Cucumber Powdery Mildew Research Articles

Curative and Suppressive Activities of Essential Tea Tree Oil against Fungal Plant Pathogens

Timorex Gold based on the essential tea tree oil (TTO) derived from the Australian tea tree oil (Melaleuca alternifolia) plant has demonstrated high efficacy and a strong curative activity against black Sigatoka in banana and controlled it in stages 1, 2, 3, and 4 of disease development. Transmission electron microscope (TEM) examination of infected leaf sections treated with Timorex Gold revealed disruption of the fungal cell membrane and destruction of the fungal cell wall in disease development stages 4 and 5. Mineral oil and the fungicide difenoconazole, when applied alone, had no curative effect and did not disrupt the fungal cell wall or membrane, similar to the untreated control tissue. A single spray of Timorex Gold effectively controlled and suppressed powdery mildew in cucumber by causing the disappearance of 99% of established colonies recorded 1 or 2 days after the application and was effective for up to 8 days after application. Scanning electron microscope (SEM) examination of infected and Timorex Gold-treated leaves indicated strong shrinkage and disruption of fungal hyphae and conidial cells. The curative and suppressive modes of action of the Timorex Gold may explain its success in controlling both diseases.

Optimization of amino acid production from chicken feather by Bacillus amyloliquefaciens using Response surface methodology as a new tool for powdery mildew disease biocontrol.

The present work aimed to optimize amino acids production by Bacillus amyloliquefaciens 35s from chicken feather using response surface methodology (RSM) and applying the produced amino acids in biological control of powdery mildew disease. Variables affecting amino acids production from B. amyloliquefaciens 35s were screened using Plackett Burman design. Factors showed to be significant to produce amino acids were optimized using central composite design (CCD) of RSM at three coded levels (-1, 0, +1). All obtained data were analyzed by ANOVA with post hoc multiple comparison analysis performed using Tukey’s HSD. TGY (tryptone, glucose, yeast extract) was the basal medium. Impacts of medium components were studied using Plackett-Burman design. “Design Expert 12” StateEase was used to analyze the experimental Plackett- Burman design. Feather, yeast extract, CaCO3, KH2PO4 and agitation rate (using shake flask) were optimized statistically by the CCD design of the RSM. Validation of statistical model of the medium components was done by carrying out the experiment at optimum conditions of the process parameters as determined by the model. Amino acids types were identified by amino acid analyzer. Among the significant medium components, feather, yeast extract, CaCO3, KH2PO4 and agitation rate showed to have significant effect on amino acids production. Predicted maximum amino acids production was observed near the mid-point concentrations of the mentioned above factors and the experimental value (6.55 g/l) was very close to the predicted value of (6.60 g/l) predicted by the model. Amino acid analyzer analysis for the produced amino acids shows the release of asparagine, threonine, serine, glutamine, proline, glycine, alanine, cysteine, valine, methionine, isoleucine, leucine, tyrosine, phenyl alanine, histidine, lysine and arginine, respectively. Effect of chicken feather hydrolysate on cucumber powdery mildew disease was tested by applying foliar application with different concentrations (0, 5, 10, 15, and 20% v/v), then degree of infection and sporulation on cucumber plants were assessed. The lowest concentration of chicken feather hydrolysate showed the lowest effect on disease index. Conversely, cucumber resistance increased by the increasing of feather’s hydrolysate concentrations associated with a clear reduction in the disease index and sporulation. Aside from, extra foliar application showed a decrease in the disease index for all concentrations compared with untreated plants. Foliar application with 20% concentration of chicken feather hydrolysate had the highest stimulation of the studied oxidative enzymes i.e., peroxidase (POX), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and superoxide dismutase (SOD).

Comparative transcriptomic analyses of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to identify the genes involved in the resistance to Sphaerotheca fuliginea infection.

BackgroundCucumber (Cucumis sativus L.) is a widely cultivated vegetable crop, and its yield and quality are greatly affected by various pathogen infections. Sphaerotheca fuliginea is a pathogen that causes powdery mildew (PM) disease in cucumber. However, the genes involved in the resistance to PM in cucumber are largely unknown.MethodsIn our study, a cucumber PM resistant cultivated variety “BK2” and a susceptible cultivated variety “H136” were used to screen and identify differential expressed genes (DEGs) under the S. fuliginea infection.ResultsThere were only 97 DEGs between BK2 and H136 under the control condition, suggesting a similarity in the basal gene expression between the resistant and susceptible cultivated varieties. A large number of hormone signaling-related DEGs (9.2% of all DEGs) between resistant and susceptible varieties were identified, suggesting an involvement of hormone signaling pathways in the resistance to PM. In our study, the defense-related DEGs belonging to Class I were only induced in susceptible cultivated variety and the defense-related DEGs belonging to Class II were only induced in resistant cultivated variety. The peroxidase, NBS, glucanase and chitinase genes that were grouped into Class I and II might contribute to production of the resistance to PM in resistant cultivated variety. Furthermore, several members of Pathogen Response-2 family, such as glucanases and chitinases, were identified as DEGs, suggesting that cucumber might enhance the resistance to PM by accelerating the degradation of the pathogen cell walls. Our data allowed us to identify and analyze more potential genes related to PM resistance.

Comparative Studies on Nanosulfur and Certain Fungicides to Control Cucumber Powdery Mildew Disease and their Residues in Treated Fruits

Comparative Studies on Nanosulfur and Certain Fungicides to Control Cucumber Powdery Mildew Disease and their Residues in Treated Fruits

Identification of MicroRNAs and Their Targets That Respond to Powdery Mildew Infection in Cucumber by Small RNA and Degradome Sequencing.

Powdery mildew (PM) is a prevalent disease known to limit cucumber production worldwide. MicroRNAs (miRNAs) are single-stranded molecules that regulate host defense responses through posttranscriptional gene regulation. However, which specific miRNAs are involved and how they regulate cucumber PM resistance remain elusive. A PM-resistant single-segment substitution line, SSSL508-28, was developed previously using marker-assisted backcrossing of the PM-susceptible cucumber inbred D8 line. In this study, we applied small RNA and degradome sequencing to identify PM-responsive miRNAs and their target genes in the D8 and SSSL508-28 lines. The deep sequencing resulted in the identification of 156 known and 147 novel miRNAs. Among them, 32 and six differentially expressed miRNAs (DEMs) were detected in D8 and SSSL508-28, respectively. The positive correlation between DEMs measured by small RNA sequencing and stem-loop quantitative real-time reverse transcription–polymerase chain reaction confirmed the accuracy of the observed miRNA abundances. The 32 DEMs identified in the PM-susceptible D8 were all upregulated, whereas four of the six DEMs identified in the PM-resistant SSSL508-28 were downregulated. Using in silico and degradome sequencing approaches, 517 and 20 target genes were predicted for the D8 and SSSL508-28 DEMs, respectively. Comparison of the DEM expression profiles with the corresponding mRNA expression profiles obtained in a previous study with the same experimental design identified 60 and three target genes in D8 and SSSL508-28, respectively, which exhibited inverse expression patterns with their respective miRNAs. In particular, five DEMs were located in the substituted segment that contained two upregulated DEMs, Csa-miR172c-3p and Csa-miR395a-3p, in D8 and two downregulated DEMs, Csa-miR395d-3p and Csa-miR398b-3p, in SSSL508-28. One gene encoding L-aspartate oxidase, which was targeted by Csa-miR162a, was also located on the same segment and was specifically downregulated in PM-inoculated D8 leaves. Our results will facilitate the future use of miRNAs in breeding cucumber varieties with enhanced resistance to PM.

First report of the occurrence of multiple resistance to Flutianil and Pyriofenone in field isolates of Podosphaera xanthii, the causal fungus of cucumber powdery mildew

Two new fungicides, flutianil and pyriofenone were introduced into the Japanese market in 2013 and 2014, to control powdery mildew on cucumber. Isolates of Podosphaera xanthii, the causal agent of powdery mildew, were collected in Ibaraki Prefecture, Japan, between 2017 and 2019 from cucumber greenhouses with a history of flutianil and pyriofenone usage. They were then tested for sensitivity to both fungicides by the leaf disc test. First, the sensitivity of three baseline reference isolates to each fungicide was determined. Minimum inhibitory concentrations values were 0.0063 μg/ml for flutianil and 10 μg/ml for pyriofenone, while 50% effective concentration (EC50) values of these fungicides were 0.00013–0.00035 μg/ml and 0.39–0.70 μg/ml, respectively. To determine the current sensitivity of P. xanthii in detail, 23 single-spore isolates were then sampled from five greenhouses and tested. Nineteen isolates showed high resistance (Flu-HR/Pyr-HR) with EC50 values of >100 μg/ml for flutianil and > 1000 μg/ml for pyriofenone. The low sensitivity of Flu-HR/Pyr-HR isolates was stable even after 46 subcultures on fungicide-untreated cotyledons. Additionally, two isolates showed moderate resistance (Flu-MR/Pyr-MR) to flutianil (EC50: mean 0.8 μg/ml) and pyriofenone (mean 58.7 μg/ml). The results from foliar inoculation tests on potted cucumber plants confirmed low efficacies of flutianil and pyriofenone against resistant isolates. Among a total of 122 isolates sampled from 13 greenhouses, 89 isolates (73.0%) were categorized as Flu-HR/Pyr-HR and two isolates (1.6%) as Flu-MR/Pyr-MR. This is the first report on flutianil resistance in any pathogen.

Nighttime Application of UV-C to Control Cucumber Powdery Mildew

Nonionizing, ultraviolet (UV) radiation is effective for mitigating powdery mildew associated with a variety of crops including strawberry, grapes, rosemary, tomato, rose, and cucumber. The effectiveness of UV radiation depends upon the dose (irradiance × duration), the frequency of dosing, the time of application, and the sensitivity of the crop to UV radiation. Reported here are the results of two laboratory studies examining the impact of UV-C (254 nm) on cucumber and its obligate powdery-mildew-causing pathogen Podosphaera xanthii. In the first study, doses of UV-C (72 and 144 J m–2) applied every night were more effective at reducing disease severity than dosing every day. However, leaf area was reduced more following nighttime applications than daytime applications, suggesting that both day and night applications of UV-C could compromise yield without necessarily eliminating the disease. The second study showed that a dose of UV-C (7.2 J m–2) applied every night or a higher dose (70 J m–2) applied every fourth night were both effective for eliminating powdery mildew without significantly reducing leaf area. These findings, if confirmed in the field, could provide cucumber growers with additional options for controlling powdery mildew without compromising yield.

The modifications of cell wall composition and water status of cucumber leaves induced by powdery mildew and manganese nutrition

Powdery mildew caused by Podosphaera fuliginea, is one of the most important diseases, damaging cucumber's yield worldwide. Among the different controlling ways, management of plant nutrition is an effective method. The present experiment was aimed to study the effects of foliar application of manganese (Mn) on disease suppression and to elucidate the possible mechanisms by which Mn-treated plants resist to fungal disease. Cucumber plants were hydroponically grown and sprayed by MnSO4 alone and in combination with lysine (Lys) and methionine (Met) four days before pathogen inoculation. The results showed that the foliar application of Mn reduced the fungal disease severity by increasing of lignin, cellulose and pectin contents of cell wall (CW) and improving of leaf water status. The reduction of disease severity by application of MnSO4, Mn + Lys and Mn + Met, were 40, 33, and 40% compared to control, respectively. The increases of lignin contents at the same treatments were 33, 27, and 36%, respectively. The leaf water potential (LWP) enhanced by foliar spray of above-mentioned fertilizers up to 15, 18, and 17%, respectively. The results of present study revealed that the Mn nutrition could control the cucumber powdery mildew by reinforcing of CW structure and reducing of water loss from infected leaves. The current findings are the first reports elucidating the CW-related defense mechanisms in which Mn has important role. The obtained results have a practical importance either in studies of plant physiology and biochemistry or in agricultural sciences for cost-effective control of powdery mildew in cucumber plants.

Comparative proteomic analysis of cucumber powdery mildew resistance between a single-segment substitution line and its recurrent parent

Powdery mildew (PM) is considered a major cause of yield losses and reduced quality in cucumber worldwide, but the molecular basis of PM resistance remains poorly understood. A segment substitution line, namely, SSL508-28, was developed with dominant PM resistance in the genetic background of PM-susceptible cucumber inbred line D8. The substituted segment contains 860 genes. An iTRAQ-based comparative proteomic technology was used to map the proteomes of PM-inoculated and untreated (control) D8 and SSL508-28. The number of differentially regulated proteins (DRPs) in SSL508-28 was almost three times higher than that in D8. Fourteen DRPs were located in the substituted segment interval. Comparative gene expression analysis revealed that nodulin-related protein 1 (NRP1) may be a good candidate for PM resistance. Gene Ontology enrichment analysis showed that DRPs functioning in tetrapyrrole biosynthetic process, sulfur metabolic process and cell redox homeostasis were specifically enriched in the resistant line SSL508-28. DRPs categorized in the KEGG term photosynthesis increased in both lines upon PM infection, suggesting that the strategies used by cucumber may be different from those used by other crops to react to PM attacks at the initial stage. The measurement of hydrogen peroxide and superoxide anion production and net photosynthetic rate were consistent with the changes in protein abundance, suggesting that the proteomic results were reliable. There was a poor correlation between DRPs measured by iTRAQ and the corresponding gene expression changes measured by RNA-seq with the same experimental design. Taken together, these findings improve the understanding of the molecular mechanisms underlying the response of cucumber to PM infection.

Oil Adjuvants Enhance the Efficacy of Pyraclostrobin in Managing Cucumber Powdery Mildew (Podosphaera xanthii) by Modifying the Affinity of Fungicide Droplets on Diseased Leaves.

Adding adjuvants improved the affinity of fungicide droplets to cucumber leaves infected with powdery mildew (Podosphaera xanthii) and subsequent efficacy of fungicide treatments in reducing the disease. The affinity of oil adjuvants was quantified by adhesional tension and "work of adhesion". Oil adjuvant-fungicide mixtures were applied to plants in field experiments to evaluate their effectiveness in disease prevention. Both the adhesional tension and work of adhesion of the adjuvants at selected concentrations increased on powdery-mildew-infected cucumber leaves more than on healthy cucumber leaves. The adjuvant GY-Tmax (GYT) displayed the best surface activity or "surfactivity" in enhancing the affinity and adherence of droplets to powdery-mildew-infected cucumber leaves, while epoxidized soybean oil (ESO), methyl oleate, and biodiesel exhibited much lower effects in terms of the surface tension, contact angle, adhesional tension, and work of adhesion. Field experiments determined that the combination of GYT at 1,000 mg liter-1 and pyraclostrobin (150 g a.i. ha-1) was most effective (91.52%) in controlling cucumber powdery mildew. Pyraclostrobin with ESO was also highly effective (ranging from 77.54 to 89.65%). The addition of oil adjuvants, especially GYT and ESO, to fungicide applications can be an effective strategy to enhance the efficacy of pesticides in controlling plant diseases by modifying the affinity of fungicide droplets to symptomatic leaves.

Synthesis and Fungicidal Activity of (E)-Methyl 2-(2-((1-cyano-2-hydrocarbylidenehydrazinyl)methyl)phenyl)-2-(methoxyimino)acetates.

Strobilurin fungicides are some of the most potent and successful agrochemicals. However, continued use of traditional strobilurins has led to the emergence of fungicide-resistant biotypes. Thus, a supply of new strobilurin fungicides is highly valuable. In this study, a series of novel methoxyacrylate analogs containing a cyano-substituted hydrazine moiety as the side chain was synthesized and evaluated for their anti-plant pathogenic activities. Compounds 2-04, 2-05, 2-07 and 2-14 exhibited a relatively broad range of fungicidal activity. Compounds 2-04, 2-13 and 2-14 exhibited good fungicidal activity against Sclerotinia sclerotiorum with median effective concentrations (EC50 ) of 3.84, 3.50 and 3.80 μg mL-1 , respectively. Most of these compounds showed excellent inhibition of spore germination in Magnaporthe grisea at 25 μg mL-1 . Moreover, in an in vivo test, compounds 2-02, 2-04, 2-07 and 2-13 exhibited potent fungicidal activities against the tested plant diseases at 400 μg mL-1 . Notably, compound 2-07 showed comparable or better activity than the commercially positive controls, azoxystrobin and procloraz, against powdery mildew of cucumber and rice blast fungus in the field trails at the same application dosages. This study indicated that methoxyacrylate analogs containing a cyano-substituted hydrazone side chain can serve as potential fungicidal candidates for crop protection. © 2019 Society of Chemical Industry.

Application of intelligent spore capture system in prediction of cucumber downy mildew and cucumber powdery mildew

In order to explore the application of the new integrated intelligent spore capture system developed in China in the prediction of cucumber downy mildew and cucumber powdery mildew, the main working parameters of the integrated intelligent spore capture system, such as the presence or absence of air cutting head, the height of air collection port and the time of air collection, were optimized by identifying the morphology of captured spores in the case of natural disease in the field. The relationship between the disease index of cucumber downy mildew and cucumber powdery mildew in greenhouse and the amount of spores captured was analyzed through the dynamic monitoring of disease and spores. The results show that when the air cutting head is not installed, the height of the air collection port is 70 cm, and the period of 10: 00–10: 30 was beneficial to the capture of spores. The disease index of cucumber downy mildew and cucumber powdery mildew had a strong positive correlation with the total amount of spores captured for 7 consecutive days. Continuous monitoring of cucumber downy mildew sporangia and rapid increase in the number is a predictor of the occurrence or rapid increase of cucumber downy mildew. The conidia of cucumber powdery mildew were not detected before the disease onset, and the number of conidia captured was still small at the peak of the disease. The research shows that the integrated intelligent spore capture system is suitable for the prediction of cucumber downy mildew, but there are still some problems in the prediction of cucumber powdery mildew.

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Deep Learning-Based Segmentation and Quantification of Cucumber Powdery Mildew Using Convolutional Neural Network.

Powdery mildew is a common disease in plants, and it is also one of the main diseases in the middle and final stages of cucumber (Cucumis sativus). Powdery mildew on plant leaves affects the photosynthesis, which may reduce the plant yield. Therefore, it is of great significance to automatically identify powdery mildew. Currently, most image-based models commonly regard the powdery mildew identification problem as a dichotomy case, yielding a true or false classification assertion. However, quantitative assessment of disease resistance traits plays an important role in the screening of breeders for plant varieties. Therefore, there is an urgent need to exploit the extent to which leaves are infected which can be obtained by the area of diseases regions. In order to tackle these challenges, we propose a semantic segmentation model based on convolutional neural networks (CNN) to segment the powdery mildew on cucumber leaf images at pixel level, achieving an average pixel accuracy of 96.08%, intersection over union of 72.11% and Dice accuracy of 83.45% on twenty test samples. This outperforms the existing segmentation methods, K-means, Random forest, and GBDT methods. In conclusion, the proposed model is capable of segmenting the powdery mildew on cucumber leaves at pixel level, which makes a valuable tool for cucumber breeders to assess the severity of powdery mildew.

A three-dimensional threshold algorithm based on histogram reconstruction and dimensionality reduction for registering cucumber powdery mildew

Analysis of plant disease images can increase disease detection accuracy. Successful extraction of lesions can provide a good precondition for research on the feature analysis (texture, color and shape) and detection of occurrence area and severity for cucumber powdery mildew. This paper proposes a new Otsu algorithm based on three-dimensional histogram reconstruction and dimension reduction to segment powdery mildew from cucumber disease images. In total, 166 RGB images of cucumber powdery mildew with 1440 × 1080 pixels were obtained from the greenhouse nos. 1 and 2 using a high-speed dome camera. First, a new correction formula is proposed to correct anomalous points to the correct position (around the line connecting the origin with diagonal end). Second, we reduced the algorithm dimension to save time and spatial complexity and achieved the desired results. Finally, the optimal threshold was obtained by a Gaussian fitting iteration. Convergence analysis demonstrated that the method should be able to obtain a new threshold after each iteration. Experimental results showed an average false negative error rate of 0.10% and average false positive error rate of 1.27%. The average running time was 5.082 s. Taken together, these represent satisfactory results for rapid automatic identification of cucumber powdery mildew.

Management of Cucumber Powdery Mildew Disease Caused by Podosphaera xanthii by some Fungicides and Resistance Inducing Chemicals

Management of Cucumber Powdery Mildew Disease Caused by Podosphaera xanthii by some Fungicides and Resistance Inducing Chemicals

Systemic resistance inducer acibenzolar-S-methyl (ASM) and its microencapsulated formulations: their long-lasting control efficacy against cucumber diseases and mitigation of phytotoxicity.

The development of fungicide resistance by pathogens is a major limiting factor for the control of plant diseases. To combat resistance development, the use of broad-spectrum but nonfungitoxic resistance inducers such as acibenzolar-S-methyl (ASM) is a promising approach because the orchestrated mechanisms underlying systemic acquired resistance induced by ASM are less likely to be overcome easily by pathogens. However, phytotoxicity is the main limiting factor of ASM. ASM was highly active at inducing systemic resistance against powdery and downy mildews, the two major cucumber diseases. Based on the duration of the control, ASM effectiveness against these diseases was maintained well in plastic greenhouses and the number of sprays could be reduced. Control efficacy after seed treatment with ASM and the applications of microencapsulated ASM was also high against mildews in pots as well as in greenhouse experiments, with no problematic phytotoxicity. The use of ASM is a potential integrated pest management-based tactic to control cucumber powdery and downy mildews because its long-lasting efficacy allows the application of typical fungicides to be reduced. The risk for resistance development in mildew pathogens will also be reduced. ASM seed treatment as well as soil amendment with microencapsulated ASM is effective in lowering the risk for the phytotoxicity of this compound. © 2018 Society of Chemical Industry.

Effects of different fractions of Rheum palmatum root extract and anthraquinone compounds on fungicidal, insecticidal, and herbicidal activities

This study was conducted to evaluate the suppression of Pyricularia oryzae, Colletotrichum coccodes, Rhizoctonia solani, Phytophthora capsici, and Botrytis cinerea, as well as the acaricidal activities against the two-spotted spider mite (Tetranychus urticae) and the weed control efficacy of solvent fractions of Pheum palmatum extract. In addition, we determined the inhibitory activities of the main bioactive substances of R. palmatum (aloe-emodin, emodin, chrysophanol, and physcion) against the aforementioned pathogens. The suppression rates of 5% ethylacetate and BuOH fractions against P. oryzae were 70 and 52%, respectively. However, the other fractions including hexane showed very little suppression of P. oryzae. Moreover, C. coccodes, B. cinerea, R. solani, and P. capsici were suppressed by 61, 47, 58, and 91% in response to treatment with the 5% ethylacetate fraction of R. palmatum, respectively, compared with the control. The ethylacetate and BuOH fractions were also confirmed in greenhouse trials of rice seedlings infected by P. oryzae. The ethylacetate and BuOH fractions of R. palmatum ethanol extract were shown to have the potential for control of powdery mildew (Sphaerotheca fuliginea causes) and weeds, but not to have acaricidal activities against the two-spotted spider mite. The suppression rates of P. oryzae and P. capsici increased with increasing concentrations of chrysophanol, emodin, aloe-emodin, and rhein, but these extracts had no effect on cucumber powdery mildew or two-spotted spider mites. The anthraquinone levels in the ethylacetate fraction were much higher than in the BuOH fraction. Thus, the higher suppression of P. oryzae and P. capsici of the ethylacetate fraction observed in this study may be related to higher levels of anthraquinone substances in the ethylacetate fraction than the BuOH fraction.

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Isolation, purification and identification of the active compound of turmeric and its potential application to control cucumber powdery mildew

AbstractCucumber powdery mildew is a destructive foliar disease caused by Podosphaera xanthii (formerly known as Sphaerotheca fuliginea) that substantially damages the yield and quality of crops. The control of this disease primarily involves the use of chemical pesticides that cause serious environmental problems. Currently, numerous studies have indicated that some plant extracts or products potentially have the ability to act as natural pesticides to control plant diseases. It has been reported that turmeric (Curcuma longa L.) and its extract can be used in agriculture due to their insecticidal and fungicidal properties. However, the most effective fungicidal component of this plant is still unknown. In the current study, the crude extract of C. longa L. was found to have a fungicidal effect against P. xanthii. Afterwards, eight fractions (Fr.1–Fr.8) were gradually separated from the crude extract by column chromatography. Fraction 1 had the highest fungicidal effect against this pathogen among the eight fractions. The active compound, (+)-(S)-ar-turmerone, was separated from Fr 1 by semi-preparative high-performance liquid chromatography and identified based on its 1H nuclear magnetic resonance (NMR) and 13C NMR spectrum data. The EC50 value of (+)-(S)-ar-turmerone was found to be 28.7 µg/ml. The compound also proved to have a curative effect. This is the first study to report that the compound (+)-(S)-ar-turmerone has an effect on controlling this disease. These results provide a basis for developing a new phytochemical fungicide from C. longa L. extract.