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1.
ABSTRACT The effect of components of primary inoculum dispersal in soil on the temporal dynamics of Phytophthora blight epidemics in bell pepper was evaluated in field and growth-chamber experiments. Phytophthora capsici may potentially be dispersed by one of several mechanisms in the soil, including inoculum movement to roots, root growth to inoculum, and root-to-root spread. Individual components of primary inoculum dispersal were manipulated in field plots by introducing (i) sporangia and mycelia directly in soil so that all three mechanisms of dispersal were possible, (ii) a plant with sporulating lesions on the soil surface in a plastic polyvinyl chloride (PVC) tube so inoculum movement to roots was possible, (iii) a wax-encased peat pot containing sporangia and mycelia in soil so root growth to inoculum was possible, (iv) a wax-encased peat pot containing infected roots in soil so root-to-root spread was possible, (v) noninfested V8 vermiculite media into soil directly as a control, or (vi) wax-encased noninfested soil as a control. In 1995 and 1996, final incidence of disease was highest in plots where sporangia and mycelia were buried directly in soil and all mechanisms of dispersal were operative (60 and 32%) and where infected plants were placed in PVC tubes on the soil surface and inoculum movement to roots occurred with rainfall (89 and 23%). Disease onset was delayed in 1995 and 1996, and final incidence was lower in plants in plots where wax-encased sporangia (6 and 22%) or wax-encased infected roots (22%) were buried in soil and root growth to inoculum or root-to-root spread occurred. Incidence of root infections was higher over time in plots where inoculum moved to roots or all mechanisms of dispersal were possible. In growth-chamber studies, ultimately all plants became diseased regardless of the dispersal mechanism of primary inoculum, but disease onset was delayed when plant roots had to grow through a wax layer to inoculum or infected roots in tension funnels that contained small volumes of soil. Our data from both field and growth-chamber studies demonstrate that the mechanism of dispersal of the primary inoculum in soil can have large effects on the temporal dynamics of disease.  相似文献   

2.
Organic soil amendments including composted cotton gin trash, composted poultry manure, an incorporated rye-vetch green manure, or synthetic fertilizer were applied to subplots, and main plots were either tilled frequently or surface-mulched in experimental field plots between 1997 and 2004. Soil from each replication of the tillage and fertility treatments was sampled in August of 2001, 2002, and 2003, brought to the greenhouse, and infested with Phytophthora capsici to study the effect of previous soil treatments on disease incidence and dispersal of the pathogen. Both the previous tillage and fertility amendments affected the incidence of disease and dispersal of the pathogen. Final disease incidence, AUDPC and the distance of pathogen spread were significantly greater in soils with previous surface mulch applications than in frequently tilled soils. Final disease incidence, AUDPC and the distance of pathogen spread were also significantly higher in soils amended with cotton gin trash, than rye-vetch green manure, poultry manure, or synthetic fertilizer. Soils amended with cotton gin trash had higher soil water content, lower bulk density, higher humic matter content, higher porosity and higher levels of mineralizable N, than soils with other fertility amendments. Soil water content, soil porosity, humic matter content, and net mineralizable levels nitrogen were positively correlated and bulk density was negatively correlated with final incidence of disease.  相似文献   

3.
ABSTRACT Spread of strawberry anthracnose, resulting from the rain splash dispersal of Colletotrichum acutatum conidia, was determined in field plots by assessing fruit disease incidence at a range of distances from an introduced point source of infected fruit with sporulating lesions. Four within-row plant densities were established in replicated plots in each of 2 years. A generalized linear model with a logit link function and binomial distribution for incidence was used to quantify the effects of distance and side of the row relative to the inoculum source, plant density treatment, and their interactions on disease incidence. At all assessment times, there was a significant (P 相似文献   

4.
We studied, by means of field experiments, the combined effects of irrigation system, mulching material and genetic resistance on the incidence of strawberry anthracnose caused by Colletotrichum acutatum. All trials involved artificial inoculation with fruits colonized by the pathogen. One experiment examined the effects of drip irrigation, overhead sprinkler irrigation, and localized low-pressure tape irrigation, and the effects of grass (Brachiaria sp.) and plastic (polyethylene) mulches, in a split plot, randomized complete block design with four replicates. Lower disease incidence, indicating lower pathogen dispersal, was verified with low-pressure tape and drip irrigation. Flower blight and fruit rot incidence in drip-irrigated plots was minimal (ca. 2% of the disease levels in the plots otherwise irrigated). Grass mulch reduced flower blight in the sprinkler system (up to 80%), but had no significant effect when disease levels were already low due to use of other irrigation systems. A second experiment compared the effects of grass mulch, pine (Pinus elliotti) mulch, and plastic mulch with overhead sprinkler irrigation on strawberry cultivars partially resistant (‘Dover’) and susceptible (‘Campinas’) to the disease in a factorial completely randomized design (CRD). Both organic mulches reduced flower blight and diseased fruit incidence by up to 76% compared to the plastic mulch treatment, especially in the early stages of the epidemics. ‘Dover’ had 70% lower incidence of flower blight than ‘Campinas’, and the effects of organic mulches were more pronounced in ‘Campinas’. A third experiment, with all three irrigation systems combined with inoculated and non-inoculated plots, estimated yield effects due to disease and irrigation system. All plots were covered with plastic mulch in a CRD with six treatments. This experiment clearly confirmed the higher flower blight and fruit rot incidences when sprinkler irrigation was used. In inoculated treatments, fruit yield was significantly reduced in tape-irrigated plots, and more so in sprinkler-irrigated plots. In drip-irrigated plots yield was reduced by only 1%. Overall, our results confirm the importance of cultural and genetic factors as valuable means of strawberry anthracnose management. Adoption of localized irrigation systems, the use of organic mulches and choice of a partially resistant cultivar significantly reduced disease levels in field plots. The importance of water splash for C. acutatum dispersal and its dependency on the soil mulch characteristics are the likely causes for the results observed.  相似文献   

5.
Horizontal dispersal of beet necrotic yellow vein virus (BNYVV) by means of viruliferous zoospores ofPolymyxa betae was studied in greenhouse experiments. BNYVV was not detected in roots of sugar beet plants grown in silver sand for 4 weeks at a root-free distance of 5 cm from eitherP. betae- and BNYVV-infected plants or BNYVV-infested soil. Spread of BNYVV from inoculum sources in the field was studied in the absence and presence of tillage practices. Active dispersal in combination with root growth from and towards point sources of inoculum contributed only little to horizontal dispersal of viruliferous inoculum and spread of disease during the season, as determined for one soil type, two different years and in the absence of tillage and tread. In the second beet crop after application of inoculum to whole field plots, more BNYVV-infected plants were detected at 2 m than at 8 m distance from the infested plots in the tillage direction. In the third year, disease incidence at 8 m was high and equivalent to that at 2 m.  相似文献   

6.
Aritua  Legg  Smit  & Gibson 《Plant pathology》1999,48(5):655-661
A study compared the spread of sweet potato virus disease (SPVD) into crops of two moderately resistant and initially SPVD-free sweet potato cultivars in northern and southern Mpigi, Uganda. Whiteflies, the vector of sweet potato chlorotic stunt crini virus (SPCSV), a component cause of SPVD, were similarly abundant in farmers' sweet potato fields around Namulonge in northern Mpigi, and Kanoni in southern Mpigi. However, mean incidence of SPVD in farmers' crops neighbouring the trials was higher at Kanoni (13.3%) than at Namulonge (2.8%). Furthermore, spread of SPVD into initially SPVD-free sweet potato plots of two only moderately resistant cultivars was greater in plots at Kanoni than in plots at Namulonge. The SPVD-resistant New Kawogo was the most common cultivar grown in farmers' fields at Namulonge and had few diseased plants, whereas susceptible cultivars with relatively high incidences of disease predominated at Kanoni. Final SPVD incidence in each trial was positively correlated with a measure combining the proximity and level of inoculum in surrounding fields. The study demonstrates the importance of local SPVD inoculum in determining the rate of spread of the disease into fields and implies that the widespread cultivation of a resistant variety limits infection of susceptible cultivars grown nearby.  相似文献   

7.
According to the results of bioassay studies, 50 p.p.m. and higher dosages of fentin acetate inhibited the growth of Phytophthora citrophthora in situ. Zoospore movement of P. citrophthora varied between 3 and 15 min at 0.5, 1, 10, 100 and 500 p.p.m. fentin acetate. The fungicide also inhibited fruit infections caused by P. citrophthora zoospores at 5 p.p.m. concentration, and protected citrus seedling roots against infection by the fungus at 20–50 p.p.m. concentrations in water culture. Fruit infection was significantly lower in fentin acetate plots than in those without fungicide applications. Stem infection was 15.5 and 8.3% when fentin acetate was applied one or three times respectively as a soil drench in a lemon orchard, but reached 74.9%) in control plots. Fentin acetate treatment decreased inoculum potential to 1/2 and 1/128 in the root zone from the first to the third application.  相似文献   

8.
Point pattern analysis (fitting of the beta-binomial distribution and binary form of power law) was used to describe the spatial pattern of natural take-all epidemics (caused by Gaeumannomyces graminis var. tritici ) on a second consecutive crop of winter wheat in plots under different cropping practices that could have an impact on the quantity and spatial distribution of primary inoculum, and on the spread of the disease. The spatial pattern of take-all was aggregated in 48% of the datasets when disease incidence was assessed at the plant level and in 83% when it was assessed at the root level. Clusters of diseased roots were in general less than 1 m in diameter for crown roots and 1–1·5 m for seminal roots; when present, clusters of diseased plants were 2–2·5 m in diameter. Anisotropy of the spatial pattern was detected and could be linked to soil cultivation. Clusters did not increase in size over the cropping season, but increased spatial heterogeneity of the disease level was observed, corresponding to local disease amplification within clusters. The relative influences of autonomous spread and inoculum dispersal on the size and shape of clusters are discussed.  相似文献   

9.
Guest D 《Phytopathology》2007,97(12):1650-1653
ABSTRACT Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes significant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The global and highly damaging P. palmivora attacks all parts of the cocoa tree at all stages of the growing cycle. This pathogen causes 20 to 30% pod losses through black pod rot, and kills up to 10% of trees annually through stem cankers. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum. This results in explosive epidemics during favorable environmental conditions. The spread of regional pathogens must be prevented by effective quarantine barriers. Resistance to all these Phytophthora species is typically low in commercial cocoa genotypes. Disease losses can be reduced through integrated management practices that include pruning and shade management, leaf mulching, regular and complete harvesting, sanitation and pod case disposal, appropriate fertilizer application and targeted fungicide use. Packaging these options to improve uptake by smallholders presents a major challenge for the industry.  相似文献   

10.
Citrus postbloom fruit drop (PFD) is caused by Colletotrichum acutatum and C. gloeosporioides. These pathogens attack the flowers and cause premature fruit drop and the retention of fruit calyces. This study was designed to characterize the spatial and temporal dynamics of PFD in commercial citrus‐growing areas to better understand the disease spread. Experiments were carried out in three young orchards (500 trees each) in two municipalities in Sao Paulo State, Brazil. Symptoms of PFD on the flowers and presence of persistent calyces were assessed in each of three orchards for three years. Logistic, Gompertz and monomolecular models were fitted to the incidence data over time from the trees with symptoms. The spatial pattern of diseased trees was characterized by a dispersion index and by Taylor′s power law. An autologistic model was used for the spatiotemporal analysis. The logistic model provided the best fit to the disease incidence data, which had a fast progress rate of 0·53 per day. During the early epidemic of PFD, the spatial pattern of diseased trees was random, which suggested that inoculum spread was due to mechanisms other than rain splash. As the disease incidence increased (up to 12·6%), the spatial pattern of diseased trees became aggregated. The rapid rate of disease progress and the distribution of PFD suggest that dispersal of the pathogen is possibly related to a mechanism other than splash dispersal, which is more typical of other fruit diseases caused by Colletotrichum spp.  相似文献   

11.
Holb IJ  Scherm H 《Phytopathology》2007,97(9):1104-1111
ABSTRACT Epidemic development of brown rot, caused by Monilinia fructigena, was monitored in integrated and organic apple orchards at two locations in eastern Hungary between 2002 and 2005 on three cultivars with early, midseason, and late ripening periods. Disease incidence and severity measures were affected significantly (P < 0.05) by management system (organic versus integrated) and cultivar, but there was no significant management system-cultivar interaction. Epidemics started 2 to 4 weeks earlier in organic orchards and on the early cv. Prima compared with integrated orchards and the late cv. Mutsu. Disease intensity increased markedly in the final 3 to 5 weeks before harvest and was considerably lower in integrated than in organic orchards. Final brown rot incidence on fruit in the tree was correlated with incidence on dropped fruit on the orchard floor (r > 0.75, P < 0.05), whereby the lag period from the appearance of the first symptomatic fruit on the ground to the occurrence of the first symptomatic fruit in the tree ranged from 2 weeks to 2 months, depending on the cultivar. The inflection point of the disease progress curve was attained first by fruit on the ground, followed successively by fruit in the lower, middle, and upper thirds of the tree canopy. This may indicate that dropped fruit that became infected early provided a source of inoculum for subsequent epidemics by serving as a bridge between sporulation from overwintered fruit mummies in the spring and the first fruit with sporulating lesions in the tree in midsummer. Removal of dropped fruit from the orchard floor resulted in a significantly lower disease incidence on fruit in the tree on all cultivars; thus, drop-removal may be useful as a brown rot management practice in apple orchards.  相似文献   

12.
The effect of fosetyl-aluminium on the control and spread of brown rot disease Phytophthora citrophthora in post-harvest citrus fruit was studied in laboratory and semi-commercial experiments. Aqueous solutions of fosetyl-aluminium at 5 to 10 g a.i. litre?1 controlled the fungus even when applied 3 days after inoculation at 17°C. No mycelia developed on the peel surface of treated fruit. The fungicide exerted a good prophylactic effect on healthy fruit, protecting them during storage from contact inoculation. Fosetyl-aluminium also showed a fungitoxic effect in vitro and in vivo on other fungi which developed in harvested citrus fruits. Residue levels of phosphoric acid in the treated fruit were higher when the fungicide was incorporated in the wax coating the fruit than when applied in aqueous solution, and levels were lower in the pulp than in the peel. It is concluded that fosetyl-aluminium is a suitable commercial post-harvest treatment for control of brown rot in citrus fruits.  相似文献   

13.
ABSTRACT Brown rot, caused by Monilinia fructicola, is a destructive disease of stone fruit in California. Disease management requires information on inoculum dynamics and development of latent and visible fruit infections during the season to help make decisions on timing of fungicide treatments and choice of cultural practices. In this study, the daily spore concentration (ascospores and conidia) of M. fructicola in the air was monitored with spore traps in two prune orchards during the growing seasons in 2001 and 2002. The spore concentrations were low to moderate at early bloom, increased at full bloom, and decreased to the lowest level at the end of bloom. Improper timing of fruit thinning and irrigation in midseason increased spore concentration in the air and fruit infections late in the season. Artificial fruit inoculations were conducted periodically in 10 prune orchards in 2002 and 2004, and incidence of fruit rot at different inoculation dates was assessed. Fruit rot development rate increased linearly with inoculation date during the growing season. Natural blossom and fruit infections were monitored periodically in 10 prune orchards, and incidence of latent fruit infection was determined by using the overnight freezing-incubation technique. Incidence of fruit rot also was assessed 2 weeks before harvest in these orchards. The incidence of latent fruit infection at the pit hardening stage significantly correlated with that at the late stages and with the incidence of fruit rot at harvest.  相似文献   

14.
Field trials in 1996, 1997 and 1998 with six potato cultivars differing in levels of foliar and tuber race-nonspecific resistance to late blight were treated with 100, 50 and 33% of the recommended dose of the fungicide fluazinam at application intervals of 7, 14 and 21 days. Using a mixed inoculum of six or seven indigenous isolates of Phytophthora infestans small potato plots were inoculated via infector plants. A foliar blight model for the relationship between the effects of resistance, fungicide application and disease pressure was developed using multiple regression analysis. Cultivars with a high level of quantitative resistance offered the greatest potential for fungicide reduction. The model showed that the effect of resistance on integrated control increased exponentially with increasing cultivar resistance. Reducing fungicide input by lowering the dose resulted in less foliar disease than extending application intervals. The higher the disease pressure, the greater the risk associated with reducing fungicide input by extension of application intervals. The field resistance of cultivars to tuber blight mainly determined the frequency of tuber infection. Exploiting high foliar resistance to reduce fungicide input carried a high risk when cultivar resistance to tuber blight was low. When field resistance to tuber blight was high, a medium level of resistance in the foliage could be exploited to reduce fungicide dose to c . 50%, provided application was at the right time. At a high level of field resistance to both foliar and tuber blight, application intervals could be extended.  相似文献   

15.
Dispersal of Phytophthora capsici and P. parasitica from point sources buried near the upper end of 74 m-long irrigation furrows was studied with three annual host crops. Furrows next to tomato were inoculated with either P. capsici or P. parasitica , while furrows next to pepper and squash were inoculated with P. capsici only. Irrigation was carried out on a 14-day cycle. Dispersal of each fungus in the water was monitored by transplants in the furrows and the incidence of infected tomato fruit along furrows. Disease gradients on roots and shoots of all hosts were also measured. Repeated irrigations dispersed P. capsici and P. parasitica up to 70 m from the source. Fruit infection increased with increasing distances downstream, suggesting an accumulation of secondary inoculum with the repeated flow of water. Conversely, gradients of disease severity on roots of tomato and pepper peaked at the source and rapidly decreased to low levels up to 32 m downstream. Fruit and root infection upstream from source was negligible. Root and crown rot in squash was highly variable, being confined to locations near the initial inoculum in some units while developing to severe levels several meters downstream in other units. Unlike the other hosts, squash petioles were in contact with the irrigation water and may have served as routes of invasion by P. capsici. Transport of inoculum from the furrow water to the roots was limited. P. capsici isolates were more virulent on tomato roots and caused a higher incidence of buckeye rot on tomato fruit than did isolates of P. parasitica.  相似文献   

16.
ABSTRACT The spread of Fusarium head blight of wheat from a small area inoculum source was examined in wheat plots (100, 625, or 2,500 m(2)) inoculated in the center with Gibberella zeae-colonized corn kernels or macro-conidia sprayed on heads at anthesis. With the first inoculation method, disease foci were produced from ascospores released from perithecia formed on inoculated kernels. With the second inoculation method, disease foci were produced by macroconidia directly applied to the heads. Some plots were misted during anthesis. Plots were divided into grids, and disease incidence on spikelets and seeds was assessed at the grid intersections. Isopath contour maps were constructed using an interpolation procedure based on a weighted least squares method. Disease gradients were constructed from the isopath contours in the direction parallel to average nightly wind vectors using an exponential model. This study was conducted over a 3-year period at two sites: one in Quebec and one in Ontario. Both inoculation methods resulted in a discrete, primary focus of head blight in each plot, with one or two smaller secondary foci in some plots. The highest incidence of disease on spikelets or seed was commonly displaced somewhat from the inoculum source, usually downwind. The gradient slopes of seed and spikelet infection ranged from -0.10 to -0.43 m(1) in plots with ascospore inoculum and from -0.48 to -0.79 m(1) in plots inoculated with macroconidia. Seed infection declined to 10% of the maximum within 5 to 22 m from the focal center in asco-spore-inoculated plots, and within 5 m in a macroconidia-inoculated plot. Gradients were usually steeper upwind compared with downwind of the inoculum source. In misted plots, incidence of disease was higher and more diffuse than in nonirrigated plots. Based on gradients and dispersal patterns, disease foci in plots inoculated with G. zeae-colonized corn kernels probably arose from airborne ascospores rather than from splash-borne macroconidia and were the result of infection events that occurred over a short period of time. Comparison of conidial- and ascospore-derived disease gradients indicated a lack of secondary infection, confirming that Fusarium head blight is primarily a monocyclic disease.  相似文献   

17.
Asiatic citrus canker is a potentially severe disease of several citrus species and cultivars in many tropical and subtropical areas. In such areas, infected nursery plants constitute an important source of primary inoculum for newly established citrus groves. The influence of overhead, drip, and mist irrigation systems on the development of Asiatic citrus canker was studied in simulated, Mexican-lime nurseries in Reunion Island. Overhead irrigation exacerbated the increase of disease incidence and severity caused by a streptomycin-resistant strain of Xanthomonas axonopodis pv. citri. The temporal development of Asiatic citrus canker for overhead irrigated nursery plots was best described by an exponential model, because disease incidence in these plots did not come close to an asymptote during the experimental period. This can be explained by the continuous production of new growth, susceptible to infection by Xanthomonas axonopodis pv. citri, and splash dispersal of Xanthomonas axonopodis pv. citri associated with overhead irrigation. Based on spatial correlation and spatio-temporal analyses, aggregated disease patterns were found irrespective of the irrigation system. In overhead-irrigated plots, the spread of Xanthomonas axonopodis pv. citri lacked directionnality. Rainstorms of short duration and high intensity were apparently associated with disease increase in drip-irrigated plots. There is a need to improve cultivation practices in Reunion Island citrus nurseries to minimize Asiatic citrus canker incidence in nurseries and to minimize the introduction of Xanthomonas axonopodis pv. citri to new groves.  相似文献   

18.
Management of grape powdery mildew (Erysiphe necator) and other polycyclic diseases often relies on calendar‐based pesticide application schedules that assume the presence of inoculum. An inexpensive, loop‐mediated isothermal amplification (LAMP) assay was designed to quickly detect airborne inoculum of E. necator to determine when to initiate a fungicide application programme. Field efficacy was tested in 2010 and 2011 in several commercial and research vineyards in the Willamette Valley of Oregon from pre‐bud break to véraison. In each vineyard, three impaction spore traps were placed adjacent to the trunk. One trap was maintained and used by the grower to conduct the LAMP assay (G‐LAMP) on‐site and the other two traps were used for laboratory‐conducted LAMP (L‐LAMP) and quantitative PCR assay (qPCR). Using the qPCR as a gold standard, L‐LAMP was comparable with qPCR in both years, and G‐LAMP was comparable to qPCR in 2011. Latent class analysis indicated that qPCR had a true positive proportion of 98% in 2010 and 89% in 2011 and true negative proportion of 96% in 2010 and 64% in 2011. An average of 3·3 fewer fungicide applications were used when they were initiated based on spore detection relative to the grower standard practice. There were no significant differences in berry or leaf incidence between plots with fungicides initiated at detection or grower standard practice plots, suggesting that growers using LAMP to initiate fungicide applications can use fewer fungicide applications to manage powdery mildew compared to standard practices.  相似文献   

19.
Downy mildew of hop, caused by Pseudoperonospora humuli , is an important disease in most regions of hop production and is managed largely with regular fungicide applications. A PCR assay specific to P . humuli and the related organism P .  cubensis was developed and used to monitor airborne inoculum in hop yards to initiate fungicide applications. The PCR amplified as little as 1 fg of genomic DNA of P . humuli , and yielded an amplicon in 70% of reactions when DNA was extracted from single sporangia. In the presence of 25 mg of soil, an amplicon was amplified in 90% of reactions when DNA was extracted from 10 or more sporangia. During nine location-years of validation, PCR detection of the pathogen in air samples occurred no later than 8 days after the appearance of trace levels of disease signs and/or detection of airborne spores in a volumetric spore sampler. Inoculum was detected on average 4·5 days before (range −8 to 14 days) the first appearance of basal spikes in six commercial yards, or 1·3 days after (range −5 to 1 days) sporangia were detected in a volumetric spore sampler in experimental plots. In commercial yards, use of PCR to initiate the first fungicide application led to enhanced disease control or a reduction in fungicide use in four of six yards compared to growers' standard practices. These results indicate that the efficiency and efficacy of hop downy mildew management can be improved when control measures are timed according to first detection of inoculum.  相似文献   

20.
Sang MK  Kim JD  Kim BS  Kim KD 《Phytopathology》2011,101(6):666-678
We previously selected rhizobacterial strains CCR04, CCR80, GSE09, ISE13, and ISE14, which were antagonistic to Phytophthora blight of pepper. In this study, we investigated the effects of root treatment of rhizobacteria on anthracnose occurrence, ripening, and yield of pepper fruit in the plastic house and field in 2008 and 2009. We also examined the effects of volatiles produced by the strains on fruit ripening and on mycelial growth and spore development of Colletotrichum acutatum and Phytophthora capsici in the laboratory, identifying the volatile compounds by gas chromatography-mass spectrometry (GC-MS). In the house tests, all strains significantly (P < 0.05) reduced anthracnose incidence on pepper fruit; strains GSE09 and ISE14 consistently produced higher numbers of pepper fruit or increased the fresh weight of red fruit more than the controls in both years. In the field tests, all strains significantly (P < 0.05) reduced anthracnose occurrence on either green or red pepper fruit; strain ISE14 consistently produced higher numbers or increased fresh weights of red fruit more than the controls in both years. In the laboratory tests, volatiles produced by strains GSE09 and ISE13 only stimulated maturation of pepper fruit from green (unripe) to red (ripe) fruit; the volatiles of certain strains inhibited the growth and development of C. acutatum and P. capsici. On the other hand, GC-MS analysis of volatiles of strains GSE09 and ISE13 revealed 17 distinct compounds in both strains, including decane, dodecane, 1,3-di-tert-butylbenzene, tetradecane, 2,4-di-tert-butylphenol, and hexadecane. Among these compounds, 2,4-di-tert-butylphenol only stimulated fruit ripening and inhibited growth and development of the pathogens. Taken together, strains GSE09 and ISE14 effectively reduced anthracnose occurrence and stimulated pepper fruit ripening and yield, possibly via bacterial volatiles. Therefore, these two strains could be potential agents for controlling Phytophthora blight and anthracnose, and for increasing fruit ripening and yield. To our knowledge, this is the first report of volatiles such as 2,4-di-tert-butylphenol produced by rhizobacteria being related to both fruit ripening and pathogen inhibition.  相似文献   

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