Leatherleaf Fern Research Articles

Identification of Pathogens Causing Important Diseases in Leatherleaf Fern (Rumohra adiantiformis) and In Vitro Inhibition using Bacillus velezensis B-27

Leatherleaf fern (<em>Rumohra adiantiformis</em>) is a famous ornamental-leaf plant that has been used by florist entrepreneurs around the world. It is one of the leading export commodities in Indonesia, however, currently, there are some diseases of this leaf reported in the field causing yield loss and reducing the economic value. This study aimed to identify the pathogens causing the recent 3 significant diseases of leatherleaf fern, including leaf blight, leaf tip rot, and post-harvest leaf rot, and <em>in vitro</em> analysis of beneficial bacteria, <em>Bacillus velezensis </em>B-27, against the pathogens<em>. </em>The methods used in this study were isolation, pathogenicity test, morphological observation, molecular identification of pathogens, and poisoned food technique of <em>B. velezensis </em>against those pathogens compared to fungicides and bactericides. The results of molecular identification showed that <em>Neopestalotiopsis </em>sp. and <em>Pantoea ananatis </em>caused leaf blight, <em>Fusarium oxysporum</em> f. sp. <em>sesami</em> triggered leaf tip rot, while <em>Calonectria </em>sp. and <em>P. ananatis </em>contributed to post-harvest leaf rot. Based on <em>in vitro</em> analysis, <em>B. velezensis</em> B-27 reduced the growth of the <em>Neopestalotiopsis</em> sp. DM C with the highest inhibition of 95.6%, <em>Neopestalotiopsis </em>sp. DM B with 84.3%, <em>F. oxysporum </em>f. sp. <em>sesami</em> with 61.9%, <em>Calonectria</em> sp. with 93.4%, and inhibited the growth of <em>P. ananatis </em>by producing a clear zone. This research concludes that <em>B. velezensis </em>B-27 has the potential as a biocontrol against pathogens causing significant diseases in leatherleaf ferns due to its ability to inhibit pathogens and its advantage as a beneficial microbe that is environmentally friendly to support sustainable agriculture.

Molecular identification of root-lesion nematodes, Pratylenchus spp. in agricultural crops from Costa Rica

Introduction. The root-lesion nematodes, Pratylenchus spp., have a wide host range and reduce the yield of different crops. Information on the diversity of Pratylenchus species is scarce in Costa Rica. Objective. To identify the Pratylenchus species associated with 12 crops based on the D3 region of the 28S rDNA gene. Materials and methods. During 2013 to 2015, root samples were collected in Alajuela, Cartago, Guanacaste, Heredia, and San José in crops of rice (Oryza sativa), black pepper (Piper nigrum), sugarcane (Saccharum officinarum), aster (Aster sp.), coffee (Coffea arabica), banana (Musa paradisiaca), lily (Lilium sp.), gypsophila (Gypsophila sp.), onion (Allium cepa), potato (Solanum tuberosum), strawberry (Fragaria x ananassa), and leather-leaf fern (Rumohra adiantiformis). The D3 region of the 28S rDNA gene from each population was amplified and sequenced. A GenBank Blast Search was performed for each sequence. The phylogenetic relationships were established by Bayesian Inference. Results. Blast Search indicated the presence of P. pseudocoffeae in aster, P. brachyurus in black pepper, P. crenatus in onion and potato, P. hippeastri and P. gutierrezi in sugarcane and coffee, respectively. Pratylenchus bolivianus in leather-leaf fern and potato, P. penetrans in onion, strawberry, gypsophila, and lily, P. zeae in rice and sugarcane, while P. speijeri in banana. The phylogenetic analysis corroborated the Pratylenchus species identity with exceptions of sequences from 1) banana, grouped to P. coffeae complex group, 2) sugar cane, grouped to P. hippeastri complex group 3) onion and potato were related with P. crenatus, in an independent group, and 4) leather-leaf fern and potato were grouped with P. bolivianus with low resolution. Conclusions. Nine genetic groups of Pratylenchus were found, some of those should be verified with other molecular markers to get a conclusive identification.

First report of Dematophora bunodes causing root rot of taro (Colocasia esculenta ) and leatherleaf fern (Rumohra adiantiformis) in Brazil.

Colocasia esculenta, taro (T), is a major staple food crop in the tropics, including Brazil. Rumohra adiantiformis, leatherhead fern (LF), is broadly cultivated for its ornamental fronds that are used as a component of flower arrangements. Soft root rot of T and LF, and accompanying rapid plant wilt and death, was observed in plantations in Espírito Santo (Brazil), at Venda Nova do Imigrante, in April 2014 (LF) and July 2015 (T). Great losses were observed. Firstly, a few individual scattered plants showed symptoms of disease in the plantations, then aggregates of plants and, after a few seasons, the majority of the plants in the field died before harvest, leading to the abandonment of the activity by farmers. A white mycelial matt was observed on the crown and roots ofying T and LF plants. Infected corms become necrotic and dark brown mycelial strands were observed internally in tissues. Diseased organs were carefully washed and surface sterilized in 10% sodium hypochlorite. Samples of tissue were removed from the boundary of necrotic tissues and placed on potato dextrose-agar (PDA) plates and incubated at 23±2 C in the dark. Homogeneous mycelial colonies were isolated from both T and LF and, upon observation of microscope mounts under an Olympus BX 53 light microscope, pear-shaped hyphal swellings at the septae (Castro et al. 2013) were observed. . A representative isolate from each host was deposited in the local culture collection as COAD 2911 (LF isolate) and COAD 2912 (T isolate). Additionally, DNA was extracted from each culture using the Wizard Genomic DNA Purification Kit (Promega) and the internal transcriptional spacer region was PCR amplified using the primers ITS5 and ITS1 (White et al. 1990). The amplicons were sequenced by MACROGEN (http://www.macrogen.com). Consensus sequences were deposited in GenBank: MW561595 (LF), MW561596 (T). Consensus regions were compared against other sequences available in Genbank. A BLASTn analysis resulted in LF and T sequences respectively 99% (526/531bp) and 98% (412/420 bp) identity with that of Dematophora bunodes (MN984619). Additionally, a phylogenetic analysis of a selected sequence alignment was performed on the CIPRES webportal (Miller et al., 2010) using MrBayes v.3.1.1 (Ronquist & Huelsenbeck, 2003). A phylogenetic tree was generated showing that the placement of LF and T isolates is in D. bunodes (Wittstein et al. 2020). Pathogenicity tests were performed for LF and T isolates against their original hosts. For inoculum, bags of twice-autoclaved parboiled rice were seeded separately with each isolate, which were allowed to colonize the rice for two weeks. Four healthy young LF and T plants were utilized. Two extra healthy plants grown in the same conditions, but not inoculated, served as controls. Thirty g of Dematophora-colonized rice was placed in direct contact with stems or roots of each LF or T plant. Plants were maintained in a dew chamber for 48 h after inoculation and then transferred to a greenhouse bench. All inoculated plants developed wilt and root rot and died after 15-20 days. Controls remained healthy. White mycelial colonies were formed over tissues of diseased LF and T and upon observation under the microscope, typical pear-shaped swellings were observed in slides prepared from newly obtained pure cultures from LF and T. Dematophora bunodes (formerly Rosellinia bunnodes) has a worldwide distribution and is well known as a polyphagous plant pathogen (Farr and Rossman, 2020) but has never been reported as a pathogen either of LF or T before in Brazil and worldwide. Its report on LF and T further expands an already large host-range and resolves the etiology of the disease on LF and T.

PENGARUH TAKARAN MEDIA BALITHI TERHADAP PERTUMBUHAN DAN PRODUKSI DAUN LEATHERLEAF FERN (Rumohra adiantiformis) (G.Forst.) Ching)

Leatherleaf fern ( Rumohra adiantiformis ) could be the cut leaves of ornamental plants as a filler and bouquet. Growing media is one of the important factors to produced growth and yields of leatherleaf. The research aims to study the effects of several dosage Balithi’s media could support to maximizing growth and yields of leatherleaf. The research was conducted at IOCRI (Indonesia Ornamental Crop Research Institute) in June 2014 - December 2015. Experiment used a randomized block design (RBD) two factors with four replications. The size of each plot treatment was 1.2 × 2.1 m. The first factor was the Balithi’s media, namely: 1 dosage Balithi’s media without gliocompos (M1), 1 dosage Balithi’s media with gliocompos (M2), and ½ dosage Balithi’s media with ½ dosage gliocompos (M3). The second factor was the leatherleaf varieties, namely Florida (V1) and Mayfield (V2). The result showed that treatment variety was significantly affected the parameters of crown height, length of strands and number of leaves per plot. The varieties Mayfield growth better than Florida. The Mayfield variety produced 3,961 strands and Florida variety 2,160 strands. M3 was the best media; M3 produced 1,268 leaves, M2 1,082 leaves and M1 1,067 leaves. The best media for growth and yields was M3 (½ dosage Balithi’s media + ½ dosage gliocompos).

Influence of coloured shade nets and seasons on production and quality of cut foliage of leather leaf fern (Rumohra adiantiformis)

Leather leaf fern [Rumohra adiantiformis (G forst) Ching.] was grown under red, green, white and black coloured shade nets permitting light intensities ranging from 240.50 to 370 μ mol m-2 s-1 (75% shade net), for two consecutive years from 2014-16, at ICAR-IIHR, Bengaluru. The influence of coloured nets and the season on cut foliage yield and quality were evaluated. Developmental stages of the fronds under the different coloured nets were also studied. Fronds attained the harvestable maturity stage at 33 days post emergence under red shade net, whereas it took 31.5 days under green shade net. The plants cultivated under red shade net (75% shade) resulted in higher foliage production/plant/ month (6.60) while it was on par with black shade nets in terms of quality of the foliage with respect to length of lamina (24.90 cm) and frond width (17.77 cm). The vase life of the cut foliage grown under red shade net was 47.6 days. Cultivation of leather leaf fern under red shade resulted in maximum cut foliage yield, quality and post harvest life.

Influence of cocopeat based medium and nutrient scheduling on leather leaf fern

Influence of cocopeat based medium and nutrient scheduling on leather leaf fern

Combined Application of Bio-PF and Synthetic Fungicide Suppress Soil Borne Disease Caused by Cylindrocladium sp. in Leather Leaf

An evaluation of formulated Bio-PF with the active ingredient of Pseudomonas fluorescens to reduce synthetic fungicide usage in controlling soil borne disease in leather leaf fern under different shelters was studied. The research was conducted at the experimental field of the Indonesian Ornamental Crops Research Institute (IOCRI) from January to December 2015. Different concentrations of Bio-PF were singly and/nor alternately applied with two different synthetic fungicides were applied on leather leaf plants under UV plastic + 70% black-net and 70% black-net shelters. The results showed that the average disease intensity was higher in 70% black-net shelter. Weekly alternate-application of Bio-PF 5 + Carbendazim & Mancozeb and single Carbendazim & Mancozeb gave lower disease intensity than other treatments with the highest percentage of suppression. These two treatments also improved yield in terms of number and proportion of the preferred grade of harvested leaves. Combined Bio-PF 5 + Carbendazim & Mancozeb gave longer vase life and the application reduced synthetic fungicide usage in controlling the respected disease. In term of synthetic fungicides, Carbendazim & Mancozeb gave more consistent effects on disease suppression, plant growth and foliage production than Asilbensolar & Mancozeb.

DISTRIBUTION AND DEPOSITIONAL HISTORY OF SOME PRE-LAGOONAL HOLOCENE SEDIMENTS IN THE CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIA

An investigation of the pre-lagoonal Holocene sediments from beneath the Ciénaga Grande de Santa Marta (Colombia) was undertaken for the purpose of better understanding the paleogeographical and paleoecological conditions of this region before the formation of the lagoon proper. Core and grab samples were collected from the lagoon for stratigraphic observation and analysis in the laboratory. Beneath the recent lagoonal sediments a deposit of peat with intercalated sand and clay was discovered. Its surface lies at a depth of about 2 m below the hydrographic zero level of the lagoon. Three peat samples, obtained from the upper portion of this deposit, were subjected to micropetrographic and pollen analyses. These analyses revealed that, prior to marine inundation, this region was a coastal marsh-swamp complex similar to the Everglades-mangrove region in southern Florida (U. S. A.). Sample "f" , taken closest to the present sea, represents a red mangrove (Rhizophora mangle) dominated zone, which was relatively exposed to tides and waves, so that the energy was great enough to sweep the sediment surface clean of litter. This implies that the Isla de Salamanca, an almost continuous beach barrier between the present-day lagoon and the Caribbean Sea, must not have been as prominent a barrier as it is today, but that a larger inlet existed near the site of formation of this particular peat sample. The next most inland sample " g" represents a mixed mangrove zone which was somewhat less exposed to current scour and which was presumably situated behind and protected by the former zone. The third sample "h" , taken the furthest inland, represents ponded conditions within a slightly brackish to fresh water marsh dominated by leatherleaf fern (Acrostichum aureum) and sedges. This relatively stable zonation of vegetational environments from marine mangrove in the north to fresh water marshes in the south briefly before the termination of peat formation suggests that the transgression which formed the lagoon was so rapid that marine floral communities had no time to migrate inland and cover more of the submerging swamp surface. This assumption is supported by C14 dates which show that the uppermost peat layers were formed approximately 2 400 years ago in the north and 1 900 years ago in the south, so that the transgression over the swamp should not have taken longer than 500 years. It is recognized, however, that the small number of analyzed samples does not permit far-reaching conclusions. Four different species of molluscs encountered in peat and clay samples from a few locations in the northern and southern Ciénaga are typical brackish water species. This is evidence for the early existence of small low-salinity lagoons and creeks within the marsh-swamp setting. Some additional stratigraphic information was obtained by probing with a steel rod capable of penetrating the recent lagoonal sediments as well as the peat. With reference to the water level a shorter depth down to a "firm substrate" (dense sand or indurated clay) was encountered in the southern part of the lagoon than in the rest of the lagoon. This "substrate high" probably represents a submerged lobe of a former subdelta of the Magdalena River. The common association of peat with layers of sand and clay in this region also points to a nearby source for clastics. In general the discharge of sediments into the swamp was sporadic, with long periods during which the rate of clastic sedimentation was low enough to allow the accumulation of relatively pure peats.

Influence of Substrates and Nutrient levels on Production and Quality of Cut Foliage in Leather Leaf Ferns(Rumohra adiantiformis)

In Leather leaf fern (Rumohra adianti-formis) production, a combination of Cocopeat +Sand+Vermicompost (1: 1: 1 v/v) as substrate and the application of NPK @100: 30: 60 kg/ha/year in six splits at bimonthly intervals (basal dose of full P, 0.1% Arka Microbial Consortium (AMC) as one time application and N and K as splits) resulted in the maximum number of cut foliage/plant, length of lamina, length of stipe, length of frond and width of frond. Chemical analysis of the substrate revealed near neutral pH, optimum levels of organic carbon and avail-able N, high levels of available P, K, Ca, Mg, Fe, Mn, Zn and Cu. The substrate also had higher population of Bacillus sp, Pseudomonas sp and Azotobacter sp as compared to the soil based substrates.

Symptoms of Fern Distortion Syndrome resulting from inoculation with opportunistic endophytic fluorescent Pseudomonas spp.

BackgroundFern Distortion Syndrome (FDS) is a serious disease of Leatherleaf fern (Rumohra adiantiformis). The main symptom of FDS is distortion of fronds, making them unmarketable. Additional symptoms include stunting, irregular sporulation, decreased rhizome diameter, and internal discoloration of rhizomes. We previously reported an association of symptoms with increased endophytic rhizome populations of fluorescent pseudomonads (FPs). The aim of the current study was to determine if FPs from ferns in Costa Rica with typical FDS symptoms would recreate symptoms of FDS.Methodology and FindingsGreenhouse tests were conducted over a 29-month period. Micro-propagated ferns derived from tissue culture were first grown one year to produce rhizomes. Then, using an 8×9 randomized complete block experimental design, 8 replicate rhizomes were inoculated by dipping into 9 different treatments before planting. Treatments included water without bacteria (control), and four different groups of FPs, each at a two concentrations. The four groups of FPs included one group from healthy ferns without symptoms (another control treatment), two groups isolated from inside rhizomes of symptomatic ferns, and one group isolated from inside roots of symptomatic ferns. Symptoms were assessed 12 and 17 months later, and populations of FPs inside newly formed rhizomes were determined after 17 months. Results showed that inoculation with mixtures of FPs from ferns with FDS symptoms, but not from healthy ferns, recreated the primary symptom of frond deformities and also the secondary symptoms of irregular sporulation, decreased rhizome diameter, and internal discoloration of rhizomes.ConclusionsThese results suggest a model of causation of FDS in which symptoms result from latent infections by multiple species of opportunistic endophytic bacteria containing virulence genes that are expressed when populations inside the plant reach a minimum level.

Improved micropropagation protocol for leatherleaf fern (Rumohra adiantiformis) using rhizomes as donor explant

A new micropropagation protocol for leatherleaf fern (Rumohra adiantiformis (G. Forst.) Ching) was successfully established using rhizomes as the donor explant, following appropriate sterilization. Murashige and Skoog (MS) medium containing 0.25mg/l 2,4-dichlorophenoxy acetic acid (2,4-D), 0.2mg/l α-naphthalene acetic acid (NAA), 1.0mg/l 6-benzyl adenine (BA), and 0.5mg/l thidiazuron (TDZ) with 30g/l sucrose (IM-4) was the most appropriate medium for culture initiation. When entire rhizomes harvested from mother stock plants were cultured on a simple paper bridge containing liquid IM-4 medium, culture initiation improved with 3.4 rhizomes regenerated per sub-culture. The average multiplication rate of newly regenerated rhizomes increased to 5.7/rhizome on half-strength MS medium supplemented with 0.05mg/l IAA, 0.25mg/l BA, 0.5mg/l Kin, 1g/l activated charcoal and 20g/l sucrose (MM-5). The level of multiplication peaked in the fifth subculture and retained high quality until the sixth subculture. From the seventh subculture onwards, the quality of regenerated fronds was reduced. The regenerated rhizomes rooted easily on MM-5 and could be acclimatized ex vitro with 97–100% survival.

Increased populations of deleterious fluorescent pseudomonads colonizing rhizomes of leatherleaf fern (Rumohra adiantiformis) and expression of symptoms of fern distortion syndrome after application of Benlate systemic fungicide

The overall objective of the current study was to test two hypotheses: (1) application of the systemic fungicide Benlate to leatherleaf fern results in long-term increases in populations of deleterious fluorescent pseudomonads that endophytically colonize rhizomes; (2) such endophytic colonization, resulting from Benlate treatment, is associated with damage to leatherleaf fern and development of symptoms of fern distortion syndrome (FDS). Mean populations of fluorescent pseudomonads and total aerobic bacteria in the rhizosphere were significantly increased 3 months after the application of Benlate 50 WP and Benlate 50 DF as foliar sprays and drenches, compared to populations in the non-treated control. In another test, at 5 months after treatment, endophytic populations of fluorescent pseudomonads inside rhizomes of plants treated with Benlate 50 WP and Benlate 50 DF (both from DuPont) were significantly higher than populations in rhizomes of plants treated with three different generic sources of Benlate 50 WP, the active ingredient benomyl, and MBC. In the same test, treatments with the two DuPont sources of Benlate, but not the generic sources, benomyl, or MBC resulted in reduced overall growth of plants, including reductions weight of fronds, roots and rhizomes and caliper of rhizomes. Three long-term experiments examined the effect of Benlate 50 WP and Benlate 50 DF on populations of fluorescent pseudomonads and development of distortions of frond growth and other symptoms associated with FDS. In two tests at 24 months after application, treatment with both formulations of Benlate increased endophytic populations of fluorescent pseudomonads inside rhizomes, compared to controls, in both experiments, and endophytic populations inside petioles of fronds arising from rhizomes were significantly greater with both Benlate treatments in one test where this parameter was measured. Also at 24 months after application, the Benlate treatments were associated with significant increases in severity of FDS, using a previously reported rating scale and by measuring several other parameters associated with FDS. In the third long-term test, the first crop of fronds was cut 24 months after treatment. Four weeks later, the numbers of actively growing rhizomes (that had produced new fronds) were significantly reduced on Benlate-treated plants, compared to the controls. At 6 months after cutting (30 months after Benlate treatments), weights of fronds were lower on Benlate-treated plants than on controls. Characterization of fluorescent pseudomonads isolated from inside rhizomes and petioles at 24 months after treatment revealed that applications of Benlate resulted in a marked increase in pectinolytic activity. DNA sequencing of 150 strains of fluorescent pseudomonads from inside rhizomes and 60 from inside petioles at 24 months after application of Benlate indicated low matches to type strains in the ribosomal data base. Phylogenetic characterization of the strains indicated the existence of 10 clusters. Pronounced shifts in frequency of strains in the various clusters were noted with Benlate treatment: over 70% of strains from rhizomes of Benlate-treated plants belonged to cluster E3, compared to only 2% of the strains from control rhizomes, and 98% of the control strains belonged to clusters C, D2, F, and G, while none of the strains from petioles or rhizomes of Benlate-treated plants belonged to these four clusters. In summary, treatment of leatherleaf fern with Benlate 50 WP and Benlate 50 DF from DuPont led to a progression of long-term deleterious effects on leatherleaf fern that were associated with increased populations of fluorescent pseudomonads that were functionally and phylogenetically different from pseudomonads from control plants.

DIAGNOSIS DAN PENGENDALIAN PENYAKIT ANTRAKNOSA PADA PAKIS DENGAN FUNGISIDA

Leatherleaf fern is an important export commodity of floriculture. One of the most destructive disease on leatherleaf fern is anthracnose. The aim of this study was to identify the causal agent of antracnose-like disease on leatherleaf fern, to detect the pathogen in soil, and to control the disease with fungicides. Diagnosis was done with modified Koch Postulate. Identification of the pathogen was done by direct observation from the symptom under microscope. Isolation of the pathogen from die back leaves and soil was done on PDA. Inoculation was done on apple fruit indicator. The tested fungicides were difeconazole, benomyl, mancozeb+cymoxanil 8/64, tebuconazole, acebenzolar e-methyl+mancozeb 1/48, mancozeb, and 73.8% mancozeb + 6.2% carbendazim. In vitro test was done by poisoned food technique at 0% (checked), 0.025%, 0.05%, 0.1%, 0.2% and 0.4% concentration, while field test was done at 0.4% level concentration. Field application of pesticides was conducted by spraying twice a week for eight weeks. The result showed that the anthracnose-like disease of leatherleaf fern was anthracnose caused by Colletotrichum sp. The pathogen was found and survived in soil. In vitro test showed that 0.4% was the best concentration to inhibit mycelium growth. Based on this result, field experiment was done on 0.4% concentration of fungicides. The mixture of 73.8% mancozeb and 6.2% carbendazim was the most effective fungicide to inhibit Colletotrichum sp. in vitro. Spraying with 0.4% concentration eight times significantly reduced disease intensity in the field.

A Strain of Japanese holly fern mottle virus Infecting Leatherleaf Fern in the United States

Leatherleaf fern, a popular cut foliage plant for use in flower arrangements, was found showing virus-like symptoms at a local nursery in Baton Rouge, LA. The causal agent of the disease was determined to be a strain of Japanese holly fern mottle virus. The virus was identified by dsRNA, RT-PCR, and sequence analyses. The potential negative impact of this pathogen on leatherleaf fern production and its spread within the crop should be a concern for leatherleaf fern growers. Accepted for publication 17 December 2010. Published 28 January 2011.

In Vitro Regeneration of Leatherleaf Fern (Rumohra adiantiformis (G.Forst.) Ching)

Abstract Rumohra adiantiformis, also known as “leatherleaf fern”, is an ornamental species that, because of its long display life, is widely used in floral arrangements. In this study, a new protocol for in vitro regeneration of the leatherleaf fern was established. For spore germination, two culture media (MS and Knop) were assessed with presence or absence of 1g L−1 activated charcoal (AC) under different light and dark conditions. Frond, frond microcuttings, and prothallus explants were evaluated on Knop regeneration medium supplemented with 1g L−1 AC, 0.5% agar, pH 5.0 in combination with 2,4 dichlorophenoxyacetic acid (2,4-D: 0.0, 0.1, 0.5 and 1.0 mg L−1) and 6-benzylamino purine (BA: 0.0, 0.1, 0.5 and 1.0 mg L−1). For rooting, four levels of α-naphthaleneacetic acid (NAA: 0.0, 0.01, 0.1 and 0.2 mg L−1) were tested. After 18 days of culture, spore germination rate was 100% on Knop medium with AC and 8 h light/16 h dark. After 120 days of culture, sporophytes 1.7 ± 0.4 cm in length developed on Knop m...

First Report of Anthracnose of Swiss Cheese Plant and Phoma Rot of Leather Leaf Fern in Japan

First Report of Anthracnose of Swiss Cheese Plant and Phoma Rot of Leather Leaf Fern in Japan

Colonization of citrus leaves and secondary conidiation response to citrus flower extracts by non-postbloom fruit drop strains of Colletotrichum acutatum

Postbloom fruit drop (PFD) is caused by a unique strain of Colletotrichum acutatum that infects citrus flowers, producing necrotic lesions on petals and the abscission of fruitlets. This strain survives on vegetative tissues during non-flowering periods, and conidial production on colonized tissue is stimulated by flower extracts. Genetically distinct strains from other hosts can cause PFD symptoms, but their survival on vegetative tissues and ability to sporulate in response to flower extracts is unknown. Isolates from anthracnose-affected blueberry, leatherleaf fern, strawberry, Key lime and PFD-affected sweet orange were evaluated for their ability to survive on leaves after inoculation and to produce conidia in response to flower extracts. Viable propagules were recovered from leaves inoculated with all non-PFD isolates and recovery of some was equal to or greater than that of the PFD isolate. The number of propagules recovered increased for all isolates after treatment with flower extracts and was comparable across isolates. Application of sucrose to leaves inoculated with the PFD isolate increased the number of propagules recovered from leaves, suggesting that the response to flower extracts was nutritional. Non-PFD isolates of C. acutatum can colonize and reproduce on leaves, and their inability to cause epidemics is probably due to their reduced pathogenicity to flowers.

Fern Distortion Syndrome of Leatherleaf Fern in Costa Rica: Symptoms, Incidence, and Severity.

A syndrome has been recognized on leatherleaf fern (Rumohra adiantiformis) in Costa Rica for many years that causes widespread damage but has not been described in the literature. A full description of the syndrome, termed fern distortion syndrome (FDS), is reported here, along with evidence that FDS is a new disease and that it is associated with endophytic fluorescent pseudomonads but not with any other major groups of pathogens or pests. The main aboveground symptoms of FDS are twisting and distortions of fronds, which make the fronds unmarketable. In advanced cases of FDS, fronds are often thickened, new frond growth ceases or slows dramatically, and uneven sporulation is apparent on the underside of fronds. Symptoms of FDS belowground are reduced diameter of rhizomes and reduced overall root mass. The incidence of FDS in Costa Rica was typically over 80%, and severity typically ranged from 1.26 to 2.48 using a 0 to 3 rating scale in fields propagated vegetatively with rhizomes from fields with FDS. In contrast, in three fields planted 1.5 to 4 years previously with rhizomes derived from tissue culture, incidence and severity were markedly lower: 23 to 34% and 0.24 to 0.36, respectively. Paired sampling of symptomatic and asymptomatic plants revealed significantly greater populations of fluorescent pseudomonads inside rhizomes of symptomatic plants.

Effects of Harvesting on Population Structure of Leatherleaf Fern (Rumohra adiantiformis (G. Forst.) Ching) in Brazilian Atlantic Rainforest

Among ferns, the leatherleaf fern (Rumohra adiantiformis) is of particular economic importance. The fronds are sold around the world for flower arrangements. In Brazil, these fern fronds represent an income source for numerous households, working with a traditional management system with a maximum of three annual collections in the same area. The purpose of this study was to evaluate the demographic structure of managed R. adiantiformis populations in the south of Brazil and verify the sustainability of the harvesting activity in this region. The study was conducted in an area of Atlantic Rainforest in the State of Rio Grande do Sul. The demographic structure of the managed populations was evaluated in permanent plots, where fronds in the different development phases were counted quarterly for one year. Rainfall was identified as the main factor influencing bud emergence and development. A reduction in R. adiantiformis populations related to forest regeneration was also observed. Fast frond regeneration and the absence of differences between managed and non-managed populations concerning the proportions of buds and young fronds corroborate the ecological sustainability of the management system used by the local harvesters. The results obtained differ largely from those of populations studied in South Africa, where R. adiantiformis plants seem unable to maintain frond density and size when harvested. These contrasting results are probably related to climatic differences between these areas, especially annual rainfall, which is higher in Brazil allowing for the rapid regeneration and sustainable management of this resource in the Brazilian Atlantic Rainforest.

Host Range and Genetic Relatedness of Colletotrichum acutatum Isolates from Fruit Crops and Leatherleaf Fern in Florida

Isolates of Colletotrichum acutatum were collected from anthracnose-affected strawberry, leatherleaf fern, and Key lime; ripe-rot-affected blueberry; and postbloom fruit drop (PFD)-affected sweet orange in Florida. Additional isolates from ripe-rot-affected blueberry were collected from Georgia and North Carolina and from anthracnose-affected leatherleaf fern in Costa Rica. Pathogenicity tests on blueberry and strawberry fruit; foliage of Key lime, leatherleaf fern, and strawberry; and citrus flowers showed that isolates were highly pathogenic to their host of origin. Isolates were not pathogenic on foliage of heterologous hosts; however, several nonhomologous isolates were mildly or moderately pathogenic to citrus flowers and blueberry isolates were pathogenic to strawberry fruit. Based on sequence data from the internal transcribed spacer (ITS)1-5.8S rRNA-ITS2 region of the rDNA repeat, the glutaraldehyde-3-phosphate dehydrogenase intron 2 (G3PD), and the glutamine synthase intron 2 (GS), isolates from the same host were identical or very similar to each other and distinct from those isolated from other hosts. Isolates from leatherleaf fern in Florida were the only exception. Among these isolates, there were two distinct G3PD and GS sequences that occurred in three of four possible combinations. Only one of these combinations occurred in Costa Rica. Although maximum parsimony trees constructed from genomic regions individually displayed little or no homoplasy, there was a lack of concordance among genealogies that was consistent with a history of recombination. This lack of concordance was particularly evident within a clade containing PFD, Key lime, and leatherleaf fern isolates. Overall, the data indicated that it is unlikely that a pathogenic strain from one of the hosts examined would move to another of these hosts and produce an epidemic.