Fusarium Fruit Rot Research Articles

A Diagnostic Guide for Fusarium Fruit Rot of Pumpkin and Winter Squash

Fusarium fruit rot caused by Fusarium solani f. sp. cucurbitae is an important postharvest disease impacting the global production and storage of pumpkins and winter squash ( Cucurbita spp.). The pathogen infects fruit through wounds, causing water-soaked lesions that may become sunken, coalesce, and be covered by fine mycelial growth. F. solani is soilborne and can survive long term in soil and plant debris. Storage rots impact several Cucurbita spp. grown for long-term storage. F. solani f. sp. cucurbitae has two races and is the most commonly found Fusarium species infecting cucurbits. Identification includes morphologic and PCR-based methods. This guide outlines taxonomy, symptoms, isolation, and epidemiology and provides methods to identify the pathogen.

First Report of Fruit Rot Disease on melon (Cucumis melo L.) Caused by Fusarium ipomoeae in China.

Fusarium rot on melon fruit has become an important postharvest disease for producers worldwide, typically involving multiple Fusarium pathogens (Khuna et al. 2022; Medeiros Araújo et al. 2021). In 2022, Fusarium fruit rot of muskmelon (Cucumis melo var. conomon) occurred sporadically in a field at Huainan Academy of Agricultural Sciences (32.658193º N, 117.064922º E) with an incidence of about 10%. Among these diseased muskmelons, a fruit exhibiting a white to yellowish colony athe intersection of the diseased and healthy tissues was collected and labeled TGGF22-17. The streak plate method was employed to isolate fungal spores on Bengal Red PDA (potato dextrose agar), which were then incubated at 25℃ in darkness. Following isolation and purification, a single-spore strain, TGGF22-17, was obtained and analyzed using morphological characters on PDA, synthetic nutrient agar (SNA) and carnation leaf agar (CLA) (Leslie and Summerell 2006), along with molecular identification. Colours were rated according to the color charts of Kornerup and Wanscher (1978). Based on the colony morphology on PDA, the isolate displayed a rosy buff or buff color with a white to buff margin. The colony margin was undulate, with the reverse transitioning from amber-yellow to honey-yellow. Aerial macroconidia on SNA were thin-walled, hyaline, mostly 3-5 septate, falcate, and measured 18.5-46.4 (x̄=34.2) × 2.9-4.8 (x̄ =3.9) μm in size (n =50). Sporodochial macroconidia on CLA were mostly five-septate with long apical and basal cells, exhibiting dorsiventral curvature. They were hyaline, with the apical cell hooked to tapering and the basal cell foot-shaped, measuring 46.5-89.6 (x̄ =72.3) × 3.5-5.0 (x̄ =4.3) μm in size (n = 100). Portions of three loci (TEF-1α, RPB1 and RPB2) were amplified and sequenced as described by Wang et al. (2019). Sequences were deposited in GenBank with accession number PP196583 to PP196585. The three gene sequences (TEF-1α, RPB1 and RPB2) of strain TGGF2022-17 shared 99.5% (629/632bp), 97.9% (1508/1540 bp) and 99.9% (1608/1609 bp) identity to the ex-type strain F. ipomoeae LC12165 respectively by pairwise DNA alignments on the FUSARIOID-ID database (https://www.fusarium.org). Phylogenetic analysis of the partial TEF-1α and RPB2 sequences with PhyloSuite (Zhang et al. 2020) showed the isolated fungus clustered with F. ipomoeae. Based on the morphological and phylogenetic analyses, TGGF22-17 was identified as F. ipomoeae. Pathogenicity tests were performed on healthy melons, which were surface-sterilized with 75% alcohol and wounded using a sterilized inoculation needle. A 4-mm diameter plug from a 7-day-old SNA culture of TGGF22-17 was aseptically inserted in the middle of the wound, sealed with plastic bag after absorbent cotton was included to maintain moisture. Five melons were each inoculated at three points. Noncolonized PDA agar plugs served as the negative control. The inoculated and uninoculated plugs were removed approximately 48 hours after inoculation. The melon inoculated with TGGF22-17 exhibited water-soaked black lesions 48h post-inoculation, resulting in a 100% infection rate (15/15). After 7 days, mycelium was obseved on the inoculated melons. No disease symptoms were observed on the uninoculated melons. To fulfill Koch's postulates, fungi were isolated from the inoculated fruit and confirmed as F. ipomoeae by morphological observation. Fusarium ipomoeae has been reported to cause fruit rot on winter squash (Cucurbita maxima) in Japan (Kitabayashi et al. 2023). To our knowledge, this is the first report of fruit rot on muskmelon caused by F. ipomoeae in China and this report will be valuable for monitoring and management of fruit rot disease on muskmelons.

Management of Fusarium fruit rot of Luffa cylindrical caused by Fusarium incarnatum and Fusarium chlamydosporum

Fusarium rot of Luffa cylindrical was detected at Kafr-El-Dawar province, Beheira governorate, North Egypt during the growing season 2021. Surveyed disease incidence at Beheira, Kafr El-Shekh and Sharkia governorate showed fruit rot incidences of 18.33%, 16.12%, and 12.42%, respectively. Two fungal isolates of Fusarium spp. were tested for their pathogenic ability to induce Fusarium rot disease and typical disease symptoms. The online Basic Local Alignment Search Tool for Nucleotide Sequences (BLASTN) was used for identification and confirmation of identity performance of Internal Transcribed Spacer (ITS) and DNA sequencing, then compared with sequences available in GenBank. The two fungal isolates were identified as Fusarium incarnatum and Fusarium chlamydosporum and registered under accession number MN480497 and MN480498, respectively. Under laboratory conditions, organic acids, essential oils and organic salts significantly inhibited the growth of the two fungal isolates. Complete inhibition of fungal growth (100%) was recorded at 0.75 g/l of Topsin-M70 (Thiophanate-methyl) and 0.5% of salicylic acid. Meanwhile, a moderate growth reduction was observed using benzoic acid, coumarine, and cinnamon, thyme oil and garlic oil treatments. Under field conditions for two successive seasons, similar trends were observed. Foliar sprays with the fungicide Topsin-M70 showed the largest reduction in disease expression. The highest fruit rot disease reduction was recorded for salicylic acid and coumarin treatments followed by thyme oil, benzoic acid and potassium carbonate, garlic oil, boric acid and sodium bicarbonate. We concluded that the treatments are effective, safe and cost-effective methods for the control of this pre-harvest fruit disease under field conditions.

Effect of green Fe2O3 nanoparticles in controlling Fusarium fruit rot disease of loquat in Pakistan.

The subtropical fruit known as the loquat is prized for both its flavour and its health benefits. The perishable nature of loquat makes it vulnerable to several biotic and abiotic stressors. During the previous growing season (March-April 2021), loquat in Islamabad showed signs of fruit rot. Loquat fruits bearing fruit rot symptoms were collected, and the pathogen that was causing the disease isolated and identified using its morphology, microscopic visualisation, and rRNA sequence. The pathogen that was isolated was identified as Fusarium oxysporum. Green synthesized metallic iron oxide nanoparticles (Fe2O3 NPs) were employed to treat fruit rot disease. Iron oxide nanoparticles were synthesized using a leaf extract of the Calotropis procera. Characterization of NPs was performed by different modern techniques. Fourier transform infrared spectroscopy (FTIR) determined the existence of stabilizing and reducing compounds like phenol, carbonyl compounds, and nitro compounds, on the surface of Fe2O3 NPs. X-ray diffraction (XRD) explained the crystalline nature and average size (~49 nm) of Fe2O3 NPs. Energy dispersive X-ray (EDX) exhibited Fe and O peaks, and scanning electron microscopy (SEM) confirmed the smaller size and spherical shape of Fe2O3 NPs. Following both in vitro and in vivo approaches, the antifungal potential of Fe2O3 NPs was determined, at different concentrations. The results of both in vitro and in vivo analyses depicted that the maximum fungal growth inhibition was observed at concentration of 1.0 mg/mL of Fe2O3 NPs. Successful mycelial growth inhibition and significantly reduced disease incidence suggest the future application of Fe2O3 NPs as bio fungicides to control fruit rot disease of loquat.

First report of Fusarium sporotrichioides causing Fusarium fruit rot on peaches in Pakistan.

Peach (Prunus persica) is an important stone fruit crop cultivated on 14,350 hectares in temperate areas of Pakistan, where post-harvest fungal rots cause major economic losses for growers. During April-August 2019, rotted peaches were observed in fruit markets of Rawalpindi district (33° 37' 33.8052'' N and 73° 4' 17.1912'' E), Punjab Province, Pakistan. Symptomatic fruit were surface sterilized for 3 min in 0.5% NaClO and 1 min in 70% ethanol, then rinsed three times in sterilized distilled water and air-dried for 30 minutes on filter paper. Tissue segments were excised from the margins of rot lesions and placed on potato dextrose agar (PDA), followed by incubation for one week at 25 +1o C. Furthermore, to maintain original sporodochial morphology and conidial description tissue segments were also grown on carnation leaf agar (CLA) and synthetic nutrient agar (SNA) (Sever et al., 2012). A total of 22 isolates were obtained from different fruit markets; colonies were fast-growing with pinkish-white, fluffy mycelia. Microconidia were abundant, 7.5 to 11.3 × 2.1 to 4.1 μm, oval to spindle-shaped, thin-walled, and hyaline whereas, macroconidia were thick-walled, sickle-shaped, 5- to 7-septate, hyaline, and 23.5 to 39.7 × 3.7 to 7.0 μm on carnation leaf agar. Virulence intensity of fungal isolates was confirmed after pathogenicity. Based on morphological characteristics, isolates were identified provisionally as Fusarium sporotrichioides (Leslie and Summerell 2006). For molecular identification, three target gene regions (ITS, elongation factor (EF), and β-tubulin benA) were amplified for highly pathogenic fungal isolates (FUS21K, FUS9SM, and FUS63KP) (O'Donnell et al. 2015). BLAST searches of the obtained sequences indicated 100% homology with GenBank accession number MN452643, and 99.56% homology with MT635298 for the ITS region, similarly 100% identity with GenBank accession numbers MN555016, MN555126, and MN555037 for the EF gene, and 100% homology with GenBank accession numbers MK435577, MH791363, and GQ915448 for β-tubulin benA of the F. sporotrichioides species complex (O'Donnell et al. 2015). Sequences were deposited in GenBank; accession numbers for each gene were as follows: ITS, ON180670, ON180671, and ON180672; EF, ON312093, ON312094, and ON312095; and β-tubulin benA, ON312090, ON312091, and ON312092. Maximum likelihood analysis on RPB1 and RPB2 nucleotide sequences of various fusaria was conducted which revealed that F. sporotrichioides formed a monophyletic relationship to terminal fusarium clade (TFC) comprising 22 strongly supported species complexes and 10 monotypic lineages, which were provisionally recognized as Fusarium. To complete Koch's postulates, 10μl aliquots of spore suspensions (106 spores/ml) of each FUS21K, FUS9SM and FUS63KP were pipetted individually onto six ripe, asymptomatic peaches. Sterile distilled water was applied as a negative control on four fruit. Fruit were incubated at 25 ± 1°C for one week in a sterile moist chamber, and the trial was conducted three times. Rot symptoms associated with pinkish-white fluffy mycelia were observed on inoculated fruits after 72 hours, whereas no mycelium was observed on the negative controls. The cultures on PDA, CLA and SNA from each of the inoculated fruit were morphologically identical to the original culture. The pathogen was confirmed as a member of F. sporotrichioides species complex based on pinkish-white mycelium, with red color on the underside of petri plates and the manner in which conidia are born on conidiophores. This is the first report of F. sporotrichioides on peaches from Pakistan, providing an important foundation for peach growers, agricultural advisers, plant pathologists, and plant breeders to improve the management of this economically damaging disease.

Aggressivity of Different Fusarium Species Causing Fruit Rot in Melons in Brazil

Brazil is one of the largest melon (Cucumis melo) producers in the world and most of the production is exported to international markets. Currently, over 15% of Brazilian melon shipments are lost during export transportation due to Fusarium fruit rot, which is jeopardizing the livelihood of Brazilian melon producers. We focused on understanding the aggressivity of five species of Fusarium causing fruit rot on the main types of melon produced in Brazil. We also investigated the correlation between pathogenicity and fruit quality. Experiments were performed under a completely randomized experimental design, in a 5 × 8 factorial scheme, using two methods for inoculation: deposition of discs of culture media containing fungal structures and deposition of spore suspensions in needle-punctured lesions. The fungal species used were Fusarium falciforme, F. sulawesiense, F. pernambucanum, F. kalimantanense, and Fusarium sp. Fruits of two hybrids from four types of melons, canary (Goldex and Gold Mine), piel de sapo (Grand Prix and Flecha Verde), galia (McLaren and DRG3228), and cantaloupe (SV1044MF and Bonsai), were used. Disease severity was assessed by measuring the lesions, disease severity index, fruit firmness, and degrees Brix of fruits. The five Fusarium species caused rot in the fruits of all melon hybrids studied and the aggressivity of those fungal species varied with the type and hybrid. Fruits of the hybrids McLaren and Bonsai presented the largest lesions among all melon hybrids, and hybrids of canary type (Gold Mine and Goldex) were the most tolerant to rot caused by the Fusarium species investigated. Furthermore, the greater the severity of Fusarium fruit rot, the lower the pulp firmness of the fruits, but degrees Brix did not correlate with the onset of the disease.

Antifungal Activity of Aqueous Plant Extracts and Effects on Morphological and Germination of Fusarium Fruit Rot Pathogens

Fusarium fruit rot caused by fusarium species pathogens can be considered a threat to economic loss. The use of synthetic antifungals to control the pathogens has failed to the development of resistance of pathogens. Previous studies reported that plant extracts may contain various bioactive constituents that are able to control pathogen growth. Hence, the aims of this study are to examine the inhibition activity of some plant fresh extracts on mycelial growth and morphological changes of Fusarium oxysporum, F. proliferatum, and f. solani, causal agents of Fusarium fruit rot. Aqueous extract of selected plants was evaluated for their inhibition activity against all the three fusarium pathogens under in vitro condition using poisoned food bioassay. Averrhoa bilimbi fruit extract demonstrated a highly significant effect against mycelial growth of the pathogens with fungal inhibition percentage of 80.51% for F. oxysporum, 61.28% for F. proliferatum and 58.97% for f. solani. The results showed that the highest formation of 100% extract has lowered the conidia concentration and germination percentage of F. oxysporum (35.43%), F. proliferatum (47.61%), and f. solani (38.67%) compared to the control. Significant shriveled mycelia were observed via scanning electron microscope (SEM) on the pathogens treated with a. bilimbi extract, indicating morphological changes occurred in the cell membrane compared to the control in which the mycelia were in normal form. This innovation, which can be prepared and applied at home, has the potential as an eco-friendly and a benign approach to control fruit rot pathogen.

Impact of Inoculation Methods and Fruit Maturity on Development of Fusarium Fruit Rot (Fusarium musae) Disease in Banana

Background: Fusarium fruit rot symptoms appear at all stages of banana fruit once infection initiates and progress from the stylar end as dark brown to black small spots which eventually turns black rotten areas leading to rotten pulp which renders the fruit unmarketable. Very meagre research work has been done on Fusarium fruit rot disease of banana in India and hence the present investigation on Fusarium fruit rot diseases of banana was undertaken south Gujarat condition. Methods: During the period 2018-2019 tested different inoculation methods were tested on the development of banana Fusarium fruit rot disease viz., stylar end pricking, rubbing, pricking at epicarp and without injury on banana fruit. Disease severity and incidence were recorded at 4th and 8th day after inoculation. In order to find out the most vulnerable stage of fruit for initiation of infection and development of Fusarium fruit rot disease, three stages of fruits were selected i.e., unripe, semi-ripe and ripe.Conclusion: Among, the different methods with fruit injury, stylar end pricking method was found best for the infection and development of Fusarium fruit rot (34.14%) after 8th days of inoculation followed by pricking at epicarp (27.79%). Further it was observed that injury of fruit surface is essential for infection and development of Fusarium fruit rot in banana. However, the severity of Fusarium fruit rot revealed that the highest severity was recorded in ripe fruits (30.21%) as compared to semi ripe (30.08%) and unripe (14.70%) fruits.

Evaluation of the Efficacy of Different Fungicides against Fusarium musae, a Fruit Rot Disease of Banana

Fruit rot disease caused by Fusarium musae is one of the post-harvest disease of banana and is adversely affecting the fruit quality and the market value In vitro evaluation of different fungicides, against F. musae. Amongst, fungicides viz., mancozeb 75 WP at 2500 ppm, azoxystrobin (20%) + difenoconazole (12.5%) at 1000 ppm and propiconazole (25 EC) at 500 ppm and 1000 ppm were found cent per cent inhibition of mycelial growth of F. musae. Whereas, in vivo evaluation were lowest fusarium fruit rot severity was observed in propiconazole (25 EC) at 1000 ppm in pre (6.61%) and post- inoculation (6.70%) treatments at 8 days after inoculation.

The Potency Purple Sweet Potato (Ipomoea batatas) Leaf Extract as Biofungicide for Controlling Fusarium Rot on Chili

Fusarium sp. has been recognized as a pathogenic agent causing fruit rot in chili. The disease significantly decreases the annual chili production rate. One of the plants potentially utilized as biofungicide to control Fusarium fruit rot disease in chili is purple sweet potato (Ipomoea batatas L.). Purple sweet po-tato contains secondary metabolites, mainly the active compounds in the form of flavonoids, which has been previously revealed to perform antifungal activity. This study aimed to examine the potential of purple sweet potato (Ipomoea batatas L.) leaf extract as biofungicide to inhibit the growth of chili rot disease caused by Fusarium sp. within vitro and in vivo assay. This work was conducted by testing the ethanol-extracted purple sweet potato leaves extracts against Fusarium sp. with various concentrations, i.e., 5%, 10%, 20%, and 40% (w/v) for in vitro assay. Then antifungal test against Fusarium sp. was conducted using preventive and curative test for in vivo assay. Observa-tions were performed for 7 days. The result of in vitro assay showed inhibi-tory ability of the leaves extract against the growth of Fusarium sp. to range between 35.2-76.6% with potential concentration 40% (w/v). Based on the results of in vivo assay, the preventive test using 40% concentration of purple sweet potato leaves extract showed significant different against negative con-trol through Duncan test (α = 0.05). Purple sweet potato leaves extract with 40% concentration can reduce the intensity of Fusarium fruit rot disease and potentially utilized as biofungicide.

Effect of hot water treatments on apple fruit rot caused by Fusarium spp.

Hot water treatments of apple fruits prior to long-term storage have a high potential as a physical measure against apple fruit storage rot caused by plant pathogenic fungi. Fusarium species are increasingly found as causal agents of postharvest apple fruit rot. The effect of high temperatures on casual agents of Fusarium fruit rot, F. avenaceum and F. graminearum, was tested in this article. In in vitro assay, spore suspensions of F. avenaceum and F. graminearum were exposed to high temperatures (ranging from 45 to 90 °C) at different duration (ranging from 30 s to 20 min) and the treatments that significantly inhibited mycelial growth of the isolates (53 and 57 °C for 3 and 5 min) were tested in vivo by hot water treatment of inoculated apple fruits of Fuji cultivar. The obtained results showed that the most promising hot water treatment should be between 53 and 57 °C and between 3 and 5 min of the exposure period.

Potensi Ekstrak Kangkung sebagai Biofungisida untuk Mengendalikan Penyakit Busuk Buah Fusarium pada Tomat

One of the important pathogens on tomato is Fusarium sp . causing wilt and fruit rot. This study aims to investigate the potency of water spinach ( Ipomea aquatica ) as a biofungicide for inhibiting growth and development of tomato fruit rot caused by Fusarium sp . This study showed inhibiting ability of I. aquatica stem extract to Fusarium sp . growth ranges from 3.40% to 8.67%, while inhibiting ability of leaves extract can reach 3.40% to 45.55%. Resistance induction test showed that in vitro treatment of I. aquatica leaves extract 20% can lengthen incubation time of Fusarium fruit rot compared to positive and negative control. Leaves extract of I. aquatica 20% is potential as biofungicide. Key words: biofungicide, Fusarium sp ., Ipomea aquatica

First Report of Fusarium proliferatum Infecting Pimento Chili Peppers in Trinidad.

In Trinidad, pimento chili peppers (Capsicum annuum L.) are grown for large domestic and regional export markets. Production is intensive during the rainy season (June to December). In August 2010, pimento fruits with symptoms of fruit rot were collected from fields located in Tableland, Valencia, Aranguez-North and -South, and Macoya. Symptoms began as a discoloration and soft rot of the peduncle and calyx (green to brown then black); a tan, watery lesion (with irregular margins) developed and expanded rapidly from the calyx down the sides of the fruit with internal rot of the placenta. Excessive fruit drop was also common. Estimated yield loss was ~20 to 60% for each field. Symptoms were observed on green and red fruits. Fruits were surface disinfected (2 min in 70% ethanol, 2 min in 0.5% NaOCl, followed by three rinses with sterile distilled water) and then a 4-mm3 block of tissue was taken from the lesion edge and placed on water agar. After 7 days at 25 ± 1°C, a 4-mm3 block of agar that contained the advancing hyphal edge of each colony was transferred to selective fusarium agar (3) and incubated as previously described. Colonies were fast growing with white, fluffy, aerial mycelia; hyphae densely branched; polyphialides abundant; microconidia abundant, thin walled, hyaline, ovoid, aseptate or 1-celled, and 5.5 to 12.2 × 2.0 to 3.2 μm. Macroconidia were moderately curved to straight, hyaline, 3- to 4-celled, thick walled, and 20.5 to 35.0 × 3.5 to 5.0 μm. Molecular characterization was based on a two-loci approach. PCR amplification was carried out with universal primers (ITS4/5) and translation elongation factor primers (EF1/2) (2). Sequences of the ITS1-5.8S-ITS2 region of rDNA (GenBank Accession No. HQ333547) and partial EF-1α gene (GenBank Accession No. HQ333548) were compared to cognate sequences available in GenBank and the FUSARIUM-ID databases (2). Comparisons revealed 100% similarity to Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg 1982. F. proliferatum (synonym Gibberella intermedia) is the anamorphic form of the G. fujikuroi complex that belongs to the Nectriaceae family (4). Pathogenicity tests were conducted by dispensing 10 μl of a prepared spore suspension (106 spores/ml) onto nonwounded and wounded sites of pimento fruits (landrace 'Trinidad seasoning', 10 fruits per isolate, 8 isolates). Negative controls were fruits inoculated with sterile distilled water. Inoculated fruits were kept at 25 ± 1°C in partially sealed plastic containers and monitored for the onset of symptoms for 7 days. The test was conducted twice. Lesions, similar to those recorded on field infected fruit, developed on inoculated fruits that were wounded and nonwounded, but not on water controls. The pathogen was reisolated from infected tissues, thereby fulfilling Koch's postulates. F. proliferatum is associated with disease of a number of economically important crops and ornamental plants worldwide (1). Fusarium fruit rot of pepper has been shown to significantly reduce marketable yield and shelf life of infected fruits. To our knowledge, this is the first report of Fusarium fruit rot of pimento chili peppers caused by F. proliferatum in Trinidad.

Fall- and Spring-sown Cover Crop Mulches Affect Yield, Fruit Cleanliness, and Fusarium Fruit Rot Development in Pumpkin

In 2001 and 2002, fall- and spring-sown, spring-killed or spring-sown living cover crops mulches were evaluated for their effects on pumpkin (Cucurbita pepo) number and weight, fruit cleanliness, and fusarium fruit rot (FFR; Fusarium solani f. sp. cucurbitae race 1). In general, the number and weight of orange (mature) fruit and total fruit weight were higher in bare soil (conventional), fall- or spring-sown, spring-killed cover crop mulches compared with spring-sown, living annual medic (Medicago spp.) cover crop mulches. In both years, pumpkins grown on fall-sown winter rye (Secale cereale), hairy vetch (Vicia villosa), winter rye + hairy vetch, and spring-sown oat (Avena sativa) produced fruit numbers and weights comparable to or slightly higher than bare soil (conventional) production, suggesting that these cover crop mulches had no effects on reducing pumpkin yield. The number and weight of pumpkins grown in spring-sown, living annual medic cover crop mulches were reduced in both years compared with the other cover crop mulches. On artificially inoculated field plots, percentages of groundcover at harvest and fruit with FFR were 89% and 5% in fall-sown winter rye (seeded at 90 lb/acre), 88% and 10% in fall-sown rye (50 lb/acre), 85% and 5% in fall-sown rye + hairy vetch (50 lb/acre each), 19% and 30% in fall-sown hairy vetch (50 lb/acre), 23% and 23% in spring-sown oat (110 lb/acre), 1% and 25% to 39% in spring-sown, living annual medics (40 lb/acre) and 0% and 46% in bare soil plots, respectively. Results suggest that cover crop mulches such as fall-sown winter rye, fall-sown winter rye + hairy vetch, or spring-sown, spring-killed oat killed and left on the soil surface may help reduce losses to FFR in pumpkin production.

First Report of Fusarium solani Causing Fruit Rot of Sweet Pepper in Trinidad.

In Trinidad, sweet pepper (Capsicum annuum L.) is an important crop that is produced for local markets and regional export. From February to April 2010, severe fruit rot was observed in 9 of 11 commercial fields located in North Trinidad in the major production areas of North and South Aranguez. All fields were in the late harvesting stage and the most commonly grown cultivars were Aristotle and Canape. Disease incidence for each field was estimated to be 80% with a yield loss of 40 to 60%. Symptoms appeared on mature red fruits but growers reported that disease can also occur on green fruit. Symptoms began as soft lesions that turned dark brown to black. Lesions usually originated at the calyx end of the fruit and extended down the sides. Fruits were surface sterilized by rinsing with 70% ethanol for 2 min, followed by three rinses with sterile distilled water. Two 4-mm3 blocks of tissue from the opposite sides of fruit lesions were transferred to water agar and incubated for 5 to 7 days at 25 ± 1°C. A 4-mm3 agar block consisting of the leading mycelial edge was then transferred to potato dextrose agar (PDA) and incubated under the same conditions. Colonies on PDA were fast growing with white, fluffy, aerial mycelia; hyphae were septate and hyaline; conidiophores were unbranched; microconidia were abundant, thin walled, hyaline, ovoid, one to two celled, and measured 6 to 10 × 2 to 4 μm. Macroconidia were hyaline, three to four celled, curved, thick walled, and measured 20 to 30 × 4 to 6 μm. PCR amplification was carried out utilizing universal primers ITS4/5 and translation elongation factor primers EF1/2 (2). Sequence comparisons of the internal transcribed spacer (ITS) region (HM157262) and EF-1α gene (HQ014854) with cognate sequences available in GenBank and the FUSARIUM-ID databases revealed 100 and 99.6% sequence identity, respectively, to Fusarium solani (Mart.) Sacc. Pathogenicity tests were conducted by drop inoculating 10-μl of spore suspension (106 spores/ml) of each of four isolates on wounded and unwounded sites of mature sweet pepper fruits (five per isolate of cvs. Aristotle, Canape, Century, Destra, and Paladin). Control fruits were inoculated with sterile distilled water. Inoculated fruits were kept at 25 ± 1°C in loosely sealed plastic containers and monitored for the onset of symptoms for 6 days. The experiment was conducted twice. Lesions (8.0 to 15.2 mm in diameter) developed on wounded fruit of Aristotle, Canape, and Century. No symptoms were seen on Destra, Paladin, or the water controls. No symptoms developed on nonwounded fruits. Koch's postulates were fulfilled by reisolating the pathogen from infected tissues. Fruit rot caused by F. solani has been reported to be a serious constraint to sweet pepper production in Canada (4), the United Kingdom (1), and New Zealand (3). To our knowledge, this is the first report of Fusarium fruit rot of sweet pepper in Trinidad.

Survey of Fusarium spp. Associated with Fruit Rot of Pumpkin in Ohio

From 2000 to 2002 commercial pumpkin (Cucurbita pepo) fields in Ohio were surveyed for Fusarium fruit rot. From six counties in 2000, 2001, and 2002, a total of 43 isolates from eight farms, 84 isolates from nine farms, and 40 isolates from six farms were collected, respectively. Fusarium solani f. sp. cucurbitae race 1 was the most commonly isolated Fusarium species from infected pumpkin fruit in Ohio. Other Fusaria isolated from infected fruit included F. oxysporum, F. graminearum, and F. acuminatum. A survey of infected pumpkin fruit in the field and inoculation studies of mature, healthy pumpkin cultivar Magic Lantern in the laboratory resulted in three types of fruit rot symptoms. Type 1, caused by F. oxysporum and F. acuminatum, resulted in a slow-expanding rot just below the rind surface of the infected fruit. Type 2, caused by F. graminearum, resulted in an expanding, slightly sunken, irregular rot of the rind surface. Type 3, caused by F. solani resulted in expanding, circular sunken lesions on the fruit surface bearing white to tan sporodochia. This is the first report of F. solani f. sp. cucurbitae race 1, F. oxysporum, F. acuminatum, and F. graminearum causing fruit rot of pumpkin in Ohio. Accepted for publication 26 July 2010. Published 27 August 2010.

First Report of Fusarium solani Fruit Rot of Pumpkin (Cucurbita pepo) in Trinidad.

Trinidad is a major exporter of pumpkins (Cucurbita pepo L.) to other Caribbean countries, Canada, and the United States. Producers and exporters have reported 50 to 80% yield losses because of soft rot and overnight collapse of fruit at the pre- and postharvest stages. Severe fruit rot occurred in fields in Victoria County in South Trinidad between April and May 2006 (mid-to-late dry season) with an increase in the severity and number of affected fruit in the rainy season (July to December). Symptoms began as water-soaked lesions on the fruit of any age at the point of contact with the soil. The disease progressed to a soft rot with leakage and whole fruit collapse. A dark brown, soft decay also developed at the base of the main vines. Fusarium solani was isolated on selective fusarium agar and potato dextrose agar (PDA) (1) after 7 to 10 days of incubation at 25°C. The pathogen was identified by morphological characteristics and pathogenicity tests. Colonies were fast growing with white aerial mycelia and a cream color on the reverse side; hyphae were septate and hyaline, conidiophores were unbranched, and microconidia were abundant, thin walled, hyaline, fusiform to ovoid, generally one to two celled, and 8 to 10 × 2 to 4 μm. Macroconidia were hyaline, two to three celled, moderately curved, thick walled, and 25 to 30 × 4 to 6 μm. Pathogenicity tests for 10 isolates were conducted on 2-week-old pumpkin seedlings (cv. Jamaican squash; seven plants per isolate) and mature pumpkin fruit (2). Briefly, seedlings were inoculated by dipping their roots in a spore suspension (1 × 104 spores per ml) for 20 min. The plants were repotted in sterile potting soil. For negative controls, plant roots were dipped in sterile water. After the rind of fruit was swabbed with 70% ethanol followed by three rinses with sterile distilled water, 0.4-cm-diameter agar plugs of the isolates were inserted into wounds made with a sterile 1-cm-diameter borer. Sterile PDA plugs served as negative controls. Fruit were placed in sealed, clear, plastic bags. Inoculated plants and fruit were placed on greenhouse benches (30 to 32°C day and 25 to 27°C night temperatures) and monitored over a 30-day period. Tests were repeated once. Inoculated fruit developed a brown, spongy lesion that expanded from the initial wound site over a period of approximately 17 days after inoculation. White mycelia grew diffusely over the lesion. Inoculated plants developed yellow and finally necrotic leaves and lesions developed on stems at the soil line approximately 21 days after inoculation. No symptoms developed on the control plants. The fungus was reisolated from symptomatic tissue, fulfilling Koch's postulates. To my knowledge, this is the first report of Fusarium fruit rot of pumpkin in Trinidad.

Fusarium Fruit Rot of Greenhouse Sweet Peppers in Canada.

In the summer of 2001, a fruit rot of orange sweet peppers (Capsicum annum L. cv. Sympathy MZ) was observed in commercial greenhouses in British Columbia, Canada. According to the grower's estimate, approximately 40% of fruits in the commercial greenhouse were severely affected in the year 2001 and approximately 10% in 2002. The disease appeared on mature fruits at harvest time, and affected fruits are considered as culls. The disease appeared as discolored soft patches or necrotic spots predominantly at the calyx end and occasionally, anywhere on the mature fruit at harvest time. Seeds and the surrounding area inside the fruits were covered with fungal growth and orange-pink spore masses. Five fungal isolations were made from the lesions. Infected tissues from the edge of lesions were surface sterilized in 1% sodium hypochlorite for 2 min, blotted dry on sterile filter paper, and cultured on potato dextrose agar (PDA). Plates were incubated at 22°C for 7 days. Single spore fungal colonies isolated from the tissues yielded Fusarium sp. Only one fungal species was consistently isolated from affected pepper fruits. Morphology of the fungus was consistent with Fusarium subglutinans (Wollenweber & Reinking) Nelson et al. according to Keith Seifert of Eastern Cereal and Oilseed Research Centre, Ottawa, Canada. Molecular tests are being developed to confirm the identification of the fungus. To confirm pathogenicity, 10 flowers and developing fruits of sweet pepper cv. Sympathy MZ grown in a greenhouse were inoculated with the pathogen. For inoculation, 20 μl of spore suspension of the fungus (concentration 106 spores/ml) was drop-inoculated on the wounded and unwounded surfaces of fruits. To inoculate flowers, a spore suspension was drop-inoculated in the middle of flowers without any wounding. Controls were treated with 20 μl of sterile water. The experiment was repeated once. Approximately 80% of inoculated fruits and flowers developed symptoms on fruits similar to naturally infected fruits at maturity. Fruits from control plants did not develop any disease. On PDA, a Fusarium species identical to the original one was recovered from all inoculated infected fruits. A preliminary study showed that this pathogen does not infect other greenhouse crops such as tomato, cucumber, or lettuce. Sweet pepper stem and fruit rot caused by Fusarium solan has been reported previously (1) but there is no report of fruit rot caused by a Fusarium subglutinans-like species on greenhouse sweet peppers. Reference: (1) J. G. Menzies and W. R. Jarvis. Fusarium stem and fruit rot. Pages 333-334 in: Diseases and Pests of Vegetable Crops in Canada. R. J. Howard et al. eds. The Canadian Phytopathological Society and Entomological Society of Canada, 1994.

Fusarium Fruit Rot of Citrus in Jeju Island

Twenty-three isolates of Fusarium spp. were obtained from decayed citrus fruits in the fields and storages in 1998-1999. Of them, six and five isolates belonged to F. proliferation and F. moniliforme, respectively, which were the most common. F. solani and F. sambucinum had each two isolates, F. equiseti had one isolate and seven isolates were unidentified. They produced symptoms of two types in pathogenicity test: those with leathery, beige to light or dark brown, and sunken lesions without surface mycelium (type-1) and those with lesions covered with white, beige or pink surface mycelium (type-2). Four of six isolates identified to F. proliferation and two unidentified isolates produced type-1 lesions, and all isolates identified to F. moniliforme, F. solani, F. sambucinum, F. equiseti and five unidentified isolates produced type-2 lesions.

Fusarium Fruit Rot of Pumpkin in Connecticut

In 1992, an unusual array of symptoms was found in Connecticut exclusively on cultivar Howden pumpkins (Cucurbita pepo). The lesions decreased marketability of the pumpkins and were categorized as a preharvest dry, hard rot (type 1) or a postharvest soft, sunken rot (type 2). In decreasing frequency of isolation, Fusarium acuminatum, F. equiseti, and F. graminearum were isolated from type 1 lesions, and F. graminearum, F. equiseti, F. avenaceum, and F. solani were recovered from type 2 lesions. When isolates of each species were wound-inoculated into mature pumpkins representing 13 cultivars of C. pepo, they all produced type 2 lesions except F. acuminatum, which produced type 1 lesions. The cultivar Atlantic Giant (Cucurbita maxima) was resistant to colonization by all Fusarium spp. tested. There was no effective inhibition of hyphal growth or spore germination of F. acuminatum, F. equiseti, and F. graminearum from eight fungicides tested in vitro.