Efficacy of Leaf Oil from Pimenta racemosa var. racemosa in Controlling Bacterial Wilt of Tomato

Bacterial wilt, caused by Ralstonia solanacearum, is a major plant disease throughout the Caribbean. The ability of the essential oil from Pimenta racemosa var. racemosa to control bacterial wilt of tomato (R. solanacearum, phylotype IIB/4NPB) was investigated. Lemongrass (chemotype 1)-, aniseed (chemotype 2)-, and clove (chemotype 3)-scented chemotypes of P. racemosa var. racemosa essential oil were tested. Six concentrations of emulsified essential oil (from 0.01 to 0.14% [v/v]) were evaluated by in vitro culture amendment assays and by in vivo experiments in greenhouse. Chemotype 3 displayed remarkable in vitro antibacterial activity against R. solanacearum, because the minimum inhibitory concentration was only 0.03%, compared with 0.14% for chemotypes 1 and 2. In greenhouse experiments, no incidence of bacterial wilt was observed in tomato plants grown in soil treated with chemotype 3 of P. racemosa var. racemosa at a concentration of 0.14%. In the untreated control soil, 62% of plants displayed symptoms of bacterial wilt. Treatment with chemotype 3 significantly increased the growth of tomato plants compared with untreated controls. These results suggest that chemotype 3 of P. racemosa var. racemosa essential oil is a good candidate for further development as a soil biofumigant for the control of tomato bacterial wilt.

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Assessment of Mint, Basil, and Lavender Essential Oil Vapor-Phase in Antifungal Protection and Lemon Fruit Quality

Molecules ◽

10.3390/molecules25081831 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1831 ◽

Cited By ~ 1

Author(s):

Renata M. Sumalan ◽

Raufdzhon Kuganov ◽

Diana Obistioiu ◽

Iuliana Popescu ◽

Isidora Radulov ◽

...

Keyword(s):

Essential Oil ◽

Postharvest Quality ◽

Quality Properties ◽

Chemical Treatments ◽

In Vivo Experiments ◽

Ic50 Values ◽

Set Up

There is an increasing interest in developing natural methods to replace the current chemicals used for maintaining postharvest quality of citrus fruits. The essential oil antifungal activity of mint (MEO), basil (BEO), and lavender (LEO) acting as the vapor-phases was tested against Penicillium digitatum. The minimum doses with fungistatic and fungicidal effect, in vitro, acting as the vapor-phases, were set up. The minimum fungicidal dose was 300 μL for BEO and 350 μL LEO, while for MEO only minimal dose with fungistatic effect was reached. The IC50 values were calculated and used (v/v) for testing preservation of lemon fruits, in close space enriched in vapor oil. For this purpose, the following two independent in vivo experiments were carried out: experiment 1, inoculated lemons with P. digitatum stored without chemical treatments 7 days, at 22 ± 2 °C, at two concentrations (C1—IC50 equivalent; C2—half of C1); and experiment 2, the non-inoculated lemons kept under the same conditions and concentrations of EO vapor served to evaluate the lemon quality properties. The results showed that antifungal protective effect was provided in the order of LEO-C1 > BEO-C1 > MEO-C1 > BEO-C2 > MEO-C2 > LEO-C2. The quality indicators like weight loss, pH, and firmness were not negatively influenced.

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Management of Alternaria leaf blight in tomato plants by mentha essential oil

Plant Protection Science ◽

10.17221/100/2019-pps ◽

2020 ◽

Vol 56 (No. 3) ◽

pp. 191-196

Author(s):

Kahkashan Perveen ◽

Najat A. Bokhari

Keyword(s):

Antifungal Activity ◽

Essential Oil ◽

Mycelial Growth ◽

Leaf Blight ◽

In Vitro Test ◽

Tomato Plants ◽

Conidia Germination ◽

Alternaria Leaf Blight

The essential oil obtained by the hydro-distillation of the leaves of Mentha arvensis Linnaeus was evaluated for its antifungal activity against the causal agent of the Alternaria blight of tomatoes, i.e., Alternaria alternata (Fries) Keissler. The antifungal activity of the mentha essential oil was assessed both in vitro and in vivo. The chemical composition of the mentha oil was also identified by GCMS analysis. The in vitro test revealed that the maximum inhibition in the mycelial growth (93.6%) and conidia germination (90.6%) was at the highest concentration (40 µL/mL), furthermore, it was found that the inhibition of the mycelial growth and conidia germination was dose dependent. The in vivo test proved that the application of the mentha essential oil (40 µL/mL) significantly increased the plant height (84.6%), fresh weight (81.5%) and dry weight (80.0%) when compared to the untreated tomato plants. The disease incidence was 3.5 in the untreated plants, while it was 0.93 for the mentha essential oil treated plants and was 0.08 in the carbendazim treated plants. The GC-MS analysis of the mentha essential oil identified 18 compounds in total, among which the percentage of menthol was the highest (69.2%). The mentha essential oil was successful in managing the Alternaria leaf blight in the tomato plants. Therefore, it can be explored further for the development of a natural fungicide.

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Effect of Allium fistulosum Extract on Ralstonia solanacearum Populations and Tomato Bacterial Wilt

Plant Disease ◽

10.1094/pdis-07-11-0601 ◽

2012 ◽

Vol 96 (5) ◽

pp. 687-692 ◽

Cited By ~ 20

Author(s):

Péninna Deberdt ◽

Benjamin Perrin ◽

Régine Coranson-Beaudu ◽

Pierre-François Duyck ◽

Emmanuel Wicker

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Management Strategies ◽

Antimicrobial Effect ◽

Allium Fistulosum ◽

Inhibition Assay ◽

In Vivo Experiments ◽

Tomato Bacterial Wilt

To control bacterial wilt (Ralstonia solanacearum, phylotype IIB/4NPB), the antimicrobial effect of Allium fistulosum aqueous extract was assessed as a preplant soil treatment. Three concentrations of extract (100, 50, and 25%, 1:1 [wt/vol]) were evaluated by in vitro inhibition assay and in vivo experiments in a growth chamber. In vitro, A. fistulosum (100 and 50%) suppressed growth of R. solanacearum. Preplant treatment of the soil with A. fistulosum extract significantly reduced the R. solanacearum populations. No pathogen was detected in the soil after treatment with 100% concentrated extract from the third day after application until the end of the experiment. A. fistulosum also significantly reduced the incidence of tomato bacterial wilt. In the untreated control, the disease affected 61% of the plants whereas, with 100 and 50% extracts, only 6 and 14% of the plants, respectively, were affected. These results suggest that A. fistulosum extracts could be used in biocontrol-based management strategies for bacterial wilt of tomato.

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Sustainable Management of Soil-Borne Bacterium Ralstonia solanacearum In Vitro and In Vivo through Fungal Metabolites of Different Trichoderma spp.

Sustainability ◽

10.3390/su13031491 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1491

Author(s):

Yancui Guo ◽

Zhenyu Fan ◽

Xiong Yi ◽

Yuhong Zhang ◽

Raja Asad Ali Khan ◽

...

Keyword(s):

Bacterial Wilt ◽

Bacterial Population ◽

Sem Analysis ◽

Wilt Disease ◽

Fungal Metabolites ◽

Trichoderma Spp ◽

Tomato Plants ◽

Bacterial Wilt Disease

The efficacy of traditional control measures for the management of plant pathogens is decreasing, and the resistance of these pathogens to pesticides is increasing, which poses a serious threat to global food security. The exploration of novel and efficient management measures to combat plant disease is an urgent need at this time. In this study, fungal metabolites from three Trichoderma spp. (T. harzianum, T. virens and T. koningii) were prepared on three different growth media (STP, MOF and supermalt (SuM)). The fungal metabolites were tested in vitro and in vivo from March–April 2020 under greenhouse conditions in a pot experiment utilizing completely randomized design to test their management of the bacterial wilt disease caused by R. solanacearum in tomato plants. The effect of the fungal metabolites on bacterial cell morphology was also investigated through scanning electron microscopy (SEM) analysis. In vitro investigation showed that the fungal metabolites of T. harzianum obtained on the STP medium were the most effective in inhibiting in vitro bacterial growth and produced a 17.6 mm growth inhibition zone. SEM analysis confirms the rupture of the cell walls and cell membranes of the bacterium, along with the leakage of its cell contents. Generally, fungal metabolites obtained on an STP medium showed higher activity than those obtained on the other two media, and these metabolites were then evaluated in vivo according to three application times (0 days before transplantation (DBT), 4 DBT and 8 DBT) in a greenhouse trial to examine their ability to manage R. solanacearum in tomato plants. Consistent with in vitro results, the results from the greenhouse studies showed a level of higher anti-bacterial activity of T. harzianum metabolites than they did for the metabolites of other fungi, while among the three application times, the longest time (8 DBT) was more effective in controlling bacterial wilt disease in tomato plants. Metabolites of T. harzianum applied at 8 DBT caused the maximum decrease in soil bacterial population (1.526 log cfu/g), resulting in the lowest level of disease severity (area under disease progressive curve (AUDPC) value: 400), and maximum plant freshness (with a resulting biomass of 36.7 g, a root length of 18.3 cm and a plant height of 33.0 cm). It can be concluded that T. harzianum metabolites obtained on an STP medium, when applied after 8 DBT, can suppress soil bacterial population and enhance plant growth, and thus can be used as a safe, environmentally-conscious and consumer-friendly approach to managing bacterial wilt disease in tomato plants and possibly other crops.

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Effects of developed thyme and oregano essential oil formulations on Monilinia laxa and Monilinia fructicola

Pesticidi i fitomedicina ◽

10.2298/pif2001049t ◽

2020 ◽

Vol 35 (1) ◽

pp. 49-56

Author(s):

Brankica Tanovic ◽

Jovana Hrustic ◽

Milica Mihajlovic ◽

Mila Grahovac ◽

Marija Stevanovic ◽

...

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Antimicrobial Properties ◽

Monilinia Fructicola ◽

Monilinia Laxa ◽

Oregano Essential Oil ◽

In Vivo Experiments ◽

Apple Fruits

Essential oils have been well-known for their antimicrobial properties for a very long time. Some of them have been effectively used in human medicine for decades. Our earlier investigation revealed a great potential of thyme and oregano essential oils as crop protectants against some postharvest fruit pathogens. The effects of formulated thyme and oregano essential oils on Monilinia laxa and Monilinia fructicola were studied in vitro and in vivo. In vitro antagonistic assays were performed on solidified PDA medium using a slightly modified agar overlay technique, while in vivo experiments were conducted on inoculated apple fruits. In vitro essays showed that the developed formulations (emulsifiable concentrates - EC) significantly inhibited the mycelial growth of Monilinia spp. Experiments in vivo, performed on inoculated apple fruits, revealed that the developed formulations provided a significant level of Monilinia spp. suppression. To our knowledge, another EC formulation of oregano essential oil intended for use in Monilinia spp. control has never been developed before. The presented results are initial findings and evaluation of the activity of the developed products should therefore proceed under field conditions to determine their efficacy and activity spectrum, and to estimate economic aspects of their use.

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Efficacy of the Biopesticide NECO in the control of Ralstonia solancearum, causal agent of tomato bacterial wilt in Côte d’Ivoire

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v11i.8813 ◽

2020 ◽

Vol 11 ◽

pp. 138-145

Author(s):

N’guessan Aya Carine ◽

Camara Brahima ◽

Amari Ler N’Ogn Dadé Georges Elisée ◽

Doumbouya Mohamed ◽

Pakora Gilles Alex ◽

...

Keyword(s):

Bacterial Wilt ◽

Ralstonia Solanacearum ◽

Control Agent ◽

Soilborne Pathogens ◽

Tomato Crop ◽

Tomato Plants ◽

Control Approach ◽

Bacterial Growth Inhibition

The tomato crop is confronted to numerous soilborne pathogens, including Ralstonia solanacearum, which considerably limits its production. In order to control this bacterium, a biological control approach has been considered by evaluating the efficacy of the NECO biopesticide against this bacteriosis. In vitro confrontations were carried out using a range of five concentrations of the biopesticide. In vivo, NECO solutions of 5 and 10 mL/L were incorporated into soil previously infested with R. solanacearum before transplanting tomato plants. Zones of bacterial growth inhibition were observed after the application of the NECO biopesticide. Results showed that the 20 mL/L concentration resulted in a higher inhibition rate. The biopesticide at the 10 mL/L concentration significantly reduced the incidence of bacterial wilt (54.05%) under in vivo conditions. The NECO biopesticide could be used as a control agent for Ralstonia solanacearum.

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Effect of Piriformospora indica and Sebacina vermifera on plant growth and essential oil yield in Thymus vulgaris in vitro and in vivo experiments

Symbiosis ◽

10.1007/s13199-010-0104-0 ◽

2011 ◽

Vol 53 (1) ◽

pp. 29-35 ◽

Cited By ~ 17

Author(s):

Hossein Kari Dolatabadi ◽

Ebrahim Mohammadi Goltapeh ◽

Ahmad Moieni ◽

Kamkar Jaimand ◽

Babak Pakdaman Sardrood ◽

...

Keyword(s):

Essential Oil ◽

Plant Growth ◽

Piriformospora Indica ◽

Oil Yield ◽

Thymus Vulgaris ◽

In Vivo Experiments ◽

Sebacina Vermifera ◽

Essential Oil Yield

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In Vitro and In Vivo Inhibition of Cylindrocladium reteaudii by Essential Oils of Acorus calamus Rhizomes

Environment and Natural Resources Journal ◽

10.32526/ennrj/19/2020076 ◽

2020 ◽

Vol 19 (1) ◽

pp. 34-42

Author(s):

Phanin Sintawarak ◽

◽

Suwimon Uthairatsamee ◽

Tharnrat Keawgrajang ◽

◽

...

Keyword(s):

Antifungal Activity ◽

Essential Oil ◽

Essential Oils ◽

Fungal Growth ◽

Antifungal Compound ◽

Acorus Calamus ◽

In Vivo Experiments ◽

Oil Concentration

Cylindrocladium reteaudii (Bugnic.) Boesew. is a severe pathogen which can cause leaf blight disease in Eucalyptus seedlings in tropical countries. This study investigated the antifungal activity of essential oils extracted from Acorus calamus L. rhizomes in inhibiting the growth of C. reteaudii, both in in vitro and in vivo experiments. The extraction of essential oils from rhizomes was carried out by hydro-distillation technique and the in vitro antifungal testing was done by using the poisoned food technique. The results indicated that an essential oil concentration of 2,000 ppm can completely inhibit the fungal growth with a 50% inhibitory concentration value of 54.76 ppm. For the in vivo experiment, it was found that an essential oil concentration of 500 ppm and Captan® of 1,000 ppm were not significantly different in inhibiting the growth of C. reteaudii. However, these two treatments significantly inhibited the fungal growth (p<0.05) when compared with the control treatments. Physiological and anatomical characteristics were investigated to check for the antifungal activity after the application of essential oils. Results showed that essential oil spraying had no effect on the leaf transpiration rate and temperature of the Eucalyptus seedlings, but the incident disease ratio was high when an essential oil concentration of more than 1,500 ppm was applied. Therefore, it can be inferred that the essential oils from A. calamus rhizomes at an optimum concentration can be an efficient antifungal compound with a potential to control leaf and shoot blight diseases in Eucalyptus seedlings in a nursery.

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