhouse condition. The results based on the fresh root weight and root rot index of seedlings showed that the maximum level of resistance against P. aphanidermatum is induced 7 days after treatment of cucumber seedlings by T. harzianum. The variation of peroxidase activity, its isozymes, and the total soluble proteins in root extract induced by T. harzianum Bi in cucumber seedlings was determined by colorimetric and native Electrophoresis methods before and after inoculation the seedlings by P.aphanidermatum. The results showed that the maximum level of resistance induction in seedlings treated by T. harzianum Bi coincide with maximum activity of peroxidase. The peroxidase activity was evaluated by Guaiacol oxidation rate in the presence of H2O2 and changing of solution color to orange reddish, measured by the variation of light absorption per min/ mg soluble protein of root extract. The same experiment realized on T. harzianum Bi, P. aphanidermatum and the combination of two fungi demonstrated that both fungi can influence individually the peroxidase activity, but it is more pronounced and more stable and persistent in the case of seedling inoculation by combination of two fungi in comparison to the control. Keywords: Pythium aphanidermatum, Trichoderma harzianum Bi, Root and crown rot, Biological control, Induced resistance, Peroxidase

주엽, 차나무, 계피, 란타나 등의 추출물과 이들의 혼합물들에 대한 차응애의 포식성 천적인 긴털이리응애의 감수성을 검정하였다. 긴털이리응애 암컷 성충은 실험 식물추출물들의 처리 7일 후에 72∼94%의 생존율을 나타냈으며, 무처리 암컷 성충에 비해 68.1∼94.5%의 산란수를 보였고 산란된 난들의 부화에 영향이 없었다. 실험 식물추출물들의 처리는 긴털이리응애 난의 부화에 대해 별 영향이 없었다. 또한 이들 식물추출물의 처리는 약충의 생존율에도 큰 영향이 없었다. 이상의 결과로 보아, 실험 식물추출물들은 차응애의 종합관리 체계에서 긴털이리응애와 함께 활용할 수 있을 것으로 생각된다.The susceptibility of Neoseiulus womersleyi, a native predaor of Tetranychus kanzawai, to extracts of Gleditsia japonica var. koraiensis, Camellia sinensis, Cinnamomum cassia, Lantana camara and their mixtures was evaluated. In the treatments with the tested plant extracts, 72∼94% of adult female predators survived after 7 days of treatment. Adult female predators treated with the tested plant extracts produced 68.1∼94.5% as many eggs as did the control females, and the hatching of eggs deposited by the treated predators was not affected. Moreover, the treatments of the plant extracts tested showed no significant effect on the hatch of N. womersleyi eggs. The survival of N. womersleyi nymphs was not seriously affected by being exposed to the tested plant extracts. These results suggest that the extracts of Gleditsia japonica var. koraiensis, Camellia sinensis, Cinnamomum cassia, Lantana camara, and their mixtures expected to be promising candidates for the use in the integrated mite management program with N. womersleyi.

Herbal remedies are crucial for treating bacterial infections due to antibiotic resistance, with numerous studies demonstrating their antibacterial properties against various harmful species. This study investigates the antibacterial properties of an aqueous extract from 40 medicinal plants in vitro, assessing their effectiveness against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The well diffusion method was employed to assess the antibacterial activity. Six plants exhibit antibacterial properties against the two bacterial strains among these extracts. Guava (Psidium guajava) and Clove (Syzygium aromaticum)cold water extracts were the most effective plant extracts against Escherichia coli, with inhibition zones of 6.2 mm and 5.2 mm, respectively. Coriander (Coriandrum sativum) leaves and Sana makki (Cassia angustifolia) leaves cold water extracts were the most effective plant extracts against Staphylococcus aureus with an inhibitory effect with inhibition zones of 6.9 mm and 5.9 mm respectively. The plant extracts differ in antibacterial activities against S. aureus and E. coli. However, Extracts of Senna alata, Tamarindus indica, Psidium guajava, Syzygium aromaticum, and Cassia angustifolia showed inhibitory activity against both of the microorganisms tested. These potentially useful plant extracts can be utilized as natural alternatives to preventive measures for food poisoning and preservation, thereby avoiding the health risks associated with chemically antibacterial agents. These antibacterial properties encourage future research into new chemical compositions that can help treat or cure some diseases.

A study was conducted in the of Department Plant Pathology, Marathwada Agricultural University, Parbhani, Maharashtra during 2009 to 2010 to control Colltotrichum truncatum causing anthracnose / pod blight of soybean with plant extracts and bio-agents . All the nine aqueous leaf extracts and four species of antagonist Trichoderma evaluated in vitro were found effective against C. truncatum and recorded significant inhibition of the test pathogen over untreated control. However, T. viride was found most effective and recorded 18.53 mm mean colony diameter and recorded significantly highest growth inhibition (79.40 %) of the test pathogen. This was followed by T. hamatum and Pseudomonas fluorescens with 73.74 and 69.31 per cent growth inhibition, respectively. Of the aqueous leaf extracts evaluated, Garlic recorded significantly highest growth inhibition (81.82%) of the test pathogen. The second and third best plant extracts found were Tulsi (65.17 % inhibition) and Onion (60.31% inhibition) both of which were on par. Among the nine fungicides, Carbendazim recorded least mean colony diameter (7.52 mm) and highest inhibition (91.63 %) of mycelial growth of the test pathogen over untreated control, followed by Mancozeb which recorded mean colony diameter of 10.38 mm and mean mycelial growth inhibition of 88.45 per cent. In field, Carbandazim (@ 0.1%) recorded least mean disease intensity (19.55%), mean pod infection (9.63%), highest seed yield (2605 kg/ha) and test weight (14.33 g). It also recorded highest reductions in the disease intensity (40.73%), pod infection (75.73%) over unsprayed control followed by Mancozeb (@ 0.1%) which recorded the minimum mean disease intensity (21.50%) pod infection (10.78%). Considering incremental cost: benefit ratio (ICBR), the most economical treatment which recorded highest cost: benefit ratio was the fungicide Carbendazim (C:B ratio, 1:14.45) followed by Carbendazium + Mancozeb (C:B ratio, 1:8.92).

The indiscriminate use of chemical fungicides led to pesticide residues in food products, risk of development of new pathotypes and pollution of soil and water ecosystem. This resulted in several ill effects on human beings, flora and fauna. To overcome the ill effects of chemical pesticides, attention had been paid to explore into products of higher plants for developing novel biopesticides in plant disease management. Our ancestors had been using these botanicals for the management of plant diseases, before the era of conventional fungicides. But the popularity of pesticides of plant origin has again been increasing due to its potential fungicidal action against several plant pathogens without any deleterious effect to the crop plants as well as environment. Several plants have been identified for antimicrobial properties which can suppress the growth and multiplication of plant pathogens, reduction in storage decay and spoilage of food products. The potential plant origin pesticides, viz. neem (Azadirachta indica), garlic bulb (Allium sativum), eucalyptus (Eucalyptus globulus), turmeric (Curcuma longa), tobacco (Nicotiana tabacum), ginger (Zingiber officinale), etc., have been successfully used for the management of several plant diseases. Moreover, seed treatment + foliar spray of freshly prepared garlic bulb extract has resulted into the reduction of Alternaria blight (35.6 %), white rust (50.4 %), powdery mildew (67.7 %) and Sclerotinia rot (80.3 %) in mustard with 27.3 % increase in yield over untreated control. These pesticides can suitably fit in any integrated pest management framework as well as in organic farming system which is a necessity in the current situation. Keeping in view the ever-increasing demand for safe food, pesticides of plant origin have a pivotal role to play in the management of plant diseases in comparison to the conventional chemical pesticides. These pesticides are not only useful to the developing countries due to their easy availability, being relatively cheap, easy sustenance in any crop protection programme and having direct relevance to the developed countries for healthy and quality produce of foodstuffs.

In this study, we investigated the feasibility of using Psidium guajava, Mangifera indica and Ocimum gratissimum leaf extracts in preventing Escherichia coli biofilm formation. The plants extractions were done with methanol under cold extraction. The various concentrations 5.0, 10.0 and 20.0 mg mL(-1) were used to coat 63 catheters under mild heat from water bath. Biofilm formation on the catheter was induced using cultures of E. coli. Biofilm formation was evaluated using aerobic plate count and turbidity at 600 nm. From the obtained results, Psidium guajava, Mangifera indica and Ocimum gratissimum delayed the onset of biofilm formation for a week. Ocimum gratissimum coated catheter had the highest inhibitory effect at 5.0, 10.0 and 20.0 mg mL(-1) with bacterial count ranging from 2.2 x 10(5)-7.0 x 10(4) and 5.7 x 10(5)-3.7 x10(5) for 120 and 128 h, respectively. The Psidium guajava coated catheter had the lowest inhibitory effect at 5.0, 10.0 and 20.0 mg mL(-1), with bacterial count ranging between 4.3 x 10(5)-1.9 x 10(3) and 7.7 x 10(5)-3.8 x 10(5) for 120 and 128 h, respectively. Despite the antimicrobial activities, the differences in the activity of these plant extracts were statistically not significant (p < 0.05).

The objectives of the experiment were to evaluate effectiveness of seed treatments to eliminate Cmm of infected tomato seed lot, evaluate physiological quality of Cmm infected tomato seed lot after treatments with plant extracts. The research used curcuma rhizomes, betel vine leaf extract, cinnamon and clove oil to eliminate Cmm in tomato seed. Part of the seeds were dipped in either suspension of curcuma rhizomes, betel vine leaf extract, cinnamon and clove oil for 20 minutes and the others were matriconditioned using a mixture of burned rice hull (at 22 0C and RH 60-70%) plus either of plant extracts or oils. Elimination of Cmm from infected seeds was observed 10 days after treatments, and physiological seed qualities were evaluated before and after seed treatments. Results of the experiment indicated, dipping infected seeds in either 5% of curcuma, betel vine extract, cinnamon oil or 0.5% of clove oil suspension or matriconditioning plus either these extracts, eliminated 99% of infected Cmm on tomato seeds. Seed treatments using plant extracts for elimination of Cmm did not reduce seed germination, germination rate, vigor index, and did not increase time to reach 50% total germination (T50) of infected tomato seed except the seed treatment by using 5% cinnamon oil with or without matriconditioning. Key words: plant extracts, physiological quality, seed viability, vigor