Gray Mold Infection Research Articles

Combining an antagonistic yeast with harpin treatment to control postharvest decay of kiwifruit

Integrated management, utilizing different non-chemical methods, is an approach to controlling postharvest losses that is being actively investigated. In the present study, the use of an antagonistic yeast, Candida diversa, combined with harpin (a hypersensitive response elicitor) treatment was evaluated for their ability to prevent infection of kiwifruit after they were artificially inoculated with Botrytis cinerea or Penicillium expansum. Natural infection of treated fruit was also assessed. As a standalone treatment, C. diversa or harpin significantly reduced gray (B. cinerea) and blue mold (P. expansum) infections on kiwifruit, relative to the untreated control fruit, and also reduced the level of natural infection. The combination of C. diversa and harpin treatment, however, provided a superior level of control on fruit, relative to either treatment alone. Harpin did not negatively impact C. diversa growth in kiwifruit wounds. Treatment of kiwifruit with C. diversa and harpin alone or in combination also induced the activity of enzymes involved in defense response, such as polyphenol oxidase, peroxidase and superoxide dismutase. Harpin alone or in combination with C. diversa enhanced accumulation of lignin content in kiwifruit as well. The mode of action by which harpin enhanced biocontrol efficacy of C. diversa may be partially attributed to the elicitation of defense response in kiwifruit. Integrating the use of antagonistic yeast with harpin treatment has potential as an effective method for the control of postharvest decay in kiwifruit.

Effect of Thymol and Linalool Fumigation on Postharvest Diseases of Table Grapes

Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0°C. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 μg/mL) and linalool (120 μg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 μg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 μg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 μg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage.

Botryticidal Activity of Nanosized Silver‐Chitosan Composite and Its Application for the Control of Gray Mold in Strawberry

Botrytis cinerea Pers, the gray mold fungus, is among the most dangerous plant pathogens that cause great losses in agricultural crops. The botryticidal activities of nanosized silver (nano Ag), fungal chitosan (CTS) irradiated fungal chitosan (IrCTS), and nano Ag-IrCTS composite were investigated. All of the examined materials exhibited powerful antifungal activity against B. cinerea. The most effective compound was nano Ag-IrCTS composite with a minimal inhibitory concentration of 125 μg/mL. The microscopic examination, of treated B. cinerea with the composite, revealed that an obvious alteration in mycelial shape was appeared accompanied and moderate lysis in fungal hyphae. With the prolongation of treatment, most of the fungal mycelia were lysed into small and elastic fragments. The consequence of strawberries coating, with antifungal composite based solution, was the disappearance of gray mold infection signs in 90% of the contaminated fruits after 7 d of storage, treated fruits had a fresh-like appearance at the end of storage. Coating with nano Ag-IrCTS solution could be highly recommended regarding its efficiency in prohibiting B. cinerea growth, preventing gray mold decay and enhancing the overall quality of coated strawberry fruits.

Extending the Shelf Life of Victoria Table Grapes by High Permeability and Fungicide Packaging at Room Temperature

Grapes are one of the most delicious fruits in the world, but normally, they only have a short shelf life at room temperature, a result of their susceptibility to body water loss and grey mould infection. In this study, we developed an active packaging film (APF), which has a sandwich structure with outer and inner layers made of zeolite‐modified low‐density polyethylene (LDPE) with fungicide additives between the two layers. The APF has high permeability for oxygen and is capable of continuously releasing low‐concentration sulfur dioxide over 48 days. The grape storage experiments showed that the shelf life of Victoria table grapes packaged in these APF‐made bags at room temperature was extended to 18 days, compared with 14 days for conventional LDPE packaging and 10 days for unpackaged grapes. At 18 days' storage in APF packaging bags, water loss, berry shatter and berry decay were less than 0.5%, 3% and 5%, respectively, whereas the total soluble solid content and firmness changed only slightly. Copyright © 2012 John Wiley & Sons, Ltd.

EFFECT OF POSTHARVEST PUTRESCINE APPLICATION AND CHITOSAN COATING ON MAINTAINING QUALITY OF TABLE GRAPE CV. “SHAHROUDI” DURING LONG-TERM STORAGE

The role of postharvest application of putrescine (PUT) alone or in combination with chitosan (CH) on maintaining quality of fresh table grapes (Vitis vinifera) cultivar “Shahroudi” was investigated. The clusters were dipped in an aqueous solution containing different concentrations of PUT (0, 1 and 2 mM). Following PUT treatments, some fruits were coated with 1% w/v CH. After treatment, fruits were stored at 0 ± 1C and 90 ± 5% relative humidity for 60 days and 5 additional days in evaluation room. The general appearance of rachis and berries and some physiological characters were estimated. The combination of 1 mM PUT and 1% CH reduced the weight loss, decay incidence, browning, and berry shattering and cracking. Postharvest PUT-treated berries (1 and 2 mM) exhibited higher total phenolic content, catechin, total quercetin and antioxidant activity and the lower quercetin 3-galactoside as compared with other treatments. PRACTICAL APPLICATIONS Table grape is a nonclimacteric fruit with a low physiological activity, but is subject to serious physiological disorders, water loss and fungal deterioration during postharvest handling. Stem browning and gray mold infection caused by the fungus Botrytis cinerea are the two main factors which reduce table grape postharvest quality. Recently, biologically active natural products have started to become an effective alternative to synthetic fungicides in maintaining fruit quality during storage. Chitosan coating has been reported to enhance disease resistance against many fungal diseases, when applied as either a preharvest or postharvest treatment. Polyamines (PAs) are also biological compounds with low molecular weight that are ubiquitous in living organisms. PAs have been reported as anti-senescence agents, the main effects in fruits being retarded color changes, increased fruit firmness, delayed ethylene and respiration rate emissions, induced mechanical resistance.

Postharvest Fruit Rots of Apple in Greece: Pathogen Incidence and Relationships Between Fruit Quality Parameters, Cultivar Susceptibility, and Patulin Production

The incidence of pathogens associated with postharvest fruit rots on the four most extensively cultivated apple cultivars (Red Delicious, Golden Delicious, Granny Smith, and Fuji) in Greece was surveyed during two consecutive storage periods (2008-09 and 2009-10) in five packinghouses located in northern Greece. The fungi isolated were identified based on their morphological characteristics and internal transcribed spacer gene sequencing. In the four cultivars sampled, Penicillium expansum and Botrytis cinerea were the predominant pathogens, accounting for averages of 44.2 and 23.6%, respectively, of the pathogens isolated from the sampled fruit. Two other important rot pathogens were Alternaria tenuissima and Mucor pyriformis, accounting for 16.1 and 6.6%, respectively, of the diseased apple fruit. Other pathogens such as Monilinia laxa, M. fructigena, Botryosphaeria obtusa, Geotrichum candidum, Fusarium avenaceum, and F. proliferatum were isolated at low frequencies and are considered of minor importance. Measurements of the resistance level of the four apple cultivars to fruit rot caused by P. expansum and Botrytis cinerea revealed that Golden Delicious was the most susceptible to blue mold while Fuji was the most susceptible to gray mold infections. Susceptibility to gray mold was negatively correlated with flavonoid and phenol concentration as well to fruit antioxidant activity, while susceptibility to blue mold was negatively correlated with fruit firmness and phenol concentration. Patulin production was significantly higher in Red Delicious and Golden Delicious fruit than in Granny Smith and Fuji fruit and was negatively correlated with the acidity of the fruit. The high incidence of P. expansum and A. tenuissima along with the presence of F. avenaceum and F. proliferatum, all of which are potentially mycotoxin producers, emphasize the risk for mycotoxin contamination of apple fruit juices and by-products. Furthermore, information on the distribution of the pathogens on the main cultivars may be useful for the implementation of strategies to control the diseases and minimize the threat of mycotoxin contamination on each cultivar.

Gray Mold Infection of Actinidia arguta in Italy.

Gray mold is caused by Botrytis cinerea Pers.:Fr., a cosmopolitan and polyphagous fungus that is responsible for significant losses on several fruit crops, including kiwifruit (Actinidia deliciosa), in the field and during storage (2). A. arguta, the hardy kiwifruit, is grown in several countries (e.g., Japan, China, Korea, Russia, and the United States) (1,3) and regions of Italy (Apulia [southeastern], Basilicata [southern], Marche [central eastern], Tuscany [central western], and Piedmont, Friuli Venezia Giulia, and Trentino Alto Adige [northern]) (4). The oblong- to oval-shaped fruit is produced in clusters, has a smooth, edible, thin skin, bears tips with a persistent style, and weighs approximately 5 to 15 g (1,3,4). Several fruits of cv. Ananasnaya selection 'Anna red' harvested from September to October in 2007 and 2008 in the Apulia and Marche regions showed browning and depressions in the surface and a decay of the flesh. Disease affected approximately 5% of 420 examined fruits; symptoms mainly developed in the equatorial zone, eventually expanding through the entire fruit. Severely infected fruit showed deformation followed by drying. In the field or after storage in an environment with high relative humidity, fungal mycelia with sporulation appeared on the surface of the symptomatic areas of the fruit. Nineteen symptomatic fruit were surface disinfested by immersion in a 0.5% sodium hypochlorite solution for 2 min, then rinsed in sterile distilled water. Portions of the flesh were plated onto petri dishes containing potato dextrose agar (PDA) supplemented with 250 mg/liter of each ampicillin and streptomycin sulfate. Colonies that originated from symptomatic portions of the fruit were transferred to new PDA plates and identified as B. cinerea by the morphological features of conidiophores and conidia. Conidia were produced on dichotomously branched conidiophores, which had globose basal cells from mycelia. The conidia were hyaline or pigmented, ellipsoid-obovoid, globoid, and without septa (2). Conidia were collected from an isolate (Accession No. CBS 125087) of B. cinerea recovered from diseased A. arguta fruit grown in Monopoli (BA), Apulia in September 2007, and maintained in pure culture on PDA. A spore suspension was created by flooding plates with a small volume of sterile distilled water plus surfactant (0.05% Triton X-100). The suspension was filtered through four layers of cheesecloth and diluted with sterile water to an absorbance of 0.25 at 425 nm as determined by a spectrophotometer. This suspension contained approximately 1.0 × 106 conidia/ml and was diluted with sterile water to 1 × 104 spores/ml. Twenty microliter droplets of spore suspension were deposited within the equatorial zone on each of 10 nonwounded fruits of cv. Ananasnaya selection 'Anna red'. All fruit developed typical gray mold symptoms after 4 to 5 days of incubation at 20 ± 2°C and 95 to 98% relative humidity. Reisolation from the decayed tissues on PDA produced pure colonies of B. cinerea. To our knowledge, this is the first report of B. cinerea infection on A. arguta in Italy.

MICROBIOLOGICAL QUALITY OF ORGANIC STRAWBERRY FRUIT

The effect of different irrigation methods, mulches and alternative preparations for grey mould control in organic strawberry production was investigated in Jokioinen, Mikkeli and Ruukki, Finland. In the irrigation trial, grey mould infection of fruit was studied from petals and receptacles from early to late flowering. Rainy periods during the flowering season could be seen in the Botrytis cinerea infection of flowers, but on fruit, dry harvest periods kept visible infection low. As a whole, microbial contamination of fruit was more affected by weather conditions than irrigation practice. Organic mulches of green mass, buckwheat husks, straw, birch woodchips, pine woodchips and flax fibre mat were compared with black plastic. Only green mass increased fungal infections on fruit and shortened shelf-life. Biological sprays Trichoderma (Binab ® TF-WP) and Gliocladium (Prestop), compost and garlic extracts as well as seaweed and silicon solution used for grey mould control did not affect fruit quality. In marketable fruit, fungi such as Cladosporium, Acremonium, Penicillium, Trichoderma, Fusarium, Mucor and Alternaria species were abundant while Hainesia lythri and Zythia fragariae (Gnomonia comari ) were uncommon. Infection of Escherichia coli in fruit was investigated on VRB plates, but E. coli was not detected in the fruit.

Biological indicators to estimate the prevalence of gray mold and hairline cracks on table grapes cv. Thompson Seedless after cold storage

Gray mold caused by Botrytis cinerea and hairline cracks are the major cold storage deterioration problems of table grapes ( Vitis vinifera). Currently, table grapes are treated with sulfur dioxide (SO 2), but this treatment does not sufficiently and consistently control B. cinerea. This is probably associated with latent infections that are poorly controlled with SO 2, and to the increased berry propensity to develop hairline cracks following SO 2 treatment. Therefore, the objective of this work was to obtain an early biological indicator to segregate grape lots at harvest to later develop according to the potential gray mold and hairline cracks. In this study, it was possible to distinguish gray mold infections at the stylar end, cheek, and base of the berries. However, on commercial SO 2-treated lots of ‘Thompson Seedless’ table grapes, the occurrence of gray mold after cold storage was best predicted ( Y = 0.45 X, R 2 = 0.84, P < 0.001) by the number of gray mold infections that developed at the base of the berry of surface-disinfected (100 μL L −1 SO 2 for 1 h) grapes that were incubated at harvest in humid chambers (100% relative humidity) for 2 d at 0 °C then 5 d at 20 °C. Similarly, the occurrence of hairline cracks after cold storage was best predicted ( Y = 1.48 + 0.51 X, R 2 = 0.66, P = 0.0002) by the number of hairline cracks induced at harvest by dipping berries in 0.1 mol L −1 citric acid, pH 2, for 3 h at 20 °C, and stained with 0.1 mol L −1 methylene blue for 30 s at 20 °C. At harvest, cuticle content and porosity also predicted the occurrence of hairline cracks after cold storage. However, the cuticle content at harvest did not significantly predict gray mold occurrence at the berry base after cold storage. The occurrence of gray mold in commercial SO 2-treated lots after cold storage was predicted by the prevalence of gray mold at the berry base at harvest. Similarly, the occurrence of hairline cracks after cold storage was predicted by the ability to induce hairline cracks at harvest by acidic pH. Further refinement in this research is needed before using these biological indicators to segregate table grape lots commercially.

Biocontrol of Botrytis cinerea in apple fruit by Cryptococcus laurentii and indole-3-acetic acid

This study evaluated the effect of a yeast antagonist Cryptococcus laurentii and a plant regulator indole-3-acetic acid (IAA) on inhibition of Botrytis cinerea infection in harvested apple fruit. The results showed that the combined treatment with C. laurentii and IAA at 20 μg/ml was a more effective approach to reduce the gray mold rot in apple wounds than the C. laurentii alone. After 4 days of incubation, gray mold incidence in the combined treatment with C. laurentii and IAA was about 18%, which was a 50% reduction in incidence compared to the treatment with C. laurentii alone. Although IAA had no direct antifungal activity against B. cinerea infection when the time interval between IAA treatment and pathogen inoculation was within 2 h, application of IAA strongly reduced gray mold infection when IAA was applied 24 h prior to inoculation with B. cinerea in apple fruit wounds. Moreover, combination of IAA and C. laurentii stimulated the activities of superoxide dismutase, catalase and peroxidase with above 1.5-fold higher than that treatment with C. laurentii alone at 48 h. Therefore, combination of C. laurentii with IAA, which integrated the dual biological activity from the antagonistic yeast and plant regulator, might be developed to be a useful approach to control gray mold in harvested apple fruit.

Early detection of nutrient and biotic stress in Phaseolus vulgaris

Prerequisites for optimal, high crop yield are disease‐free growth and an equilibrated supply of nutrients. Early signatures of stress‐altered physiology, before appearance of symptoms in the visible spectrum, allow timely treatment. Early detection of stress development was carried out on phaseolus vulgaris bean infected with the agriculturally important grey mould pathogen and under conditions of magnesium deficiency, limiting photosynthesis. During stress development, bean plants were monitored by time‐lapse imaging with thermal, video and chlorophyll fluorescence cameras, mounted on a gantry robot system. For early detection of grey mould infection, chlorophyll fluorescence imaging proved to be the most sensitive. This technique detected magnesium deficiency at least three days before visual symptoms appeared. Further development of non‐contact technology for plant health monitoring will help to achieve optimal productivity in greenhouse and field cultures. Associated establishment of a stress catalogue based on early symptoms will allow swift diagnosis.

Indole-3-acetic acid enhances the biocontrol ofPenicillium expansumandBotrytis cinereaon pear fruit byCryptococcus laurentii

This study evaluated the efficacy of indole-3-acetic acid (IAA) alone or with a biocontrol yeast, Cryptococcus laurentii, in the inhibition of blue and gray mold diseases (Penicillium expansum and Botrytis cinerea) on pear fruit. The results demonstrated that a combination of C. laurentii with IAA at 100 microg mL(-1) was more effective in suppressing blue and gray mold infections on pear fruit than application of C. laurentii alone. IAA alone or with C. laurentii stimulated catalase, peroxidase and polyphenol oxidase activities of pear fruit, indicating that IAA can induce fruit-mediated resistance, although this agent alone had no direct antifungal activity.

Changing green leaf volatile biosynthesis in plants: an approach for improving plant resistance against both herbivores and pathogens.

Green leaf volatiles (GLVs) are commonly emitted by green plants, and their production is drastically enhanced when they are under biotic stress. To clarify the ecological function of naturally emitted GLVs, we studied the response of Arabidopsis, whose GLV biosynthesis had been modified, when subjected to herbivory or a pathogenic infection. There was a significant increase in GLV production after herbivory by cabbage white butterfly larvae and pathogen (gray mold) infection in hydroperoxide lyase (HPL) sense Arabidopsis compared with WT controls. The HPL sense modification resulted in the plant being more attractive to the parasitic wasp Cotesia glomerata, leading to higher mortality of the herbivores. The HPL sense modification also resulted in greater inhibition of growth of the fungus. By contrast, HPL antisense Arabidopsis produced fewer GLVs, attracted fewer parasitoids, and was more susceptible to the pathogens than the WT control. These data show that (i) one of the ecological functions of GLV biosynthesis related to resistance against both herbivores and pathogens, and (ii) the genetic modification of GLV biosynthesis could be a unique approach for improving plant resistance against such biotic stresses.

Conjugated polyamines and hydroxycinnamic acids in grape berries during Botrytis cinerea disease development: differences between ‘noble rot’ and ‘grey mould’

ata are provided on contrasting levels of different categories of polyamines and hydroxycinnamic acids during the course of disease development due to Botrytis cinerea on ripe grape berries that led to either noble rot or to grey mould. Noble rot development was mainly characterised by a greater accumulation of wall-bound polyamines at the beginning of infection, whereas the disease process that led to grey mould was marked by an increase of conjugated polyamines. During grey mould infection, coumaric acid was the predominant hydroxycinnamic acid present in both healthy and infected grape berries regardless of infection stage, whereas ferulic acid was present at lower concentrations than the other hydroxycinnamic acids identified. Moreover, changes in the relative proportions of each of the three hydroxycinnamic acids considered showed contrasting patterns according to the sort of rot which developed. The different roles of these compounds (hydroxycinnamic acids and polyamines) and their involvement in the interaction between Botrytis cinerea and grapevines is discussed. During development of grey mould, coumaric acid was the predominant hydroxycinnamic acid at the beginning and the end of infection, whereas caffeic acid predominated during mid stage.

Management of powdery mildew and gray mold of cucumber by Trichoderma harzianum T39 and Ampelomyces quisqualis AQ10

Two biocontrol preparations were tested for their ability to control Sphaerotheca fusca and Botrytis cinerea on greenhouse cucumber. Trichoderma harzianum T39 (TRICHODEX) spray reduced powdery mildew severity by up to 97% but its efficacy declined to 18–55% control as the epidemic progressed. Unlike on young leaves, on older leaves the control of powdery mildew by T. harzianum T39 was poor. Ampelomyces quisqualis (AQ10) was very effective against powdery mildew, achieving up to 98% of control. Its effectiveness declined with the progress of the epidemic but unlike the other biocontrol agent it retained significant control capability on older leaves. Two aliphatic petroleum distillate oil products improved the efficacy of both biocontrol agents. The co-application of T. harzianum T39 and A. quisqualis AQ10 was tested on cucumber plants infected with powdery mildew followed by fruit gray mold infection. It resulted in no improvement of the control of powdery mildew, and in an improvement of gray mold control, the latter probably because of the use of additive oil (ADDQ) along with the second biocontrol preparation. There was no significant interference between the biocontrol agents in the co-application treatment as compared with the application of each agent alone; the level of population of T. harzianum T39 remained similar and the parasitism of S. fusca by A. quisqualis was not nullified. The application of T. harzianum T39 to soil instead of spraying it resulted in 75–90% lower powdery mildew coverage on the leaves. It was concluded that the mode of action of T. harzianum T39 in powdery mildew control is induced resistance, not mycoparasitism or antibiotic action.

Control of infection and sporulation ofBotrytis cinerea on bean and tomato by saprophytic bacteria and fungi

Sixty isolates of saprophytic microorganisms were screened for their ability to reduce the severity of grey mould (Botrytis cinerea) infection and sporulation. Isolates of the bacteriaXanthomonas maltophilia, Bacillus pumilus, Lactobacillus sp., andPseudomonas sp. and the fungusGliocladium catenulatum reduced germination of conidia of the pathogen and controlled disease on bean and tomato plants. Their activity under growth room conditions was good, consistent, and similar to the activity of the known biocontrol agent,Trichoderma harzianum T39 (non-formulated). Although the tested isolates may for nutrients with the germinating conidia ofB. cinerea, resistance induced in the host by live or dead cells were also found to be involved. Inhibitory compounds were not detected on treated leaves. Sporulation ofB. cinerea after its establishment on leaves was also reduced by the above mentioned isolates and byPenicillium sp.,Arthrinium montagnei, Ar. phaeospermum, Sesquicillium candelabrum, Chaetomium globosum, Alternaria alternata, Ulocladium atrum, andT. viride. These sporulation-inhibiting fungi did not reduce the infection of leaves byB. cinerea. Most of these selected fungi and bacteria were capable of reducing lesion expansion.

Controlling Gray Mold on Container-Grown Douglas-Fir by Modified Styroblocks and Under-Bench, Forced Air Ventilation

Abstract Gray mold (Botrytis cinerea) control on Douglas-fir (Pseudotsuga menziesii) seedlings was investigated using under-bench ventilation and styroblocks (growing containers) modified with vertical ventilation holes to allow air movement through the seedling canopy. Gray mold incidence and severity were reduced in three treatments: modified styroblocks with aeration holes at each intercavity intersection and vented from below with heated forced air, like the preceding treatment, but vented with unheated forced air, and modified styroblocks vented with unheated unforced air. In vented styroblocks, gray mold occurred on 25% of the 7-month-old seedlings compared to greater than 75% incidence in unmodified (control) styroblocks. Disease on individual seedlings was also less severe in ventilated styroblocks. The reduced incidence of gray mold in the treatments with ventilation was attributed to more rapid drying of seedling foliage following irrigation. The lowest incidence of humidity and temperature episodes that were ideal for gray mold spore germination and infection occurred in the canopy of seedlings grown in the unheated forced air ventilation treatment There were no practical differences in seedling heights or root collar diameters among treatments. Use of ventilated styroblocks should significantly reduce both gray mold losses and fungicide usage in nurseries. West. J. Appl. For. 5(3):75-79, July 1990