Postharvest Fruit Rot Research Articles

First Report of Pulp Rot in Externally Asymptomatic Pomegranate Fruit Caused by Talaromyces albobiverticillius in Henan Province, China.

As a popular deciduous fruit tree, pomegranate (Punica granatum L.) is grown from tropical to temperate zones worldwide, therein China has at least 120000 hm2 cultivation area. In August 2020, severe pulp rot occurred in the externally asymptomatic pre-harvest pomegranate fruit on a 3-year-old soft-seeded variety (Tunisia) in the Zhanghe village (32º40´34˝N, 111º44´20˝E) of Jiuchong township, Xichuan county in Henan province, China with 6.4-20 (av. 12.6) % pulp rot incidence evaluated from 11 freshly sampled fruits (360 pulps per fruit investigated). The fruits showed no external symptoms, however, browning occurred on part of their pulps before harvest compared to the normal ones with white or pink color. The surface of the externally asymptomatic fruits was sterilized with 75% ethanol, and air-dried in a clean bench. The surface-disinfected fruits were dissected with a sterilized knife. Brown pulps from the fruits were picked up using flame-sterilized tweezers and placed on potato dextrose agar (PDA) plates. After five days of incubation at 28 °C, pure fungal cultures with similar phenotypic features developed from the affected pulps. Two randomly selected isolates Tp-2 and Tp-8 were used for the study. The colony surface of the isolates was greyish-green with claret-red exudates. Claret-red pigments were commonly secreted into the medium from the colonies. Conidia were unicellular, hyaline to greyish, mostly rugby ball-shaped with a dimension of 2.2-3.5 (2.7) µm × 1.6-2.0 (1.8) µm (n=50) for Tp-2, and 2.2-3.1 (2.6) µm × 1.6-2.2 (1.8) µm (n=50) for Tp-8. The rDNA internal transcribed spacer (ITS) and β-tubulin gene sequences of the isolates were amplified with primers ITS1/ITS4 and Bt2a/Bt2b, respectively. Sequences were submitted to GenBank with accession numbers MW132153 and MW132077 for the rDNA-ITS sequences, and MW507822 and MW507823 for the β-tubulin gene sequences of Tp-2 and Tp-8, respectively, with a maximal sequence identity greater than 99 % to multiple strains of Talaromyces albobiverticillius (TA) based on BLAST analyses. In the Neighbor-joining phylogenetic trees constructed using rDNA-ITS and β-tubulin gene sequences, both Tp-2 and Tp-8 formed a clade with mutiple strains of TA, clearly separated from other Talaromyces spp. Conidial suspensions (106 spores ml-1) of Tp-2 and Tp-8 were separately injected into five pomegranate fruits (Tunisia) sampled from an orchard free of the disease with a sterilized syringe. Five fruits inoculated with sterilized water were used as control (CK). The inoculated fruits were incubated at 25 °C for 10 days and cut out through the inoculated sites. Pulp rot symptoms occurred in the Tp-2/Tp-8-inoculated fruits, being similar to the naturally affected pulps. The CK pulps remained symptomless during the inoculation tests. Fungal cultures with the same phenotypic features as the inocula were constantly isolated from the brown pulps of the inoculated fruits, verifying both Tp-2 and Tp-8 as the causal agents of the disease based on Koch's postulates. During a long-term (30-40 days) storage at ambient conditions, fruits sampled from affected orchards developed brown lesions on their peels from which TA cultures could be isolated. TA was reported as the pathogen causing postharvest fruit rot on pomegranate in Italy (Mincuzzi et al. 2017). This is the first report of TA causing pulp rot in the externally asymptomatic pomegranate fruit in China.

Diplodia bulgarica, cause of postharvest rot on apples in Turkey

Apple fruit cv. Golden Delicious symptoms of rot were collected from storage in the area of Eğirdir district of Isparta province, in Turkey. Based on morphology and phylogeny of DNA sequence data for the internal transcribed spacer (ITS) rDNA region, the isolated pathogen was identified as Diplodia bulgarica. This is the first description of D. bulgarica causing postharvest fruit rot on Malus domestica cv. Golden Delicious in Turkey and worldwide.

Evaluation of the antifungal activity of essential oils against Alternaria alternata causing fruit rot of Eriobotrya japonica

Abstract Objectives The study was aimed to evaluate the effect of essential oils against fungal pathogens including the chemical analysis (GC-MS) of the most effective essential oil. Methods The antifungal effect of essential oils was assessed after morpho-molecular identification of Alternaria alternata. Mycelial growth inhibition (%) in in vitro treatment of eight essential oils at different concentrations was observed against A. alternata. Fungitoxicity assay was done following chemical composition analysis by Gas chromatography-mass spectrometry. Direct application of thyme oil was performed on healthy fruits against A. alternata. Results All eight essential oils showed mycelial growth inhibition at different levels, whereas thyme oil was found more efficacious against A. alternata. Chemical composition analysis detected 32 components and thymol was found in a higher percentage. Direct application of the most significant concentration of thyme oil was found effective against A. alternata with a varying decrease in decaying percentage. Conclusions Investigation of this study proved thyme oil as a potential and eco-friendly botanical fungicide effectively used against A. alternata on loquat fruit. The current study explored that thyme oil could be potentially used against A. alternata and its compounds could be further investigated for the development of eco-friendly approaches for the control of postharvest fruit rots.

First report of Fusarium sambucinum causing postharvest fruit rot of winter squash (Cucurbita maxima)

First report of Fusarium sambucinum causing postharvest fruit rot of winter squash (Cucurbita maxima)

Chemical characterization of essential oil constituents of three selected botanicals and their antimicrobial activity against postharvest rot pathogens of tomato (Solanum lycopersicum L.)

This study investigated chemical constituents of essential oils (EOs) of Thaumatococcus daniellii, Hyptis suaveolens and Hildegardia barteri and their bioactivity against three tomato fruit rot pathogens, Aspergillus terreus, Fusarium oxysporum and Geotrichum candidum. The EOs were extracted using hydro distillation, and their chemical composition was determined by gas chromatography and mass spectrometry, while inhibition was determined by Agar diffusion method. Sesquiterpene hydrocarbons were the major constituents of the EOs of T. daniellii (38.7%), H. suaveolens (49.48%) and H. barteri (48.1%). Caryophyllene, guaiol and β-cubebene were the most predominant constituents of T. daniellii, H. suaveolens and H. barteri EOs, respectively. The EOs effectively inhibited radial growth of the pathogens in the in vitro bioassay and their efficacy was significantly higher than mancozeb. This study has shown the prospects of the EOs and sets the pace for further research in the management of postharvest tomato fruit rot under field conditions.

First report of Neopestalotiopsis clavispora causing postharvest fruit rot of loquat in Pakistan

First report of Neopestalotiopsis clavispora causing postharvest fruit rot of loquat in Pakistan

IN VITRO EVALUATION OF DIFFERENT LOCALLY AVAILABLE PRESERVATIVES AGAINST THE FUNGUS CAUSING TOMATO FRUIT ROT DISEASE

The post-harvest tomato fruit rot caused by Alternaria solani is a major threat to the tomato fruits. Our main objective of this study was to assess the locally available plant based preservatives against post-harvest tomato fruit rot. The in-vitro antifungal effect of 09 different treatments (07 plants based = black pepper, red pepper, turmeric, clove, garlic, onion and papaya seed and 02 chemical preservatives = Potassium metabi-sulphate, PMS and Sodium benzoate, SB) showed significant (P < 0.05 = 0.0000) variation among the treatment groups. Black pepper followed by red pepper and turmeric remained the best antifungal and preservative after 05, 10 and 15 days after treatment (DAT) in B-group (inoculated and uninjured fruits). However, in A-group (inoculated and injured fruits), lowest infection percent was recorded for black pepper followed by red pepper and turmeric after 05, 10 and 15 DAT. The response of all treatments was obvious after 15 DAT. No infection of test fungus was recorded when black pepper and red pepper were applied. Whereas, with the application of turmeric (8.33%) and garlic (9.33%) lowest infection percent was observed with no significant difference. The response of onion (4.33%), papaya seed (6%), clove (7.66%) and SB (15%) appeared moderate with no significant difference. After 30 days, the lowest number of spoilt fruits were recorded with the treatment of black pepper (01) and red pepper (01) followed by turmeric (02), clove (02), onion (02) and SB (02) in B-group. Based on best physical structure, maximum numbers of tomato fruits were observed in clove (04) followed by black pepper (03) and SB (03) when treated without any injury (B group). While in case of A group, almost all fruits in all treatments become spoilt after 30 days of treatment. It has been proved that locally available plant based preservatives have an excellent antifungal and preservative potential against post-harvest tomato fruit rot disease caused by Alternaria solani. These plant based preservatives increase the shelf-life of tomatoes without any health hazards. To the best of our knowledge, this is the first time conducted study, where antifungal and preservative potential of locally available plant products against post-harvest tomato fruit rot caused by Alternaria solani have been explored.

First Report of Postharvest Fruit Rot Disease of Hardy Kiwifruit Caused by Diaporthe eres in China.

Hardy kiwifruit (Actinidia arguta), as an economically important fruit crop growing in Northeast China with thin, hairless and smooth skin, is susceptible to postharvest decay. In September 2018, infected cultivar Kwilv fruits were obtained from a commercial farm in Liaoning province, northeastern China. The occurring incidence of the rot disease varied from 20% to 90% according to the fruit number in each box during a 7-day-long storage at room temperature, and the initial symptom included a small, soft, chlorosis to light brown lesion and later watery brown lesions. Pure cultures of the same characteristics were obtained from the isolated strains in four rotten fruits on PDA medium. The isolates grew into transparent radial mycelium on PDA in the first two days followed by abundant white, fluffy aerial mycelium. After 14 days, colonies formed white to light brown aerial mycelial mats with gray concentric rings, and they produced gray and embedded pycnidia. Alpha conidia of 4.4 to 8.8 µm × 1.4 to 3.3 µm (n = 50) were abundant in culture, hyaline, aseptate, ellipsoidal to fusiform, while Beta conidia at 20.5 to 28.6 µm × 1.0 to 1.4 µm (n = 50) were hyaline, long, slender, curved to hamate. These morphological characteristics were similar to Diaporthe species (anamorph: Phomopsis spp.) (Udayanga et al. 2014). For identification, DNA was extracted from three single isolates respectively , and the internal transcribed spacer (ITS) region, β-tubulin (BT), and histone (HIS) H3 gene were amplified by using primers ITS1/ITS4 (White et al. 1990), T1/T22 (O'Donnell et al. 1997) and HIS1F/HISR (Gao et al. 2017), respectively. The three isolates produced identical sequences across all three gene regions, which were submitted to NCBI (Genbank accession numbers MT561361, MT561360 and MT855966). Nucleotide BLAST analysis revealed that the ITS sequence shared 99% homology with those of ex-type Diaporthe eres in NCBI GenBank (MG281047.1 and KJ210529.1), so did the BT sequence that had 98% identity to D. eres (MG281256.1 and KJ420799.1) and the HIS 99% identity to D. eres (MG28431.1 and MG281395.1) (Hosseini et al. 2020, Udayanga et al. 2014). Pathogenicity was tested by wound inoculation on the cv. Kwilv fruits. Five mature and healthy fruits were surface-sterilized with 1% NaClO solution, rinsed in sterile distilled water and dried. Every fruit was wounded by penetrate the peel 1-2 mm with a sterile needle, and inoculated with mycelium plugs (5 mm in diameter) of the isolate on PDA, with five inoculated with sterile PDA plugs as controls. Treated fruits were kept in sterilized transparent plastic cans separately under high humidity (RH 90 to 100%) at 28°C. After five days, the same rot symptoms were observed on all fruits inoculated with mycelium while the control remained symptomless. The fungi was re-isolated from the lesions of inoculated fruits and identified as D. eres by sequencing, thus fulfilling Koch's postulates. The pathogenicity experiment was re-performed using D. eres conidial suspension (107 conidia/ml) in sterile distilled water in October 2019 and the same results were obtained. D. eres was recently reported to cause European pear rot in Italy (Bertetti et al. 2018). To our knowledge, this is the first report of D. eres causing a postharvest rot in hardy kiwifruit in China, leading to severe disease and thus huge economic losses in Northeast China. Accordingly, effective measures should be taken to prevent its spreading to other production regions in China.

In Vitro Evaluation of Effect of Different Essential Oils in Management of Post-Harvest Fruit Rot of Banana (Musa Paradisiaca) Caused by Colletotrichum spp

A study was conducted to evaluate the in vitro efficacy of different essential oils in the management of post-harvest fruit rot of banana. It was carried out in completely randomized design (CRD) with three replications and six treatments at Nepal Plant Diseases and Agro Associates (NPDA). The each of six treatments: cinnamon oil (Cinnamomum verum), mustard oil (Brassica oleracea), castor oil (Ricinus communis), neem oil (Azadirachta indica), coconut oil (Cocos nucifera) and control were used at concentrations 200ppm, 500ppm and 1000ppm respectively. The radial growth of mycelium (mm) and percent growth inhibition (%) of Colletotrichum spp. was recorded. The decrease in the radial growth and increase in the percent growth inhibition was found in all the treatments except control as their concentration was increased, in which the lowest radial growth and the highest percent growth inhibition was found at 1000 ppm concentration. At 1000 ppm concentration, cinnamon oil shows the lowest radial growth and the highest percent growth inhibition (1.67mm and 98.15%) followed by mustard oil (54.00mm and 40.00%), neem oil (55.17mm and 38.70%), castor oil (55.83mm and 37.96%), coconut oil (61.17mm and 32.04%) and control (90mm and 0.00%) respectively.Thus, cinnamon oil is considered as a good essential oil in regards to a management of post-harvest disease of banana. Int. J. Appl. Sci. Biotechnol. Vol 9(3): 187-192.

First Report of Lasiodiplodia theobromae Causing Postharvest Fruit Rot on Guava (Psidium guajava) in Malaysia.

Guava (Psidium guajava L.) is an economically important tropical fruit crop and is cultivated extensively in Malaysia. In September and October 2019, postharvest fruit rot symptoms were observed on 30% to 40% of guava fruit cv. Kampuchea in fruit markets of Puchong and Ipoh cities in the states of Selangor and Perak, Malaysia. Initial symptoms appeared as brown, irregular, water-soaked lesions on the upper portion of the fruit where it was attached to the peduncle. Subsequently, lesions then progressed to cover the whole fruit (Fig.1A). Lesions were covered with an abundance of black pycnidia and grayish mycelium. Ten symptomatic guava fruit were randomly collected from two local markets for our investigation. For fungal isolation, small fragments (5×5 mm) were excised from the lesion margin, surface sterilized with 0.5% NaOCl for 2 min, rinsed three times with sterile distilled water, placed on potato dextrose agar (PDA) and incubated at 25 °C with 12-h photoperiod for 2-3 days. Eight single-spore isolates with similar morphological characteristics were obtained and two representative isolates (P8 and S9) were characterized in depth. Colonies on PDA were initially composed of grayish-white aerial mycelium, but turned dark-gray after 7 days (Fig. 1B). Abundant black pycnidia were observed after incubation for 4 weeks. Immature conidia were hyaline, aseptate, ellipsoid, thick-walled, and mature conidia becoming dark brown and 1-septate with longitudinal striations, 25.0 - 27.0 ± 2.5 × 13.0 - 14.0 ± 1.0 μm (n = 30) (Fig.1C, D). On the basis of morphology, both representative isolates were identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (Alves et al. 2008). For molecular identification, genomic DNA of the two isolates was extracted using the DNeasy plant mini kit (Qiagen, USA). The internal transcribed spacer (ITS) region of rDNA and translation elongation factor 1-alpha (EF1-α) genes were amplified using ITS5/ITS4 and EF1-728F/EF1-986R primer set, respectively (White et al. 1990, Carbone and Kohn 1999). BLASTn analysis of the resulting ITS and EF1-α sequences indicated 100% identity to L. theobromae ex-type strain CBS 164.96 (GenBank accession nos: AY640255 and AY640258, respectively) (Phillips et al. 2013). The ITS (MW380428, MW380429) and EF1-α (MW387153, MW387154) sequences were deposited in GenBank. Phylogenetic analysis using the maximum likelihood based on the combined ITS-TEF sequences indicated that the isolates formed a strongly supported clade (100% bootstrap value) to the related L. theobromae (Kumar et al. 2016) (Fig.2). A pathogenicity test of two isolates was conducted on six healthy detached guava fruits per isolate. The fruit were surface sterilized using 70% ethanol and rinsed twice with sterile water prior inoculation. The fruit were wound-inoculated using a sterile needle according to the method of de Oliveira et al. (2014) and five-mm-diameter mycelial agar plugs from 7-days-old PDA culture of the isolates were placed onto the wounds. Six additional fruit were wound inoculated using sterile 5-mm-diameter PDA agar plugs to serve as controls. Inoculated fruit were placed in sterilized plastic container and incubated in a growth chamber at 25 ± 1 °C, 90% relative humidity with a photoperiod of 12-h. The experiment was conducted twice. Five days after inoculation, symptoms as described above developed on the inoculated sites and caused a fruit rot, while control treatment remained asymptomatic. L. theobromae was reisolated from all symptomatic tissues and confirmed by morphological characteristics and confirmed by PCR using ITS region. L. theobromae has recently been reported to cause fruit rot on rockmelon in Thailand (Suwannarach et al. 2020). To our knowledge, this is the first report of L. theobromae causing postharvest fruit rot on guava in Malaysia. The occurrence of this disease needs to be monitored as this disease can reduce the marketable yield of guava. Preventive strategies need to be developed in the field to reduce postharvest losses.

Fungal pathogens associated with pre‐ And postharvest fruit rots of mango in southern Iran

AbstractThis study aimed at identifying fungal pathogens causing pre‐ and postharvest fruit rots on local cultivars of mango (Mangifera indica L.) in the main mango‐growing regions of southern Iran. Mango fruits showing rot symptoms from commercial orchards were used for isolation of fungal species associated with preharvest fruit rots. Latent infections were assessed on intact healthy mango fruits which were surface‐disinfested and incubated in moist chambers at 25ºC. For evaluation of postharvest wound infections, intact healthy mango fruits were artificially wounded and incubated in moist chambers at 25ºC. In addition, fungal decays were assessed on intact healthy mango fruits stored at 13ºC for up to 4 weeks. Isolated fungi were identified based on morphological characteristics, as well as sequence data from the ribosomal internal transcribed spacer (ITS) region. In addition, the sequence data inferred from translation elongation factor 1‐alpha (tef1) gene were used for determination of Fusarium species and Alternaria and Colletotrichum isolates were defined genetically based on multi‐gene sequencing. Accordingly, eight fungal species, including Alternaria alternata, Neofussicoccum mediterraneum, Aureobasidium melanogenum, Colletotrichum gloeosporioides, Fusarium proliferatum, Xenoacremonium falcatus, F. verticillioides and Diaporthe phyllanthicola, were identified to associate with preharvest mango fruit rots. Fungi associated with latent infections, mostly stem‐end rots, included A. alternata, N. mediterraneum, C. gloeosporioides, Lasiodiplodia theobromae, F. proliferatum and A. melanogenum, and those associated with wound infections were A. alternata, N. mediterraneum, Penicillium spp. and Cladosporium spp. A. alternata was the only pathogen isolated from the fruits stored at low temperature. Pathogenicity of the selected isolates was demonstrated by fulfilling Koch's postulates.

First record of Colletotrichum alienum Causing postharvest Anthracnose disease of mango fruit in China.

Mango (Mangifera indica L.) is one of the world's most significant economic fruit crops, and China is the second-largest producer of mango (Kuhn et al., 2017). Postharvest mango anthracnose is caused by Colletotrichum species and reduce the self-life of mature fruit (Wu et al., 2020). Colletotrichum species also cause postharvest anthracnose and fruit rot disease of Apple, Banana and Avocado (Khodadadi et al., 2020; Vieira et al., 2017; Sharma et al., 2017). In July 2019, mango fruits cv. 'Jin-Hwang' were observed at different fruit markets (39°48'42.1"N 116°20'17.0"E) of the Fengtai district, Beijing, China, exhibiting typical symptoms of anthracnose including brown to black lesions in different size (≤ 2 cm) with identified border on the mango fruit surface. Later, the lesions were coalesced and extensively cover the surface area of the fruit. The lesions were also restricted to peel the fruit and pathogen invaded in the fruit pulp. About 30% of mango fruits were affected by anthracnose disease. The margins of lesions from infected mango fruits (n=56) were cut into 2 × 2 mm pieces, surface disinfected with NaClO (2% v/v) for 30 s, rinsed thrice with distilled water for 60s. These pieces were placed on PDA medium and incubated at 25°C for 7 days. Pure culture of fungal isolates was obtained by single spore isolation technique. Initially, the fungal colony was off white, and colony extended with time, turning light gray at the center. The morphological examination revealed that conidia were hyaline, oblong, and unicellular. The conidia were measured from 10 days old culture and dimensions varied from 13.3 to 15.8 µm in length and 4.6 to 6.1 µm in width. For molecular identification, a multi-locus sequence analysis; the Internal Transcribed Spacers (ITS) region, partial actin (ACT) gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene and chitin synthase (CHS-1) gene were amplified by using the primer sets ITS1/4 (White et al. 1990), ACT-512F/ACT-783R (Carbone and Kohn 1999), GDF1/GDR1 (Guerber et al. 2003) and CHS1-79F/CHS-1-354R (Carbone and Kohn 1999) respectively. The partial sequences of MTY21 were deposited to GenBank accessions (MT921666 (ITS), MT936119 (ACT), MT936120 (GAPDH) and MT936118 (CHS-1). All obtained sequences showed 100% similarity with reported sequences of Colletotrichum alienum ICMP.18691 with accessions numbers JX010217 (ITS), JX009580 (ACT), JX010018 (GAPDH) and JX009754 (CHS-1) which represented the isolate MTY21 identified as C. alienum by constructing Maximum Likelihood phylogenetic tree analysis using Mega X (Kumar et al., 2018). For the confirmation of Koch's postulates, the pathogenicity test was conducted on 36 fresh healthy mango fruits for each treatment. Fruits were punctured with the help of a sterilized needle to create 2mm2 wounds and inoculated with 10µL inoculum (107 spores/mL) of MTY21. Control mango fruits were inoculated with 10µL sterilized distilled water and incubated at 25 °C with 90% relative humidity. The lesions appeared at the point of inoculation and gradually spread on the fruit surface after 7 days post inoculation. The symptoms were similar to the symptoms on original fruit specimens. The re-isolated fungus was identified as C. alienum based on morphological and molecular analysis. Mango anthracnose disease caused by several Colletotrichum species has been reported previously on mango in China (Li et al., 2019). Liu et al. (2020) reported C. alienum as the causal organism of anthracnose disease on Aquilaria sinensis in China. C. alienum has been previously reported causing mango anthracnose disease in Mexico (Tovar-Pedraza et al., 2020) To our knowledge, this is the first report of C. alienum causing postharvest anthracnose of mango in China. The prevalence of C. alienum was 30% on mango fruit which reflects the importance of this pathogen as a potential problem of mango fruit in China.

First report of Penicillium olsonii causing postharvest fruit rot on tomato in Serbia.

Tomato (Solanum lycopersicum, L.) is one of the most important vegetable crop in Serbia, with a total production of 111,639 t in 2019 (Statistical Office of the Republic of Serbia). In July 2020, six tomatoes (cv. Balkan) with symptoms of fruit rot were collected from market in Belgrade, Serbia. The incidence of disease was about 2%, and the symptomatic samples were stored for 10 days after harvest. The initial symptoms on fruits were small circular, slightly sunken and water-soaked spots with white mycelia, that progressively expanded into larger grey lesions following the occurrence of sporulation. Isolations were conducted from one spot/fruit. Small pieces (2 to 3 mm2) from the margins of lesions were surface sterilized for 1 min in 1% NaOCl, washed twice with sterile distilled water, and cultivated on potato dextrose agar (PDA) at 25°C. The isolation frequency of Penicillium-like colonies was 100%. In total, six monosporic isolates were obtained and two isolates (SZ-20-6 and SZ-20-7) were selected as representative for morphological and molecular identification, and pathogenicity test. Morphological characteristics of both isolates were observed after growth on malt extract agar (MEA) for 7 days at 25ºC. On MEA, mycelia were white and colonies turned greyish-green with abundant sporulation. On the reverse sides colonies were pale yellow. The mean colony diameter on MEA for isolate SZ-20-6 was 25 ± 1.2 mm and 26 ± 1.0 mm for isolate SZ-20-7. The colony texture was velvety, without exudates and pigmentation. The conidiophores of both isolates were terverticillate, unbranched; phialides were flask shaped with a short neck, and conidia were smooth, greenish and subglobose to ellipsoidal. The conidial diameter for isolate SZ-20-6 was 3 to 4 × 2.5 to 3 µm, and for isolate SZ-20-7 was 3.5 to 4 × 2.5 to 3.5 µm (n =50). Based on these characteristics, isolates were identified as Penicillium olsonii (Pitt 1979). To confirm the morphological identification, genomic DNA was extracted from isolates (SZ-20-6 and SZ-20-7), and the rDNA ITS region and partial β-tubulin gene (BenA) were amplified using the primers ITS1/ITS4 (White et al. 1990) and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. All sequences showed 99 to 100% similarity to P. olsonii and were deposited in GenBank (ITS, MW130235 and MW130236; BenA, MW145147 and MW145148). In multilocus phylogenetic analysis (ITS+BenA), isolates from this study clustered together with other P. olsonii sequences with 100% bootstrap support. To complete Koch's postulates, asymptomatic fruits of tomato cv. Balkan (five fruits per isolate) were superficially sterilized with 70% ethanol, wounded with a sterile needle and inoculated with 10 μl of a spore suspension (1 × 106 spores/ml). Five control fruits were inoculated with 10 μl of sterile distilled water. The experiment was repeated twice. After 7 days of incubation in a moisture chamber at 25°C, typical grey lesions developed on inoculated fruits. The control fruits remained symptomless. The isolates recovered from symptomatic fruits showed the same morphological features as the original isolates. P. olsonii was previously reported on tomato fruit only in Canada (Chatterton et al. 2012) and Pakistan (Anjum et al. 2018). To our knowledge, this is the first report of P. olsonii causing postharvest fruit rot on tomato in Serbia, and in Europe, as well. Therefore, it is essential to monitor spreading of P. olsonii on tomato and other crops in storages, and develop efficient disease management strategies.

First Report of Ceratocystis changhui Causing Postharvest Fruit Rot of Peach in Kunming, China.

The peach (Prunus persica (L) Batsch) is a predominant commercially grown stone fruit in China (Lee et al. 1990). Ceratocystis changhui is an aggressive pathogen causing typical black rot symptoms on corms of taro (Colocasia esculenta) (Liu et al. 2018), it has not been reported on other hosts. During the summer and autumn of 2013, a postharvest fruit rot disease was observed on several peaches at a farmer's market (N 25°02'; E 102°42') in Kunming City, Yunnan Province, China. The incidence of the disease varied from 5 to 20%. Necrotic spots were first observed on the infected peach fruit (Prunus persica cv. shuimitao). The spots enlarged gradually and developed into a brown, water-soaked and rotted lesion. Eventually, the whole fruit became soft, rotted and covered with a gray-brown mycelium (Fig. 1 A, B). The isolates were obtained from the symptomatic tissues incubated on slices of fresh carrot root (Moller et al. 1968). After 5 to 10 days of incubation, perithecia and mycelium were observed growing on carrot slices. Spore masses were removed from the apices of perithecia, transferred to potato dextrose agar medium (PDA) and incubated at 25°C for 5 to 10 days, followed by single-spore isolation. All eight single-spore isolates from peach fruits obtained in this study were deposited in the State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, China. In culture, mycelium was initially white, gradually turned to greyish-green or brown (Fig. 1E, F). Measurements were made 7 days after the formation of perithecia. Perithecia (Fig. 1G) were black, globose, 185.71 to 305.56 μm × 142.86 to 264.29 µm and showed a long black neck, 600 to 957.14 µm (Fig. 1H). Ascospores (Fig. 1I) were helmet-hat shaped and 2.86 to 6.67 µm ×3.81 to 4.76 µm. Cylindrical conidia (Fig. 1J) 6.67 to 38. 95 µm × 2.86 to7.62 µm were observed. Chlamydospore (Fig. 1K), 8.57 to 13.33 μm × 5.71 to 9.52 μm, were ovoid or obpyriform, smooth. To further verify pathogen identity the internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS1F and ITS4 (Thorpe et al. 2005), and the total genomic DNA from the mycelia of five isolates was extracted using a CTAB method (Lee &Taylor 1990). The nucleotide sequences have been blasted and deposited in the GenBank database. Analysis of the ITS sequences from the isolates T1-1yp, T1-2yp, T2-1yp (GenBank accession no. KY580895-KY580897) showed 99% to 100% similarity with isolates C. changhui CMW43272 (KY643886), CMW43281 (KY643884), CMW46112 (KY643891) and CMW46113 (KY643892) from taro in China. Phylogenetic trees based on the maximum-likelihood (ML) method were constructed using MEGA 7. ITS sequences of other Ceratocystis spp. were attained from NCBI for comparative analysis (Liu et al. 2018), and Davidsoniella virescens (CMW11164) served as outgroup. The robustness of ML tree was evaluated with 1,000 bootstrap (BS) values. The pathogen was identified as C. changhui based on the phylogenetic analysis (Fig. 2). Three isolates (T1-1yp, T1-2yp, T2-1yp) were used for pathogenicity. Nine Prunus persica cv. yingzuitao fruits at early maturity (8 points out of 10) were wound inoculated with 200μL conidia suspension of the fungus (approximately 2.0 × 106 conidia / mL). Degreasing cotton dipped in sterile water was used to raise the humidity in preservation boxes. Boxes were incubated for 10 days at 25°C. Three peaches as controls were treated only with sterile distilled water in the same way. Symptoms of sunken lesions and fruit rot were observed two days after inoculation, and measured at 1.8 to 3.2 cm from the inoculation point within 5 days (Fig. 1C: right, D). The same pathogen was re-isolated from them confirming Koch's postulates. Control peaches remained symptomless. This fungus was morphologically and phylogenetically identified as C. changhui. To our knowledge, this is the first report of C. changhui on postharvest peach in Yunnan, China. The disease will affect quality and taste of peach, so it is critical to deploy appropriate management strategies to limit the fungus spread.

Meyerozyma guilliermondii SQUCC-33Y suppresses postharvest fruit rot of strawberry caused by Alternaria alternata

Strawberry fruits are vulnerable to infection by a broad range of fungal pathogens before and after harvest. In this study, Alternaria spp. strains associated with fruit rot of strawberry were isolated and characterized and the potential of the antagonistic yeast Meyerozyma guilliermondii strain SQUCC-33Y for the control of fruit rot of strawberry was evaluated. A total of seven isolates of Alternaria (STR2-STR8) were isolated from strawberry fruits showing symptoms of rot. On the basis of internal transcribed spacer (ITS) ribosomal RNA (rRNA) sequences, these fungal isolates were identified as Alternaria alternata. Pathogenicity tests revealed that most of the strains of A. alternata were pathogenic to strawberry. The measurement of disease severity on strawberry fruits revealed significant differences in the virulence between A. alternata strains. M. guilliermondii restricted the growth of all the strains of A. alternata in dual culture assay. Postharvest treatment of strawberry fruits with M. guilliermondii significantly reduced the fruit rot lesion size caused by A. alternata. This antagonistic yeast has the potential for use as a biofungicide for the control of A. alternata-induced postharvest fruit rot of strawberry.

In vitro tolerance to antifungal glycoalkaloids and biofilm forming ability of the antagonistic yeast Meyerozyma guilliermondii strain SQUCC-33Y

Meyerozyma guilliermondii strain SQUCC-33Y is an antagonistic yeast against Alternaria alternata, the tomato fruit rot pathogen. In a previous study, we demonstrated the potential of M. guilliermondii SQUCC-33Y in the control of A. alternata-induced postharvest fruit rot of tomato. In this study, M. guilliermondii SQUCC-33Y was evaluated for its ability to tolerate antifungal glycoalkaloids of tomato and to form biofilm under in vitro conditions. Glycoalkaloids were extracted from immature green tomato fruits. Electrospray ionization-mass spectrometry (ESI-MS) analysis showed the presence of α-tomatine, β-tomatine, tomatidine, lycoperoside A, lycoperoside H, coumaric acid and sinapic acid in the glycoalkaloids extract. In vitro antifungal assays showed that M. guilliermondii SQUCC-33Y and A. alternata were tolerant to glycoalkaloids of tomato, while Rhizoctonia solani was sensitive. M. guilliermondii SQUCC-33Y was able to form biofilm as determined by in vitro microtiter plate assay.

Trichoderma asperellum T76-14 Released Volatile Organic Compounds against Postharvest Fruit Rot in Muskmelons (Cucumis melo) Caused by Fusarium incarnatum.

Postharvest fruit rot caused by Fusarium incarnatum is a destructive postharvest disease of muskmelon (Cucumis melo). Biocontrol by antagonistic microorganisms is considered an alternative to synthetic fungicide application. The aim of this study was to investigate the mechanisms of action involved in the biocontrol of postharvest fruit rot in muskmelons by Trichoderma species. Seven Trichoderma spp. isolates were selected for in vitro testing against F. incarnatum in potato dextrose agar (PDA) by dual culture assay. In other relevant works, Trichoderma asperellum T76-14 showed a significantly higher percentage of inhibition (81%) than other isolates. Through the sealed plate method, volatile organic compounds (VOCs) emitted from T. asperellum T76-14 proved effective at inhibiting the fungal growth of F. incarnatum by 62.5%. Solid-phase microextraction GC/MS analysis revealed several VOCs emitted from T. asperellum T76-14, whereas the dominant compound was tentatively identified as phenylethyl alcohol (PEA). We have tested commercial volatile (PEA) against in vitro growth of F. incarnatum; the result showed PEA at a concentration of 1.5 mg mL−1 suppressed fungal growth with 56% inhibition. Both VOCs and PEA caused abnormal changes in the fungal mycelia. In vivo testing showed that the lesion size of muskmelons exposed to VOCs from T. asperellum T76-14 was significantly smaller than that of the control. Muskmelons exposed to VOCs from T. asperellum T76-14 showed no fruit rot after incubation at seven days compared to fruit rot in the control. This study demonstrated the ability of T. asperellum T76-14 to produce volatile antifungal compounds, showing that it can be a major mechanism involved in and responsible for the successful inhibition of F. incarnatum and control of postharvest fruit rot in muskmelons.

First report of Diaporthe paranensis causing peach fruit rot

First report of Diaporthe paranensis causing peach fruit rot Andrea Dantas de Souza; Simone Mieko Yamamoto; Edlayne Gonçalez, Ricardo Harakava Abstract The production of peaches in Brazil is concentrated in the states of Rio Grande do Sul and São Paulo.Peachis a fruit rich in sugars and water, and these characteristics, combined with wounds in the harvesting and post-harvest stages, are determinants of shelf life of the fruit. Several fungi were isolatedfrom peaches with rot spots obtained at the central fruit and vegetables distribution center of São Paulo (CEAGESP). Fungal identification was performed by sequencing of the ITS region genes. Twenty isolates were identified as Monilinia fructicola, two as Botrytis cinerea, and two as Diaporthe spp. (D. cf. heveae and D. paranensis), the last two never before reported as causing postharvest rot in any fruit. Pathogenicity of D. paranensis was confirmed by observation of rot symptoms on inoculated peach fruits, reisolation and molecular identification of the fungus. This is the first report of D. paranensis causing postharvest peach fruit rot. Full Text: PDF DOI: 10.15640/jaes.v10n1a1

First report of a postharvest fruit rot in apple caused by Athelia sp. in Brazil

First report of a postharvest fruit rot in apple caused by Athelia sp. in Brazil

Development of eco-friendly nanoemulsions of some natural oils and evaluating of its efficiency against postharvest fruit rot fungi of cucumber

There are growing concerns about the extensive use of synthetic fungicides worldwide due to their negative health effect on humans, ecosystem, and the development of fungal resistance. Therefore, developing new and safe eco-friendly antifungal agents such as plant-based oils is of major interest. This study was conducted for the first time to develop and evaluate the efficiency of eco-friendly nanoemulsions of some natural oils and evaluating of its efficiency against postharvest fruit rot of cucumber caused by the following fungal isolates: Galactomyces candidum (MF373433), Alternaria tenuissima (MF 373440) and Fusarium solani (MF373443). Nanoemulsions of clove, black seed, lemon, and orange oils were formulated by using ultrasound and subjected to physicochemical and stability studies. The efficiency of these nanoemulsions was evaluated against the postharvest fruit rot fungi of cucumber. The oils of promising nanoemulsions have been analyzed by gas chromatography-mass spectrometry analysis (GC/MS). The acute toxicity study was conducted on rats and on the luminescence emitted of Vibrio fischeri bacteriausing Microtox®. The smaller droplet size of nanoemulsions was found after 10 min of sonication with an oil to Tween 80 ratio of 1:1 and 1:2 for clove and black seed oils, respectively. Nanoemulsion of black seed and clove oils from Egypt at 5000 ppm showed a significantly high reduction in the linear mycelial growth of fungal isolates. The mixture formula (2:1 v/v) of nanoemulsions of clove and black seed oils showed a significantly high reduction in linear mycelial growth, completely inhibited (100%) conidia sporulation of fungal isolates, and highly reduced the percentage of the rot of germinated seeds as well mortality of cucumber developed seedlings. Nanoemulsion formulation of clove and black seed (2:1) at concentration 2.0 % as soaking treatment of cucumber fruits before artificial infestation by inocula of fungal pathogens caused completely (100%) suppress postharvest fruit rot of cucumber. Both clove and black seed oils nanoemulsions and their combination showed no signs of toxicity or mortality in rats and no toxic effects on the luminescence emitted of Vibrio fischeri bacteria using Microtox® assay. Therefore, it can be concluded that the nanoformulation of clove and black seed oils at the ratio of 2:1 is a promising green and safe alternative to synthetic fungicide for application against postharvest rot of cucumber fruits.