Tomato Gray Mold Research Articles

Efficacy of conventional fungicides in controlling tomato grey mold

One of the important diseases of tomato plants is grey mold, which is caused by Botrytis cinerea. In this research, the effects of 10 fungicides on mycelial growth and conidia germination of B. cinerea were investigated. Results showed that carbendazim with a median inhibitory concentration (IC50) value of 0.1 mg/L had the highest inhibitory effect and bordeaux mixture with an IC50 value of 1096.9 mg/L had the lowest inhibitory effect. Benomyl with an IC50 value of 0.04 mg/L had the most visual effects, after 3 and 7 days, on mycelial growth of B. cinerea. The effect of fungicides on preventing fruit wound development caused by B. cinerea was investigated, too. In benomyl treatment, wound diameter on the fruits was 0.73 mm and in copper oxychloride treatment was 6.16 mm, showing the highest and the lowest effective fungicides in the prevention of wound expansion. Different strains of the fungus were collected from various areas in Isfahan province and the effect of the fungicides on their conidial germination was evaluated. Results revealed that the collected isolates had different susceptibility to the 10 tested fungicides.

Chitosan Controls Postharvest Decay on Cherry Tomato Fruit Possibly via the Mitogen-Activated Protein Kinase Signaling Pathway.

The inhibitive effects of chitosan on gray mold caused by Botrytis cinerea on cherry tomato fruit were evaluated. Decay incidence was tested on tomato stored at 22 °C. Hydrogen peroxide accumulation, malondialdehyde (MDA) production, peroxidase (POD) activity, and several related gene expressions (including MPK3, MPK6, PR1a1, and PR5) were determined. Results showed that 0.2% of chitosan solution significantly inhibited the tomato gray mold 3 days after inoculation. Hydrogen peroxide accumulated in the fruit epidermal peel along with chitosan treatment, while MDA production was not increased. POD activity was remarkably enhanced by the application of chitosan. The relative expressions of MPK3, MPK6, and PR1a1 were significantly induced in 10 min after chitosan treatment, while PR5 was induced in 20 min. These findings suggested that the effects of chitosan on inhibiting gray mold in cherry tomato fruit were probably associated with the mitogen-activated protein kinase (MAPK) signaling pathway.

DegQ regulates the production of fengycins and biofilm formation of the biocontrol agent Bacillus subtilis NCD-2

Bacillus subtilis NCD-2 is an excellent biocontrol agent for tomato gray mold and cotton soil-borne diseases. The fengycin lipopeptides serve as a major role in its biocontrol ability. A previous study revealed that insertion of degQ with the mini-Tn10 transposon decreased the antifungal activity of strain NCD-2 against the growth of Botrytis cinerea. To clarify the regulation of degQ on the production of fengycin, we deleted degQ by in-frame mutagenesis. Compared with the wild-type strain NCD-2, the degQ-null mutant had decreased extracellular protease and cellulase activities as well as antifungal ability against the growth of B. cinerea in vitro. The lipopeptides from the degQ-null mutant also had significantly decreased antifungal activity against B. cinerea in vitro and in vivo. This result was confirmed by the decreased fengycin production in the degQ-null mutant that was detected by fast protein liquid chromatography analysis. Quantitative reverse transcription PCR further demonstrated that degQ positively regulated the expression of the fengycin synthetase gene. In addition, the degQ-null mutant also had a flatter colony phenotype and significantly decreased biofilm formation ability relative to the wild-type strain. All of those characteristics from degQ-null mutant could be restored to the strain NCD-2 wild-type level by complementation of intact degQ in the mutant. Therefore, DegQ may be an important regulator of fengycin production and biofilm formation in B. subtilis NCD-2.

Identification and Characterization of Novel Biocontrol Bacterial Strains

Because bacterial isolates from only a few genera have been developed commercially as biopesticides, discovery and characterization of novel bacterial strains will be a key to market expansion. Our previous screen using plant bioassays identified 24 novel biocontrol isolates representing 12 different genera. In this study, we characterized the 3 isolates showing the best biocontrol activities. The isolates were Pantoea dispersa WCU35, Proteus myxofaciens WCU244, and Exiguobacterium acetylicum WCU292 based on 16S rRNA sequence analysis. The isolates showed differential production of extracellular enzymes, antimicrobial activity against various fungal or bacterial plant pathogens, and induced systemic resistance activity against tomato gray mold disease caused by Botrytis cinerea. E. acetylicum WCU292 lacked strong in vitro antimicrobial activity against plant pathogens, but induced systemic resistance against tomato gray mold disease. These results confirm that the trait of biological control is found in a wide variety of bacterial genera.

Complete Genome Sequence of Bacillus subtilis BAB-1, a Biocontrol Agent for Suppression of Tomato Gray Mold

Bacillus subtilis BAB-1, isolated from cotton rhizosphere soil, is an excellent biocontrol agent for tomato gray mold. The genome of B. subtilis strain BAB-1 was fully sequenced and annotated, genes encoding the antifungal active compound were identified, and multiple sets of regulatory systems were found in the genome.

Control of Botrytis cinerea and Postharvest Quality of Cut Roses by Electron Beam Irradiation

The present study was conducted to determine the effect of electron beam irradiation on control of Botrytis cinerea and postharvest quality of cut roses. Electron beam doses of 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 10, and 20 kGy were applied with a 10-MeV linear electron beam accelerator (EB Tech, Korea). Electron beams inhibited spore germination and mycelial growth of B. cinerea with increasing irradiation doses. Conidia of B. cinerea were more tolerant to irradiation than were mycelia: the effective irradiation doses for 50% inhibition (ED 50 ) of spore germination and mycelial growth were 2.02 kGy and 0.89 kGy, respectively. In addition, electron beam irradiation was more effective in reducing mycelial growth of B. cinerea at 10℃ than at 20℃. Analysis of in vivo antifungal activity revealed that elevated irradiation doses exhibited increased control efficacy for tomato gray mold. Flower longevity and fresh weight of cut roses decreased when the irradiation dose was increased. In addition, flower bud opening tended to be inhibited in a dose-dependent manner. Although ‘Decoration’, ‘Il se Bronze’, ‘Queen Bee’, and ‘Revue’ roses tolerated and maintained overall postharvest quality up to 0.4 kGy, ‘Vivian’ did not, demonstrating that the irradiation sensitivity of cut roses varies according to cultivar.

Analysis of Clonostachys rosea-induced resistance to tomato gray mold disease in tomato leaves.

Tomato gray mold disease, caused by Botrytis cinerea, is a serious disease in tomato. Clonostachys rosea is an antagonistic microorganism to B. cinerea. To investigate the induced resistance mechanism of C. rosea, we examined the effects of these microorganisms on tomato leaves, along with changes in the activities of three defense enzymes (PAL, PPO, GST), second messengers (NO, H2O2, O2 −) and phytohormones (IAA, ABA, GA3, ZT, MeJA, SA and C2H4). Compared to the control, all treatments induced higher levels of PAL, PPO and GST activity in tomato leaves and increased NO, SA and GA3 levels. The expression of WRKY and MAPK, two important transcription factors in plant disease resistance, was upregulated in C. rosea- and C. rosea plus B. cinerea-treated samples. Two-dimensional gel electrophoresis analysis showed that two abundant proteins were present in the C. rosea plus B. cinerea-treated samples but not in the other samples. These proteins were determined (by mass spectrum analysis) to be LEXYL2 (β-xylosidase) and ATP synthase CF1 alpha subunit. Therefore, C. rosea plus B. cinerea treatment induces gray mold resistance in tomato. This study provides a basis for elucidating the mechanism of C. rosea as a biocontrol agent.

Inhibitory effect of Xenorhabdus nematophila TB on plant pathogens Phytophthora capsici and Botrytis cinerea in vitro and in planta.

Entomopathogenic bacteria Xenorhabdus spp. produce secondary metabolites with potential antimicrobial activity for use in agricultural productions. This study evaluated the inhibitory effect of X. nematophila TB culture on plant pathogens Botrytis cinerea and Phytophthora capsici. The cell-free filtrate of TB culture showed strong inhibitory effects (>90%) on mycelial growth of both pathogens. The methanol-extracted bioactive compounds (methanol extract) of TB culture also had strong inhibitory effects on mycelial growth and spore germinations of both pathogens. The methanol extract (1000 μg/mL) and cell-free filtrate both showed strong therapeutic and protective effects (>70%) on grey mold both in detached tomato fruits and plants, and leaf scorch in pepper plants. This study demonstrates X. nematophila TB produces antimicrobial metabolites of strong activity on plant pathogens, with great potential for controlling tomato grey mold and pepper leaf scorch and being used in integrated disease control to reduce chemical application.

The global regulator GacS regulates biofilm formation in Pseudomonas chlororaphis O6 differently with carbon source

An aggressive root colonizer, Pseudomonas chlororaphis O6 produces various secondary metabolites that impact plant health. The sensor kinase GacS is a key regulator of the expression of biocontrol-related traits. Biofilm formation is one such trait because of its role in root surface colonization. This paper focuses on the effects of carbon source on biofilm formation. In comparison with the wild type, a gacS mutant formed biofilms at a reduced level with sucrose as the major carbon source but at much higher level with mannitol in the defined medium. Biofilm formation by the gacS mutant occurred without phenazine production and in the absence of normal levels of acyl homoserine lactones, which promote biofilms with other pseudomonads. Colonization of tomato roots was similar for the wild type and gacS mutant, showing that any differences in biofilm formation in the rhizosphere were not of consequence under the tested conditions. The reduced ability of the gacS mutant to induce systemic resistance against tomato leaf mold and tomato gray mold was consistent with a lack of production of effectors, such as phenazines. These results demonstrated plasticity in biofilm formation and root colonization in the rhizosphere by a beneficial pseudomonad.

Biocontrol Activity of Bacillus amyloliquefaciens CNU114001 against Fungal Plant Diseases

A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition.

토마토 잿빛곰팡이병균 약제저항성 간이 판별법

Botrytis 선택배지(BSM)를 이용하여 토마토 포장에서 꽃잎의 감염시기를 착과 직후, 착과 25일 후, 착과 45일 후로 나누어 조사하였던 바 착과 직후의 꽃잎에서는 65%의 감염률을 보였으나 착과 25일 후의 꽃잎에서는 87%, 45일 후의 꽃잎에서는 100%의 감염률을 보였다. 착과 후 시간이 지날수록 잿빛곰팡이병균의 꽃잎 감염율은 증가하였다. 한편, 토마토 품종별 꽃잎의 감염시기를 개화 전, 개화 후, 착과 후로 구분하여 조사하였던 바 전체적으로 개화 전에 비하여 개화 후 시간이 지날수록 감염율이 급격히 증가하였으며, 일반토마토 3품종의 감염율이 방울토마토에 비하여 현저히 높았다. 즉 일반토마토의 착과 후 꽃잎 감염율이 70~80%인데 비하여 방울토마토의 꽃잎 감염율은 20~45%였다. 일반토마토 및 방울토마토 포장에서 잿빛곰팡이병균의 포자 비산량을 BSTM을 이용하여 조사한 결과 토마토 생육기간이 길어질수록 비산 포자량은 증가하였으며 특히 일반 토마토품종에서 잿빛곰팡이병의 발생 이후에 급격하게 증가하였다. 그러나 포장 내의 병원균 포자비산량의 증가에도 불구하고 방울토마토는 잿빛곰팡이병의 발병이 매우 적었다. BSM 및 BSTM을 이용한 잿빛곰팡이병 약제저항성균 간이검정법의 포장 적용시험을 통하여 바 이들의 활용가능성을 확인하였으며, 부여 및 익산지역 12농가에서 8개 약제를 공시하여 실증시험을 실시하였던 바 fluazinam 및 diethofencarb+carbendazim 혼합제가 주로 방제에 적합한 약제로 판정되었다. BSM을 이용한 kit는 잿빛곰팡이병이 발생하기 이전에 조기에 약제 저항성 병원균 판별이 가능하나 8개의 약제배지에 접종할 경우 2시간 정도의 시간이 필요하다. BSTM을 활용한 kit는 배지를 설치 후 24시간이 지난 후 수거하기 때문에 사용은 간편하나 잿빛곰팡이병이 발생하기 이전에 설치하면 낙하 포자량이 적어 약제저항성균 판별에 어려움이 있을 것이라 생각된다. 【Grey mold infection rate in tomato was investigated with the inoculation of dead flowers on Botrytis selective media. The grey mold infection rate of flower after fruiting were higher in the order of after 45 days, after 25 days, and fruiting day with 100%, 87% and 65%, respectively. The number of infected flowers were increased with time increase after the flowering before fruiting. BSM (Botrytis selective medium) was used to check grey mold infection rate depending on the flowering stage and cultivar. Grey mold infection rate depending on the flowering stage was similar in all the beef-tomato cultivar as 1.5~5% at preflowering, 1.5~45% at flowering and 75~90% at fruiting. On the other hand, cherry tomato cultivar KoKo had lower infection rates of 0~3.5% at pre-flowering, 10~30% at flowering and 20~50% at fruiting. These resulted from the fact that beaf-tomato cultivar have much bigger flowers and larger amount of pollens compared to those of cherry tomato cultivar. The amounts of falling pollens of Botrytis spp. were checked for beaf-tomato cultivar and cherry tomato cultivar using BSTM. The amounts of falling pollens were increased as growth period was extended, and the amount of spores increased rapidly during the outbreak of grey mold. Twelve field trials in Buyeo and Iksan areas showed that Fluazinam, and Diethofencarb+Carbendazim were effective fungicides to control tomato grey mold, and these results were similar to those of field trials with BSTM. This is the first report of Fluazinam as a effective fungicide for the control of grey mold of tomato even though it has not been registered yet for the control of gray mold in tomato.】

Lipopeptides, a novel protein, and volatile compounds contribute to the antifungal activity of the biocontrol agent Bacillus atrophaeus CAB-1

Bacillus atrophaeus CAB-1 displays a high inhibitory activity against various fungal pathogens and suppresses cucumber powdery mildew and tomato gray mold. We extracted and identified lipopeptides and secreted proteins and volatile compounds produced by strain CAB-1 to investigate the mechanisms involved in its biocontrol performance. In vitro assays indicated all three types of products contributed to the antagonistic activity against the fungal pathogen Botrytis cinerea. Each of these components also effectively prevented the occurrence of the cucumber powdery mildew caused by Sphaerotheca fuliginea under greenhouse conditions. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry revealed that the major bioactive lipopeptide was fengycin A (C15-C17). We isolated the crude-secreted proteins of CAB-1 and purified a fraction with antifungal activity. This protein sequence shared a high identity with a putative phage-related pre-neck appendage protein, which has not been reported as an antifungal factor. The volatile compounds produced by CAB-1 were complex, including a range of alcohols, phenols, amines, and alkane amides. O-anisaldehyde represented one of the most abundant volatiles with the highest inhibition on the mycelial growth of B. cinerea. To our knowledge, this is the first report on profiling three types of antifungal substances in Bacilli and demonstrating their contributions to plant disease control.

The Research of Inhibition Mechanism and the Application on <i>Botrytis cinerea</i> of 5% Potash Alum Water Solution

Botrytis cinerea is a necrotrophic fungus that affects many plant species requiring new methods of control. In the present investigation, efficacy of potash alum, a traditionally known double salt in Indian and Chinese medicine system, was tested against fourteen plant pathogenic fungi, inhibition mechanism and field efficacy of 5% potash alum water solution (M1) against tomato gray mold caused by B. cinerea. The inhibition spectrum tests showed that M1 had some inhibition effect against fourteen pathologic fungi by adopting mycelium growth rate method. M1 had an inhibition rate of 81.5%, 100%, 100% and 93.58% against B. clnerea, P. aphanidermatum, F. equiset and S. sclerotiorum respectively. M1 could effectively inhibit mycelial growth, spores production and germination of B. cinerea. The results preliminary showed that M1 had no effect on tomato growth. Tomato gray mold caused by B. cinerea had effectively been prevented by using M1 with field efficacy, which control effect was 78.66%. So the study lay the groundwork for further research and application.

호장근(Reynoutria elliptica)으로부터 항균활성 물질의 분리 및 구조결정

In the continued research on natural fungicides for the control of plant diseases by using plant-derived products, we found that Reynoutria elliptica. had a strong fungicidal activity against several plant pathogens. R. elliptica (3.2 ㎏) were extracted with 80% aq. MeOH and the concentrated extracted was partitioned with n-hexane, EtOAc, n-BuOH and H₂O successively. The four layers were tested their disease control efficacies against 4 plant disease such as rise blast (RCB), tomato grey mold (TGM), tomato late blight (TLB), and barly powdery mildew (BPM). The n-hexane fraction was highly active showing over 95% control against TLB and BPM. and the EtOAc fraction was highly active showing over 95% control against RCB, TLB, and BPM. By using silica gel chromatography, MPLC, and HPLC, three compounds that were expected to have antifungal activity were isolated. Their chemical structures were elucidated as physcion, emodin, and emodie-8-O-glucoside by EI-MS and NMR spectroscopic analyses.

계혈등(Spatholobus suberectus Dunn)으로부터 항균활성 물질의 분리 및 구조결정

In the continued research on natural fungicides for control of plant diseases by using plant- derived products, we found that Spatholobus suberectus Dunn had a strong fungicidal activity against several plant pathogens. S. suberectus (1 kg) was extracted with 80% aqueous MeOH and then the concentrated extract was partitioned with n-hexane, EtOAc, n-BuOH and H2O successively. The four layers were tested their disease contron efficacies against 6 plant diseases such as rice blast (RCB), rice sheath blight (RSB), tomato grey mold (TGM), tomato late blight (TLB), wheat leaf rust (WLR), and barley powdery mildew (BPM). The EtOAc fraction was highly active showing over 80% control against RCB, TGM, TLB, and BPM. By using silica gel chromatography, preparative TLC and HPLC, six compounds that were expected to have antifungal activity were separated. Their chemical structures were identified as ethanone, hydroxytyrosol, epicatechin, procyanidin B2, dimethoxy daizein and formononetin by ESI-MS, 1 H-NMR, 13 C-NMR, and 2D- NMR spectroscopic analyses. The chemicals except epicatechin were first reported in S. suberectus. Study on in vitro and in vivo antifungal activities of the isolated compounds is in progress.

In Vivo Antifungal Activities of the Methanol Extracts of Invasive Plant Species Against Plant Pathogenic Fungi

Plants are the promising reservoirs for natural products with their diverse secondary metabolites. Many invasive plants have been introduced in Korea, which adversely affect on the native ecosystem but holds difficulty removing them due to their proliferation. In this study, we evaluated disease control efficacy of methanol extracts from four invasive plant species against 7 representative crop pathogens. Methanol extract of Phytolacca americana effectively suppressed rice blast, tomato gray mold, and tomato late blight in a dose dependent manner. The methanol extract of Amorpha fruticosa also exhibited potent antifungal activity against pepper anthracnose in a concentration dependent way. These data suggest that the extracts of P. americana and A. fruticosa can be developed as plant disease protection agents against rice blast, tomato gray mold, tomato late blight, and pepper anthracnose. Furthermore, more extensive research will be required to identify and isolate active compounds from problematic invasive plant species to develop valuable agrochemicals.

Effect of plant-based fungicide coated compound fertilizer on tomato growth, nitrogen use efficiency and disease incidence

利用植物源杀菌材料作为包衣剂研制出杀菌包膜复合肥, 在番茄小区试验中研究了其杀菌及对番茄生长的影响。结果表明: 各杀菌包膜复合肥处理(分别用ZYF1~ ZYF5 表示)均能有效延缓养分的释放, 与施普通复合肥处理(CK1)相比各杀菌包膜复合肥处理土壤硝态氮在番茄生长后期仍能保持较高含量。除ZYF4 处理外, 其余杀菌包膜复合肥处理番茄产量均明显高于CK1, 其中ZYF3 处理番茄产量最高, 达11.1 kg·m^-2, 较CK1 高16.8%。各杀菌包膜复合肥处理的氮肥利用率也均大于CK1(33.3%), 其中ZYF2、ZYF3 处理分别较CK1 处理高9.9 个和9.5 个百分点。各杀菌包膜复合肥对番茄的Vc 含量无显著影响, ZYF1 处理显著降低了番茄的硝酸盐含量, 而ZYF2、ZYF4、ZYF5 处理则促进了番茄对硝酸盐的累积。各杀菌包膜复合肥处理显著降低了番茄枯萎病、灰霉病的发病率, 其中ZYF1 处理对这两种病菌均有较高的抑制作用, 使发病率较CK1 分别下降17.7 个和12.5 个百分点。

Biological control of leaf grey mould of greenhouse tomatoes caused by Botrytis cinerea

Botrytis cinerea (grey mould) is one of the most common diseases of glasshouse crops and is a major cause of plant death in long-season tomato production. A disease management field trial was conducted in a commercial tomato production greenhouse for comparison of seven fungal antagonists which had previously exhibited potential as biological control agents with respect to Botrytis cinerea incidence and severity. Isolates of Trichoderma harzianum, Candida pelliculosa, Rhodotorula rubra, and Fusarium semitectum were recovered from leaves, fruits and flowers of different solanaceous plants. The fungal antagonists were tested for their control of leaf grey mould on tomato under greenhouse conditions during 2008 and 2009. In both years, foliar spray with strains of Trichoderma harzianum and Fusarium semitectum suppressed the foliar infection of B. cinerea. The suspensions of T. harzianum 118 and 252 and F. semitectum 25 significantly reduced disease incidence (65–95%) and severity (50–77%) in inoculated plants compared to untreated controls (P ≤ 0.05). Our results suggest that formulations of saprophytic fungi selected from the naturally occurring mycoflora could be an effective tool in the biological control of tomato grey mould.

Antifungal Activity of Lower Alkyl Fatty Acid Esters against Powdery Mildews

In the course of a searhing environmental friendly antifungal compounds, we found that mixture of methyl esters of fatty acids obtained from soybean oil had potent control efficacy against barley powdery mildew (Blumeria graminis f. sp. hordei). In this study, ten alkyl fatty acid esters (AFAEs) were tested for in vivo antifungal activity against five plant diseases such as rice blast, rice sheath blight, tomato gray mold, tomato late blight and barley powdery mildew. Some AFAEs showed the most control efficacy against barley powdery mildew among the tested plant diseases. By 5-hr protective and 1-day curative applications, six AFAEs (<TEX>$3,000\;{\mu}g/ml$</TEX>), including methyl and ethyl palmitates, methyl and ethyl oleates, methyl linoleate, and methyl linolenate demonstrated both curative and protective activities against barley powdery mildew. In contrary, methyl laurate strongly controlled the development of powdery mildew on barley plants by curative treatment at a concentration of <TEX>$333\;{\mu}g/ml$</TEX>, but did not show protective activity even at <TEX>$3,000\;{\mu}g/ml$</TEX>. Under greenhouse conditions, the seven AFAEs (<TEX>$1,000\;{\mu}g/ml$</TEX>) except for methyl and ethyl stearates, and methyl caprylate also effectively controlled cucumber powdery mildew caused by Podosphaera xanthii. Among them, methyl and ethyl palmitates (<TEX>$333\;{\mu}g/ml$</TEX>) represented the most control activity of more than 68% against the disease. The results are the first report on the antifungal activity of methyl and ethyl esters of fatty acids against plant pathogenic fungi.

In vitro and in vivo antifungal activities of the essential oils of various plants against tomato grey mould disease agent Botrytis cinerea

The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating fungal pathogen Botrytis cinerea, the causal agent of grey mould disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic plants, which belong to the Lamiacea family such as origanum ( Origanum syriacum L. var. bevanii), lavender ( Lavandula stoechas L. var. stoechas) and rosemary ( Rosmarinus officinalis L.), were investigated against B. cinerea. Contact and volatile phase effects of different concentrations of the essential oils were found to inhibit the growth of B. cinerea in a dose-dependent manner. Volatile phase effects of essential oils were consistently found to be more effective on fungal growth than contact phase effect. A volatile vapour of origanum oil at 0.2 μg/ml air was found to completely inhibit the growth of B. cinerea. Complete growth inhibition of pathogen by essential oil of lavender and rosemary was, however, observed at 1.6 μg/ml air concentrations. For the determination of the contact phase effects of the tested essential oils, origanum oil at 12.8 μg/ml was found to inhibit the growth of B. cinerea completely. Essential oils of rosemary and lavender were inhibitory at relatively higher concentrations (25.6 μg/ml). Spore germination and germ tube elongation were also inhibited by the essential oils tested. Light and scanning electron microscopic (SEM) observations revealed that the essential oils cause considerable morphological degenerations of the fungal hyphae such as cytoplasmic coagulation, vacuolations, hyphal shrivelling and protoplast leakage and loss of conidiation. In vivo assays with the origanum essential oil, being the most efficient essential oil, under greenhouse conditions using susceptible tomato plants resulted in good protection against grey mould severity especially as a curative treatment. This study has demonstrated that the essential oils are potential and promising antifungal agents which could be used as biofungicide in the protection of tomato against B. cinerea.