Anthracnose Development Research Articles

Dry Bean and Anthracnose Development From Seeds With Varying Symptom Severity.

Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum, is a damaging seed-transmitted disease of dry beans that causes reduced seed quality and yield. Seed-to-seedling transmission of C. lindemuthianum has been documented as high as 15% in asymptomatic seeds under greenhouse conditions. Increasing pathogen colonization in seeds has been correlated with increasing anthracnose seed symptoms via quantitative PCR (qPCR), but stem colonization has not been quantified. Previous studies also have characterized seed yield and quality losses caused by planting C. lindemuthianum-infected seeds, but none evaluated the effect of growing asymptomatic seeds on disease and plant development under field conditions. A real-time qPCR assay was developed in this study and used to detect C. lindemuthianum in the stems of seedlings as early as 15 days after planting. Field trials measured the seed-to-seedling transmission of C. lindemuthianum across levels of anthracnose symptoms in seeds ranging from healthy to severely discolored. Results from these two field trials indicated that emergence and yield decreased and foliar symptoms, pathogen detection, and incidence of symptoms on progeny seeds increased as the severity of infection in planted seeds increased. In both years, planting asymptomatic seeds resulted in higher anthracnose severity than planting healthy seeds. Yield, seed weight, and incidence of symptoms on progeny seeds were not higher in asymptomatic seeds than in healthy seeds in 2014, when moderate disease pressure was observed. However, these factors were significantly different in 2015, when anthracnose severity was driven up to 75% by conducive weather conditions. This serves as a strong warning to growers that planting seed grown in a field where anthracnose was present, even if those seeds are asymptomatic, can result in yield and quality losses. Planting certified dry bean seed is always recommended.

Influence of environmental factors on the Development of anthracnose of banana

Influence of environmental factors on the Development of anthracnose of banana

Basil oil incorporated beeswax coating to increase shelf life and reduce anthracnose development in mango cv. Willard

Use of biologically safe, essential oil-incorporated fruit coatings to reduce postharvest losses has become an attractive alternative to synthetic fungicides in recent years. Increase in shelf life due to reduced water loss and reduced evaporation of essential oils (EO) within the coating are key advantages of incorporating EOs to fruit coatings. The effect of beeswax as a fruit coating with and without essential oil on the postharvest quality and natural disease development of mango (cv. Willard) was evaluated by conducting a laboratory experiment. Pure Beeswax, dissolved either in vegetable oil (1:3 w/v) or petroleum ether (1:4 w/v), served as the coating material. Basil oil at 400 or 600 μL L-1 was incorporated to the different coating material. Fruits with no coating and no essential oil served as controls. Eight replicate fruits were used per treatment and three trials were performed. Treated fruits were arranged in a Completely Randomized Design and kept under ambient conditions. Daily observations were made on natural disease development and weight loss. The Total Soluble Solid content and titrable acidity were measured at eating ripe stage and sensory evaluation by a taste panel was also obtained. Data were analyzed using ANOVA with SPSS software version 20.0 package. Results indicated that basil oil in beeswax significantly reduced physiological weight loss, delayed fruit ripening and also delayed and reduced postharvest disease development.

Special aspects of the development of black currant bushes depending on weediness level in the Ukrainian polissia

We studied the weeds species composition in the black currantplantations of Ukrainian Polissia. The species composition of weeds has been analyzedand is was typical for thisarea. Twelve weed species were found during the study; they included annual (89.8%) and perennial ones (10.2%). A number of species were prevalent among the perennial weeds, namely common dandelion (Taraxacum officinaleWigg.) –2.5 pcs/m2, field milk thistle (Sonchus arvensisL.) –2.8 pcs/m2, couch grass (Elytrigia repensL.) –8.8 pcs/m2, and field sorrel (Rumex acetostellaL.) –3.2 pcs/m2. The most common annual species of weeds were lamb’s quarters (Chenopodium albumL.) –44.2 pcs/m2, shepherd’s purse (Capsella bursa-pastorisL.) –36.3 pcs/m2, smooth meadow grass (Poa annuaL.) –25.1 pcs/m2, and Amaranthus retroflexus(Amaranthus retroflexusL.) –19.6 pcs/m2. Throughout the study period, the least common weeds in black currant plantations were chickweed (Stellaria mediaL.) –14.8 pcs/m2, annual nettle (Urtica urensL.) –1.6 pcs/m2, quickweed (Galinsoga parvifloraCav.) –9.1 pcs/m2, and field pansy (Viola arvensisMurr.)–2.6 pcs/m2. We registered that with theweediness of 8-9 points the area of black currant leaves from a bush decreases by 1.9 m2, while the chlorophyll content in the leaves reduced by 20.8mg/100g. On the contrary, the dry matter content inleaves increasedfrom 29 to 61%. Significant negative effect of weeds on the activity of black currant and leads to a decrease in plant tolerance againstthe sucking pests and diseases. Thus, under high and very high weediness (8-9 points),the development of anthracnose (Gioesporium ribisMont.) was 32–48%, powdery mildew (Sphaerotheca mors Uvae.) and septoria blight (Mycosphaerella ribisLind.) were 16 and 15% respectively. We proved that a high weediness level reduces the yield of berriesby 56%in black currant plantations.

Active coatings based on hydroxypropyl methylcellulose and silver nanoparticles to extend the papaya (Carica papaya L.) shelf life

This study aimed to understand the effect of silver nanoparticles (AgNPs) on physiochemical properties of hydroxypropyl methylcellulose (HPMC) film-forming solutions (FFS) and nanocomposite films (NCF), as well as the efficacy of these materials to control the development of anthracnose caused by Colletotrichum gloeosporioides in papaya (Carica papaya L.). FFS were characterized by pH, particle size distribution, and rheology. In addition, thickness, morphology, water contact angle, barrier, chemical, crystallinity, thermal, and mechanical properties from NCF were investigated. The minimum inhibitory concentration of AgNPs against C. gloeosporioides was determined by in vitro test. FFS with 0.25 wt% of AgNPs were used as coatings in papayas inoculated with C. gloeosporioides. Finally, the physicochemical parameters were investigated during their storing up to 7 days at 10 °C, followed by 7 days at 20 °C. The presence of AgNPs impacted the thickness, morphology, moisture content, chemical bonds, crystalline structure, and thermal properties of films. Coatings with 0.25 wt% of AgNPs reduced the incidence and severity of C. gloeosporioides and avoided the weight loss of papayas during storing. The ripening of papaya occurred naturally, showing that the coating only delayed this process. Thus, HPMC-AgNPs coating can be an alternative to extend the papaya shelf life.

Spectral analysis for the early detection of anthracnose in fruits of Sugar Mango (Mangifera indica)

The use of spectroscopy in fruits provides spectral information that can be used to estimate chemical-physiological variables or to determine the phytopathological state of the fruit. Mango is a fruit prone to develop the anthracnose pathogen during its harvest, affecting its commercialization. There are different studies of mango that evaluate the development of anthracnose, however, no work in the previous literature has presented a method to estimate early the state of development of anthracnose. In this work, a spectroradiometer was used to evaluate the evolution of anthracnose in mango fruits. Three stages of development in the mango were analyzed (healthy, asymptomatic and diseased) and the performance was evaluated with random forest (RF) and support vector machines (SVM). The principal component analysis (PCA) and linear discriminant analysis (LDA) were used to reduce the dimensionality and identify the most significant bands of the spectrum used, with the help of a Gaussian filter. A total of 61 significant bands with PCA and 29 significant bands with LDA were found. The best evaluation performance was obtained with LDA reaching an accuracy of 91–100% in the three classes. The bands 399, 514, 726, 822, 912 and 1061 nm of the set of 29 bands of LDA are highlighted to identify asymptomatic fruits. This non-destructive method to identify the development of anthracnose at an early stage could benefit the farmer by helping to improve the commercialization of mango. In general, early detection of anthracnose, which is not visible, reached an average accuracy in the 29 bands identified with 91% LDA.

Modeling for anthracnose development in mango in relation to weather parameters

Mango anthracnose severity on leaves was recorded at 14 day intervals throughout the year 2013, 2014, 2015, 2017 and 2018 on mango cultivar Dashaheri. Logistic model was best for the year 2013, 2014, 2015, 2018 and pooled data of these years had lower mean square error (MSE) 37.67, 91.29, 100.84, 65.80 and 72.32 along with high coefficient of determination (R(Dodd et al. 1991)) 0.753, 0.532, 0.534, 0.656 and 0.606, respectively. Maximum anthracnose development i.e. periodical disease progression (6.9%) was highest from 31st to 33th Standard Meteorological Weeks (SMW) because of cumulative effect of minimum temperature (27 °C) and morning relative humidity (≥ 90%) along with the rainfall (56 mm). Mango anthracnose severity was positively and significantly correlated with the minimum temperature (0.62) followed by rainfall (0.46) on all year pooled data basis, whereas the highest correlation 0.65 was observed for the years 2014 and 2015. The regression model based on pooled data has performed better an alternative regression model of each individual year with the highest adjusted R2 value i.e. 0.747, explaining the effects of minimum temperature, morning relative humidity and rainfall on the anthracnose severity.

Inhibitory effect and possible mechanism of carvacrol against Colletotrichum fructicola

Carvacrol (CVR) is an essential oil and has been reported to exhibit significant inhibitory effects against a wide range of microorganisms. Anthracnose, which is caused by Colletotrichum fructicola is one of the most serious postharvest diseases in pitaya fruit. In this study, we investigate the inhibitory effect of CVR against C. fructicola and elucidate the possible modes of action. The results from our study showed that treatment with CVR could effectively inhibit mycelial growth, spore germination and germ tube elongation of C. fructicola in vitro, significantly reducing the onset and development of anthracnose in red pitaya fruit. Membrane permeability and leakage of cellular components in the hyphae of C. fructicola increased as the concentrations of CVR increased. The results from microscopy indicated that CVR treatment caused abnormalities of hyphal morphology, disruption of cytoplasmic membranes, and disorganization of intracellular organelles. Moreover, CVR treatments induced the generation of reactive oxygen species (ROS), which caused oxidative injury to the cell membrane vialipid peroxidation. The antifungal mechanism of CVR against C. fructicola may be attributed to induced ROS production, increased membrane permeability, abnormalities of ultrastructure, and loss of intracellular contents.

Biological Activity of <i>Syzygium aromaticum</i> and <i>Ravensara aromatica</i> Essential Oils from Madagascar and Their Possible Use against Postharvest Mango Anthracnose

The fungitoxicity of five Malagasy essential oils (Eos) against Colletotrichum asianum was assessed in terms of conidial germination and mycelial growth. Their effect on defense-related compounds content, physicochemical properties and anthracnose lesions in mango fruits was also determined. Four of the tested Eos were from Ravensara aromatica leaves, and the last Eo was extracted from clove leaves. Their chemical compositions were then determined through GC-MS analysis and the active compound of the most fungitoxic Eo was determined by testing the toxicity of its major component to C. asianums spore germination, mycelial growth and its ability to inhibit anthracnose development on mango fruits. The R. aromatica Eos tested were fungistatic to C. asianum, whereas clove Eo was fungitoxic and the 4 chemotypes of R. aromatica Eo exhibited variable inhibiting capabilities: 1) all tested doses of all Eos (112.5 and 225 μL/L of air) were effective against C. asianum mycelial growth (10% - 100% inhibition) but doses of 225 μL/L were more inhibitory than those of 112.5 μL/L, 2) Conidial germination was more resistant to Eos toxicity since only 225 μL/L of methyl eugenol chemotype of R. aromatica Eo, all tested doses of the sabinene chemotype of R. aromatica Eo and clove Eo were found inhibitory toward conidial germination of C. asianum. 30 μL/L of sprayed clove Eoweretested on inoculated mangoes and were found to be effective against anthracnose development without affecting the resorcinol content in mango peel and the physicochemical properties of mango pulp. Tests on the major components of clove Eo showed fungitoxic activities against mycelial growth and conidial germination of C. asianum similar to those of clove Eo.

KAJIAN JENIS FUNGISIDA DAN INTERVAL APLIKASI TERHADAP PERKEMBANGAN PENYAKIT ANTRAKNOSA PADA KEDELAI

Soybean is an important commodity after rice and corn. The attack of plant pest organisms in cultivation decreased soybean productivity. Anthracnose is a disease that can reduce soybean production to 95%. The use of excessive synthetic chemical fungicides causes resistance to plant disturbing organisms and leaves chemical residues. The solution to overcome this problem is pay attention using types of fungicide active ingredients and span application time. This study aims to determine the effect of several types of fungicides and span application time on the development of anthracnose and yields. This research was carried out from February to April 2018 on Agroteknopark Jubung land of Jember University. This study used a Factorial Randomized Group Design model with 9 combinations of treatments and 4 replications. The first factor of the type of fungicide consisted of three levels, namely Triadimefon, T. harzianum and betel leaf. The second factor is the span application time of 3.5 and 7 days. The research data were analyzed using variance analysis, if there were significant differences Duncan's Multiple Range Test (DMRT) test was carried out at the level of 5%. Observation parameters included the disease incidence, diseases severity, rate of infection, and weight of pods. The results of the study showed that the combination treatment of PT3 (vegetable fungicide with betel leaves with span application time of 7 days) was the most efficient than the other treatments and gave the results of the rate of disease infection (0.84 units per day).Keywords: anthracnose, fungicide, infection rate, soybeans

Functional analysis of CfSnf1 in the development and pathogenicity of anthracnose fungus Colletotrichum fructicola on tea-oil tree

BackgroundTea-oil tree (Camellia oleifera) is a unique edible-oil tree in China, and anthracnose occurs in wherever it is cultivated, causing great economic losses each year. We have previously identified the Ascomycete fungus Colletotrichum fructicola as the major pathogen of anthracnose in Ca.oleifera. The purpose of this study was to characterize the biological function of Snf1 protein, a key component of the AMPK (AMP-activated protein kinase) pathway, for the molecular pathogenic-mechanisms of C. fructicola.ResultsWe characterized CfSnf1 as the homolog of Saccharomyces cerevisiae Snf1. Targeted CfSNF1 gene deletion revealed that CfSnf1 is involved in the utilization of specific carbon sources, conidiation, and stress responses. We further found that the ΔCfSnf1 mutant was not pathogenic to Ca.oleifera, resulting from its defect in appressorium formation. In addition, we provided evidence showing crosstalk between the AMPK and the cAMP/PKA pathways for the first time in filamentous fungi.ConclusionThis study indicate that CfSnf1 is a critical factor in the development and pathogenicity of C. fructicola and, therefore, a potential fungicide target for anthracnose control.

Potassium silicate treatment enhances natural disease resistance in <i>Capsicum annuum</i> L. and reduces anthracnose disease development

The study investigated the possibility of enhancing natural disease resistance (NDR) of chili (Capsicum annuum L.), cvs. HYW and CA8, against anthracnose disease, using potassium silicate (Kasil®) as a soil drench or postharvest spray treatment. Anthracnose disease in chili, in this study, was shown to be caused by Colletotrichum acutatum. Potassium silicate (Kasil®), applied as a postharvest spray to the fruit of either cultivar, at 100, 200 and 400 mg/l, reduced anthracnose development significantly (p = 0.05) when the fruits were challenge-inoculated 3 days after treatment. Treatment was slightly more effective at 200 mg/l. There was 100% of reduction of anthracnose in treated fruits of cv. CA-8 throughout an 8th day period of storage following fruit inoculation. In the cv. HYW, the same treatment showed 100% disease reduction only initially, 4 days after inoculation. The treatment was also applied as a pre-harvest soil drench commencing from flower initiation, at 200 mg/l, weekly for 4 weeks. The treatment reduced anthracnose disease significantly (p = 0.05) in harvested fruits, challenge-inoculated with C. acutatum. Spore germination assay revealed that potassium silicate had no antifungal effect to C. acutatum. Potassium silicate (Kasil®)-treated fruits, inoculated with C. acutatum after harvest, showed greater accumulation of phytoalexins and increased level of β-1, 3-glucanase in fruit tissue.

Interaction between Bean and Colletotrichum gloeosporioides: Understanding Through a Biochemical Approach.

In addition to its role in animals, nowadays nitric oxide (NO) is considered as an emerging signaling molecule in plant systems. It is now believed that NO exerts its pivotal role in various plant physiological processes, such as in seed germination, plant developmental stages, and plant defense mechanisms. In this study, we have taken an initiative to show the biochemical basis of defense response activation in bean leaves during the progression of Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. in detached bean leaves. Stages of pathogen penetration and colonization were successfully established in the detached bean leaves. Results showed up-regulation of different defense-related enzymes and other defense molecules, such as phenols, flavonoids, callose, and lignin molecules, along with NO at early stages of pathogen invasion. Although in the later stages of the disease, development of NO and other defense components (excluding lignin) were down-regulated, the production of reactive oxygen species in the form of H2O2 became elevated. Consequently, other stress markers, such as lipid peroxidation, proline content, and chlorophyll content, were changed accordingly. Correlation between the disease index and other defense molecules, along with NO, indicate that production of NO and reactive oxygen species (ROS) might influence the development of anthracnose in common bean.

Potential use of thymol to control anthracnose development in mango

Anthracnose is the main postharvest disease that affects mango production on Reunion Island. It is caused by a pathogenic fungus called Colletotrichum gloeosporioides. Fruit produced for the export market are always treated with chemicals such as fludioxonil, benomyl and prochloraz. This type of postharvest treatment is not in line with consumer expectations, as consumers prefer fruits treated with nonharmful and natural products. The objective of this work was to study alternative postharvest treatments using the fungitoxic properties of thymol, a natural molecule synthesized by thyme (Thymus vulgaris L. thymoliferum). Thymol, prepared in a terpene solvent that acts as a penetrating agent, was effective on quiescent and wound mango anthracnose. When diluted to a final concentration of 0.1%, no necrosis development due to pathogens during storage was observed on fruits. The thymol-based treatment also made it possible to stimulate some of the metabolic pathways involved in the resistance of the fruit to the development of Colletotrichum gloeosporioides, particularly the stimulation of gallic acid biosynthesis. However, the treatment significantly affected fruit maturation and quality, especially the peel colour and sugar content. Additional studies must be carried out to determine the optimal thymol concentration for controlling storage disease without impacting fruit quality.

Colletotrichum Species Associated with Japanese Plum (Prunus salicina) Anthracnose in South Korea

A total of 24 Colletotrichum isolates were isolated from diseased Japanese plum (Prunus salicina) fruits showing chlorotic regions with whitish-brown sunken necrotic lesions and phylogenetic relationships among the collected Colletotrichum isolates were determined. A subset of 11 isolates was chosen for further taxonomic study based on morphology and molecular characteristics identified using the internal transcribed spacer (ITS) and beta-tubulin (TUB2) genes. Isolates in the C. acutatum complex were analyzed using partial sequencing of five gene regions (ITS, GAPDH, ACT, TUB2, and CHS), and C. gloeosporioides sensu lato (s.l.) isolates were analyzed using seven gene regions (ITS, TUB2, GAPDH, ACT, CAL, CHS-1, and ApMat). Morphological assessments in combination with phylogenetic analysis delineated four species of Colletotrichum including C. gloeosporioides sensu stricto (s.s.), C. nymphaeae, C. foriniae, and C. siamense; these data identify Colletotrichum fioriniae and C. siamense two new species associated with plum anthracnose in South Korea. Finally, the pathogenicity of these four species in the development of plum anthracnose in South Korea was confirmed by inoculations of plum fruit.

Bacillus sp. strain M10 as a potential biocontrol agent protecting chili pepper and tomato fruits from anthracnose disease caused by Colletotrichum capsici

Bacillus sp. strain M10 was observed to produce an antifungal protein that inhibits the growth of Colletotrichum capsici, which is the causal agent of anthracnose disease of chili pepper and tomato. Ammonium sulfate precipitation, anion exchange chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the protein was approximately 55.4 kDa. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis and a subsequent sequence database search indicated the antifungal protein was most similar to the Bacillus amyloliquefaciens vegetative catalase (KatA) protein. Light microscopy observation revealed that the antifungal protein induced abnormal hyphal elongation and conidial swelling and rupture. The protein considerably inhibited anthracnose development and protected the fruits from C. capsici infection. Thus, Bacillus sp. strain M10 and/or its putative catalase may be useful as a post-harvest biocontrol agent that protects chili pepper and tomato fruits from anthracnose disease caused by C. capsici.

Development of PSP1, a Biostimulant Based on the Elicitor AsES for Disease Management in Monocot and Dicot Crops.

In this work, we present a novel biostimulant for sustainable crop disease management, PSP1, based on the plant defense-elicitor AsES, an extracellular protease produced by the strawberry fungal pathogen Acremonium strictum. Fungal fermentation conditions and downstream processing were determined to maximize extracellular protein production, product stability and a high plant defense-eliciting activity, as monitored by anthracnose resistance in supernatant-treated strawberry plants subsequently infected with a virulent strain of Colletotrichum acutatum. Fermentation batches were shown to reduce anthracnose development by 30–60% as compared to infected non-treated plants. Product formulation was shown to be stable for 6 months when stored at temperatures up to 45°C and toxicological tests showed that PSP1 was harmless to beneficial organisms and non-toxic to mammalian species at concentrations 50 times higher than those used in plant experiments. Furthermore, disease protection studies using dilutions of PSP1 indicated that there is a minimum threshold protease activity needed to induce pathogen defense in strawberry and that this induction effect is dose-independent. A significant characteristic of PSP1 is its broad-range protection against different diseases in various crop species. In soybean, PSP1 reduced the symptomatology by 70% of Corynespora cassiicola, etiological agent of the target spot. This protection effect was similar to the commercial inducer BION 500 WG based on BTH, and both products were shown to induce an oxidative burst and up-regulated PR1-gene expression in soybean. Furthermore, a double PSP1-treatment on greenhouse-grown sugarcane plants provided protection against bacterial red stripe disease caused by Acidovorax avenae and a double foliar application of PSP1 on field-grown wheat plants significantly increased resistance against Fusarium graminearum, causal agent of head blight disease, manifested mainly in an increased seed germination rate. In summary, these disease protection studies demonstrated an effective control against both bacterial and fungal pathogens in both monocot and dicot crop species, which together with its low production cost, effectiveness at low concentrations, long shelf-life, tolerance to high temperatures, harmlessness to non-target organisms and simple handling and application, make PSP1 a very promising candidate for effective and sustainable disease management in many crop species.

Postharvest treatment of mango: Potential use of essential oil with thymol to control anthracnose development

Introduction – Anthracnose, a fungal disease caused by the Colletotrichum gloeosporioides species is the main postharvest problem concerning mango (Mangifera indica) production on La Reunion Island. Traditional postharvest treatments involve chemical compounds that do not comply with the expectations of consumers or importing countries. Chemical treatments are generally used against C. gloeosporioides. Our goal was to develop alternative postharvest treatments using the fungitoxic properties of two essential oils (EO). Materials and methods – Two commercial essential oils, X2 and X5, were used at various concentrations and compared to a no-oil control. A first batch of treatments were tested in vitro for studying mycelial growth and the inhibition of conidial germination. The second experiment measured the effects of the treatments on the fruit quality of inoculated mangoes var. Tommy Atkins with a solution of C. gloeosporioides spores. Results and discussion – In vitro, X5 mainly composed of thymol was very fungitoxic against C. gloeosporioides. The concentrations of phenolic compounds and resorcinol in the fruits were increased after the X5 treatments, expressing some positive effects of essential oil treatments on fruit resistance mechanisms. The quality of treated fruits verified the requirements to meet consumers' expectations. Conclusion – Thymol-based EO exhibited a strong fungitoxic in vitro activity but it had no detectable effect when applied by volatilization on mango necrosis. Alternatives ways of treatments should be tested.

Use of Plant Water Extracts and Bio-Control Agents for Post-Harvest Management of Mango Anthracnose Caused by Colletotrichum Gloeosporioides

Mango anthracnose caused by Colletotrichum gloeosporioides Penz. with its perfect stage as Glomerella cingulata is one of the most important and serious disease in all the mango growing regions of India including Himachal Pradesh. It causes 40 to 50 per cent post-harvest losses that sometimes increased up to 100 per cent under wet or very humid conditions. Efficacy of plant water extract and bio-control agents was tested against development of anthracnose on mango fruit cv. Dashehari. Fruit dip in leaf water extract of Azadiracta indica (15%) and solution of Trichoderma harzianum (1.2x104cfu/ml) for five minutes was found most effective and controlled the disease upto 70 to 80 per cent.

Control of anthracnose caused by Colletotrichum species in guava, mango and papaya using synergistic combinations of chitosan and Cymbopogon citratus (D.C. ex Nees) Stapf. essential oil

This study assessed the efficacy of chitosan (Chi) and Cymbopogon citratus (D.C. ex Nees) Stapf. essential oil (CCEO) combinations to control the mycelial growth of five pathogenic Colletotrichum species (C. asianum, C. siamense, C. fructicola, C. tropicale and C. karstii) in vitro, as well as the anthracnose development in guava (Psidium guajava L.) cv. Paluma, mango (Mangifera indica L.) cv. Tommy Atkins and papaya (Carica papaya L.) cv. Papaya artificially inoculated with these species. Combinations of Chi (2.5, 5 or 7.5mg/mL) and CCEO (0.15, 0.3, 0.6 or 1.25μL/mL) inhibited the mycelial growth of all tested fungal species in vitro. Examined Chi-CCEO combinations showed additive or synergistic interactions to inhibit the target Colletotrichum species based on the Abbott index. Coatings formed by synergistic Chi (5mg/mL) and CCEO (0.15, 0.3 or 0.6μL/mL) combinations decreased anthracnose lesion development in guava, mango and papaya inoculated with any of the tested Colleotrichum species during storage. Overall, anthracnose lesion development inhibition in fruit coated with synergistic Chi-CCEO combinations was higher than that observed in fruit treated with synthetic fungicides. These results show that the application of coatings formed by Chi-CCEO synergistic combinations could be effective to control postharvest anthracnose development in fruit.