scholarly journals Detection of Colletotrichum acutatum latent infections in strawberry petioles and leaves

2008 ◽  
Vol 23 (4) ◽  
pp. 235-241
Author(s):  
Natasa Duduk ◽  
Mirko Ivanovic ◽  
Bojan Duduk
Keyword(s):  
Plant Tissue ◽  
Low Temperatures ◽  
Plant Material ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Tween 20 ◽  
Surface Sterilization ◽  
Plant Parts ◽  
Symptomless Plant ◽  
Freezing Procedure

Colletotrichum acutatum is the most significant agent of anthracnose strawberry fruit rot. Besides being a necrotrophic pest, it can spend a part of its life cycle as an epiphyte, in a form of latent infection. The presence of the fungi on symptomless plant tissue is considered one of the main ways of distribution of this economically harmful pathogen in the world. Investigation of latent C. acutatum infection was carried out on artificially inoculated strawberries. The initiation of fungi sporulation on symptomless petioles and leaves was carried out by exposing them to the herbicide paraquat (0.25%) and low temperatures, which caused plant tissue decay in different ways. Surface sterilization with 0.5% NaOCl precedes the exposure of plant material to paraquat. The freezing procedure was carried out by exposure of plant material to the temperature of -20?C for 2h. After the freezing, one group was rinsed in Tween 20 (18 ?l/l), and another group underwent surface sterilization in 0.0525% NaOCl with an addition of Tween 20 (18 ?l/l). After 6 days of incubation, the appearance of acervuli and conidia was detected in 93.33 to 100% plant parts exposed to paraquat treatment and freezing procedure. In inoculated parts which were not exposed to herbicides or low temperatures, the presence of acervuli was detected in 3.33% tested petioles and 6.67% leaves.

scholarly journals Overwintering Diseased Plant Parts and Newly Infected Flowers and Fruit as Sources of Inoculum for Colletotrichum acutatum in Sour Cherry

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1207-1213 ◽  
Author(s):  
Arne Stensvand ◽  
Jorunn Børve ◽  
Venche Talgø
Keyword(s):  
Plant Material ◽  
Infected Plant ◽  
Sour Cherry ◽  
Growing Season ◽  
Early Spring ◽  
Tissue Type ◽  
Colletotrichum Acutatum ◽  
Diseased Plant ◽  
Plant Parts ◽  
Southern Norway

Production of inoculum of Colletotrichum acutatum from both previously infected and overwintered tissue, as well as newly developed plant tissue of sour cherry (Prunus cerasus), was studied in southern Norway. Plant parts were sampled from commercial, private, or research orchards, and incubated for 2 to 14 days (time depended on tissue type) in saturated air at 20°C. In early spring, abundant sporulation was found on scales of overwintered buds and shoots. A mean of 35% infected buds in four cultivars was observed, with a maximum of 72% of the buds infected in one of the samples. Over 3 years, the seasonal production of overwintered fruit and peduncles of cv. Fanal infected the previous year was investigated. In all three years, the infected plant material was placed in the trees throughout the winter and the following growing season; in two of the years, fruit and peduncles were also placed on the ground in the autumn or the following spring. Old fruit and peduncles formed conidia throughout the season, with a peak in May and June. Spore numbers declined over the season, but the decline was more rapid for plant material on the ground than in the trees. On average over 2 years, 68.7, 24.0, or 7.3% of the inoculum came from fruit placed in the trees, placed on the ground in spring, or placed on the ground the preceding autumn, respectively. The number of fruit and peduncles attached to the trees in a planting of cv. Hardangerkirsebær was followed from February to July one year, and although there was a decline over time, fruit and/or their peduncles were still attached in substantial numbers in July, thus illustrating their potential as sources of inoculum. In observations over 2 years in a heavily infected orchard of cv. Stevnsbær, 75 and 47% of flowers and newly emerged fruit, respectively, were infected. Artificially inoculated flowers and fruit produced conidia until harvest, with a peak in mid-July. It may be concluded that previously infected and overwintered, as well as newly emerged tissue of sour cherry, may serve as sources of inoculum of C. acutatum throughout the growing season.

Effect of Inoculum Level on Response of Strawberry Fruit to Anthracnose Fruit Rot

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 460c-460
Author(s):  
Joel L. Shuman ◽  
James R. Ballington
Keyword(s):  
North Carolina ◽  
Threshold Level ◽  
Fruit Weight ◽  
Field Resistance ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Inoculum Level ◽  
Breeding Lines ◽  
Plant Parts ◽  
Green Fruit

In North Carolina, anthracnose fruit rot of strawberry (Fragaria × ananassa Duch.) is caused by the fungus Colletotrichum acutatum Simmonds. Little is known about the mechanisms of field resistance of fruits to anthracnose. It appears that resistance of various plant parts including runners, crowns, and foliage is not always correlated with resistance of fruit. Resistance of fruit may be simply overwhelmed by excessive fungal conidia. Is there a threshold level of inoculum and does this threshold vary for fruit of different cultivars? The objective of this study was to determine the effect of inoculum level on the response of seven strawberry cultivars/breeding lines to a single C. acutatum (CA-1) isolate. The experimental design was a split-plot with five levels of inoculum (0, 1 × 103, 1 × 104, 1 × 105, and 1×106 conidia/ml) as the whole plot and seven cultivars/breeding lines (`Apollo', `Chandler', `Camerosa', `Pelican', `Sweet Charley', NCH 95-173, and NCR 94-08) as the subplots with three replicates. The experiment was conducted in a growth chamber at the Southeastern Plant Evironment Laboratory at North Carolina State Univ. Mature, green fruit and fruit turning red were inoculated with conidia. Lesion diameter, percent diseased tissue, and fruit weight were determined daily. The seven cultivars/breeding lines had differing levels of fruit rot resistance and fruit firmness/skin toughness.

Ratio of plant to soil concentrations of strontium-85 and its relation to properties of Greek soils

1991 ◽  
Vol 116 (2) ◽  
pp. 275-279 ◽  
Author(s):  
E. P. Papanicolaou ◽  
C. G. Apostolakis ◽  
V. Skarlou ◽  
C. Nobeli ◽  
P. Kritidis
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Plant Material ◽  
Clay Content ◽  
Exchange Capacity ◽  
Absolute Value ◽  
Plant Parts ◽  
Stems And Leaves ◽  
Lower Variability ◽  
Edible Parts

SUMMARYPlant:soil ratios (CRs) of 85Sr concentration were studied in wheat, lucerne, lettuce, radish, string bean (Phaseolus vulgaris), and cucumber grown in pots in eight Greek soil types in a glasshouse pot experiment in 1989.The CRs of the crops and of the plant parts studied differed according to soil type. They ranged from 0·034–1·39 for wheat grains to 7·6–36·5 for cucumber stems and leaves. The CRs of the edible parts were much lower than those of the other plant material.The correlation between CRs and clay content was negative and, in most cases, significant (P = 0·05–0·01) or highly significant (P < 0·01). The negative correlation improved (higher absolute value of r, lower variability) if clay plus silt content or cation exchange capacity was used instead of clay content.The correlation between CRs and soil properties was greatest for soil pH (r = –0·89) and decreased in the order: pH > total clay plus silt ≃ cation exchange capacity > total clay.

scholarly journals First Report of Anthracnose Caused by Colletotrichum acutatum on Persimmon Fruit in the United States

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 634-634 ◽  
Author(s):  
S. M. Williamson ◽  
T. B. Sutton
Keyword(s):  
United States ◽  
Filter Paper ◽  
The United States ◽  
Grocery Store ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Diospyros Kaki ◽  
Japanese Persimmon ◽  
First Report ◽  
Persimmon Fruit

Persimmon trees are important for their fruit as well as their colorful fruit and foliage in the fall. Persimmon fruit (Japanese persimmon, Diospyros kaki cv. Fuyu) were collected in November 2008 from a tree in Windsor, NC, located in the Coastal Plain. Fruit were not symptomatic on the tree but developed dark lesions after harvest. Isolations from six fruit yielded seven isolates of Colletotrichum acutatum J. H. Simmonds. After incubation at 25°C under continuous light for 15 days on potato dextrose agar (PDA), all isolates had gray aerial mycelium, but the inverse sides of the plates of six isolates were maroon and one was beige. Masses of salmon-colored conidia were formed first in the center of the colonies, then were observed scattered across the colonies in older cultures. Conidia were hyaline, one-celled, elliptic with one or both ends pointed, and measured 8.1 to 16.3 × 3.1 to 5 μm. Setae and sclerotia were not observed. There were also dark structures measuring 1 to 10 mm that were partially embedded in the agar that contained conidia. Cultural and conidial characteristics of the isolates were similar to those of C. acutatum (3). PCR amplification was performed with the species-specific primer pair CaInt2/ITS4 (2) and genomic DNA from the original isolates and isolates obtained from inoculated fruit. An amplification product of approximately 490 bp, which is specific for C. acutatum, was observed. To fulfill Koch's postulates, persimmon fruit obtained from the grocery store were surface disinfested with 0.5% sodium hypochlorite and sterile filter paper disks dipped in conidial suspensions (1 × 105 conidia/ml) of two C. acutatum isolates (maroon and beige reverse) or sterile, deionized water were placed on the fruit. Three fruit were inoculated per treatment and the disks were placed on four locations on each fruit. Parafilm was wrapped around the diameter of the fruit to keep the filter paper disks moist and in place. Fruit were placed in moist chambers and incubated at 25°C. After 3 days, the Parafilm was removed and the fruit returned to the moist chambers. Small, dark lesions were observed on fruit inoculated with each isolate of C. acutatum when the filter paper disks were removed. Ten days after inoculation, dark lesions and acervuli with salmon-colored masses of conidia were observed on fruit inoculated with both isolates of C. acutatum and the fruit were soft. After 12 days, there were abundant masses of conidia and the inoculated areas were decayed. Control fruit remained firm and did not develop symptoms. Cultures obtained from the fruit and the conidia produced were typical of the isolates used to inoculate the fruit. C. acutatum has been reported to cause fruit rot on persimmon fruit in New Zealand (1). To our knowledge, this is the first report of C. acutatum on persimmon fruit in the United States. References: (1) R. Lardner et al. Mycol. Res. 103:275, 1999. (2) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (3) B. C. Sutton. Page 523 in: Coelomycetes. Commonwealth Agricultural Bureaux, Great Britain. 1980.

Identifying and Characterizing Summer Diseases on ‘Babygold’ Peach in South Carolina

2006 ◽  
Vol 7 (1) ◽  
pp. 30 ◽  
Author(s):  
Guido Schnabel ◽  
Wenxuan Chai ◽  
Kerik D. Cox
Keyword(s):  
South Carolina ◽  
Dna Analysis ◽  
Management Strategies ◽  
Disease Outbreaks ◽  
Geotrichum Candidum ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Significant Yield ◽  
Rot Disease

Summer diseases can cause significant yield losses in processing peach varieties, such as the ‘Babygold’ lines. In this study we identified and characterized the pathogens responsible for disease outbreaks in two orchards (PH and JC) located in the northern ‘Piedmont’ area of South Carolina. Three pathogens, Geotrichum candidum, Colletotrichum acutatum, and Botryosphaeria dothidea, the causal agents of sour rot, anthracnose, and Botryosphaeria fruit rot disease respectively, were identified on fruit from orchard PH using symptomology, culture and spore morphology, and ribosomal DNA analysis. G. candidum and C. acutatum were also isolated from symptomatic fruit from orchard JC. The QoI fungicide azoxystrobin and a mixture of pyraclostrobin and boscalid were evaluated for their in vitro efficacy against five isolates of each of the three pathogens to investigate their possible usefulness in designing management strategies. Azoxystrobin inhibited mycelial growth of C. acutatum isolates (EC50 values of 0.01 to 0.55 mg/liter) but was ineffective against mycelium of G. candidum and B. dothidea isolates (EC50 values >300 mg/liter). The pyraclostrobin-boscalid mixture was highly effective against mycelium of C. acutatum (EC50 values of 0.01 to 0.05 mg/liter) and B. dothidea isolates (EC50 values of 0.02 to 0.03 mg/liter), but only marginally effective against mycelium of G. candidum (EC50 values 15.79 to 39.03 mg/liter). This study provides a diagnostic guide of pathogens that can cause summer diseases on ‘Babygold’ peaches and reports their in vitro sensitivity to registered respiration inhibitor fungicides. Accepted for publication 23 December 2005. Published 1 March 2006.

scholarly journals Anthracnose Fruit Rot Resistance in Blueberry Cultivars

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 33-38 ◽  
Author(s):  
James J. Polashock ◽  
Mark K. Ehlenfeldt ◽  
Allan W. Stretch ◽  
Matthew Kramer
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Field Resistance ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Narrow Sense Heritability ◽  
Additive Inheritance ◽  
Postharvest Rot ◽  
Very High ◽  
Important Disease

Anthracnose fruit rot (causal agent, Colletotrichum acutatum) is an important disease in most blueberry growing regions of North America. Losses caused by the disease are usually seen as a postharvest rot with orange spore masses appearing on the surface of affected fruit. One hundred cultivars/selections of blueberry were screened for resistance to fruit rot between 1993 and 2003 by inoculating container-grown plants bearing green fruit. Visible rot symptoms on ripe fruits were evaluated after a 1-week incubation at room temperature. Our analyses revealed that infection levels were affected by mean May temperatures in New Jersey, generally increasing as temperatures increased; however, this effect was not consistent among all cultivars. A generalized linear mixed model was developed to predict resistance at the historic mean May temperature, conservatively explaining 59% of the variance in resistance. Percent infection ranged from 9 to 91% with a mean of 51% across all cultivars. Results for common cultivars corresponded well with field reports of their relative susceptibilities. An estimate of narrow-sense heritability of 0.32 suggested additive inheritance of resistance. Since very high inoculum loads were used in this study, cultivars exhibiting a low percentage of fruit rot are predicted to show superior field resistance to the disease and will be incorporated into an ongoing breeding program.

Decomposition of plant material in Australian soils. II. Residual organic 14C and 15N from legume plant parts decomposing under field and laboratory conditions

Soil Research ◽  
1984 ◽  
Vol 22 (3) ◽  
pp. 331 ◽  
Author(s):  
M Amato ◽  
RB Jackson ◽  
JHA Butler ◽  
JN Ladd
Keyword(s):  
Plant Material ◽  
Calcareous Soil ◽  
Laboratory Studies ◽  
Plant Parts ◽  
Drying And Rewetting ◽  
Legume Plant ◽  
Medicago Littoralis ◽  
Average Residual ◽  
Medicago Species ◽  
Field And Laboratory Conditions

14C- and 12N-labelled Medicago littoralis and Medicago truncatula plant parts, ground or unground, were added at a rate equivalent to 50 kg nitrogen ha-l to a calcareous soil in the field and allowed to decompose for two years. Both plant types behaved similarly but the various plant parts decomposed to different extents. After 4 weeks' and 2 years' decomposition respectively, the residual organic 14C in soil from leaves of both Medicago species accounted for about 62% and 20% of input, from stems 70% and 24% and from roots 80% and 32%. Average residual organic 15N accounted for 64% and 40% of leaf 15N, 87% and 56% of stem and 81% and 50% of root 15N. Grinding had no effect on the residual 14C and 15N of plant parts. After 2 years' decomposition the proportion of residual and 15N present as labelled biomass was greatest for leaf residues. Results from laboratory studies of 20 weeks' decomposition of ground and unground Medicago littoralis plant parts under continuously moist and intermittently dry and rewetting conditions were consistent with field results. Grinding significantly promoted pod decomposition under most incubation conditions. Drying and rewetting promoted decomposition of the plant parts. Pods were affected more than other parts. The longer the time moist following drying, the greater the decomposition. The more frequent the drying and wetting cycles, the greater the decomposition.

scholarly journals Incidence and Causes of Postharvest Fruit Rot in Stored Michigan Cranberries

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1277-1282 ◽  
Author(s):  
R. O. Olatinwo ◽  
A. M. C. Schilder ◽  
A. N. Kravchenko
Keyword(s):  
The Other ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Upper Peninsula ◽  
High Incidence ◽  
Commercial Farms ◽  
Phomopsis Vaccinii ◽  
Northern Michigan ◽  
Growing Region

The incidence of postharvest fruit rot and associated fungi was studied in stored cranberries in Michigan in 2000 and 2001. Ripe cranberries were harvested from eight commercial farms in southwest and northeast Michigan, including the Upper Peninsula. Eight cranberry cultivars were represented: Stevens, Searles, Le Munyon, Pilgrim, Ben Lear, Bergman, Beckwith, and WSU 61. Fruit rot incidence was assessed within 1 week after harvest. Remaining sound fruit was stored for 2 months at 5°C, and fungi were isolated from rotted fruit after 1 and 2 months of storage. Year and region, but not cultivar, significantly affected the overall rate of rot development in storage. Storage rot levels generally were lower in 2001 than in 2000, particularly in southern Michigan. A high incidence of field rot at harvest did not necessarily lead to a high incidence of storage rot. Storage rot tended to be more severe in the northern than in the southern growing region. Fungi most frequently associated with storage rot were Fusicoccum putrefaciens, Colletotrichum acutatum, Coleophoma empetri, Phomopsis vaccinii, and Phyllosticta elongata. F. putrefaciens was the predominant storage rot fungus in northern Michigan in both years and caused up to 80% fruit rot in storage. C. empetri and P. elongata also were isolated more frequently from beds in northern than southern Michigan in 2001. The cvs. Pilgrim and Stevens were more susceptible to storage rot caused by Colletotrichum acutatum, and Bergman and WSU 61 were more susceptible to storage rot caused by Phomopsis vaccinii than some of the other cultivars.

scholarly journals Pre- and Post-Infection Activity of Pyraclostrobin for Control of Anthracnose Fruit Rot of Strawberry Caused by Colletotrichum acutatum

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 862-868 ◽  
Author(s):  
William W. Turechek ◽  
Natália A. Peres ◽  
Nicole A. Werner
Keyword(s):  
New York ◽  
Post Infection ◽  
Field Studies ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Disease Development ◽  
Infection Period ◽  
Significant Control ◽  
Infection Treatment ◽  
Control Equivalent

The effect of pre- and post-infection-period applications of pyraclostrobin (Cabrio EG) on the development of anthracnose fruit rot was characterized in a controlled-climate study and validated in field studies in New York and Florida. Plants of the day-neutral cv. Tristar were inoculated with C. acutatum and placed into mist chambers at 14, 22, or 30°C. The plants were removed from the chambers after 3, 6, 12, or 24 h of misting and placed on greenhouse benches to allow disease development. The fungicide pyraclostrobin was applied to the berries at a concentration equivalent to 168 g a.i./ha at 3, 8, 24, and 48 h prior to inoculation and exposure to their wetting period, or 3, 8, 24, and 48 h following inoculation and exposure to their wetting period. All pyraclostrobin treatments suppressed disease compared with the corresponding untreated control treatments. The highest incidence of disease occurred on plants exposed to the longest wetness durations (12 and 24 h) or highest temperature treatments (22 and 30°C). Post-infection applications of pyraclostrobin provided significant control when applications were made within 3 and often up to 8 h after wetting, but generally were less effective than protective sprays. We further tested the ability of pyraclostrobin to control anthracnose when applied as a protectant or as an after-infection application in inoculated field plots exposed to a short (8 h) or long (24 h) wetting period in Florida and in New York. In three of the four experimental plots, disease control equivalent to or better than the protective spray was achieved when pyraclostrobin was applied up to 24 h after infection for long and short wetting periods. In the remaining plot, conditions for disease development were exceptionally favorable. The protective treatment provided approximately 75% control, whereas the best post-infection treatment provided only 50% control. Our study indicates that for short wetting events, such as those associated with seasonal thunderstorms, growers can wait until after such an infection event before applying pyraclos-trobin and achieve control equivalent to a protective application.

scholarly journals Pestalotia Leaf Spot and Fruit Rot of Strawberry

EDIS ◽  
2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Juliana S. Baggio ◽  
Natalia A. Peres
Keyword(s):  
Plant Pathology ◽  
Leaf Spot ◽  
Fruit Production ◽  
Causal Agent ◽  
Fruit Rot ◽  
Disease Development ◽  
Plant Parts ◽  
Pathology Department ◽  
And Control

Pestalotiopsis-like fungi cause diseases on many different species of plants worldwide, including strawberry. The pathogen is not necessarily new to strawberry and was first reported causing fruit rot in Florida and Israel in the 1970s. However, during the 2018–19 and 2019–20 strawberry seasons, severe and unprecedented outbreaks were reported in Florida, characterized by symptoms on nearly all plant parts including roots, crowns, petioles, fruit, and leaves. This new 4-page publication of the UF/IFAS Plant Pathology Department describes the disease and its causal agent and briefly covers what is known about disease development and control practices. This document will provide valuable information to strawberry nursery and fruit production growers. Written by Juliana S. Baggio and Natalia A. Peres.https://edis.ifas.ufl.edu/pp357

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