Fungus Corynespora Cassiicola Research Articles

Assessing Soybean Cultivar Resistance to Target Spot Using a Detached Leaf Assay

Target spot (TS), caused by the fungus Corynespora cassiicola, is a foliar disease of increasing importance to soybean in the United States. Identifying cultivar resistance to TS is challenging. The objective of this research was to determine the reactions of a diverse collection of soybean genotypes to TS using a detached leaf inoculation method. A detached unifoliate leaf of each soybean genotype was placed in a Petri dish on moist filter paper, wounded at three locations, inoculated with 10 μl of a 105-conidial suspension of C. cassiicola, and incubated at room temperature (23°C). The percent leaf area with TS symptoms (TSS) was measured digitally at 7, 10, 14, and 17 days after inoculation (DAI), and the area under the disease progress curve (AUDPC) was calculated. Thirty-seven soybean genotypes and three soybean cultivars were evaluated in three replicated trials. At 17 DAI, TSS ranged from 2 to 84%. Significant differences occurred between soybean genotypes at each rating time in each trial. Across the three trials, the reaction of most soybean genotypes ranged from resistant to susceptible. These soybean genotypes were evaluated in the field with natural inoculum at two locations in 2022. TS developed late but differed significantly between genotypes, averaging from 0.35 to 3.35% TSS. Field results were not significantly correlated to the detached leaf results. The detached leaf assay is another tool for screening soybean genotypes for resistance to TS but needs field validation. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Sensitivity of Hevea brasiliensis clones to isolates representing distinct races of the Corynespora cassiicola pathogen

AbstractCorynespora leaf fall disease caused by the fungus Corynespora cassiicola is a major leaf disease of Hevea brasiliensis, the commercial source of natural rubber. Different clones of H. brasiliensis show varying levels of sensitivity towards different strains of C. cassiicola. The genetic mechanism behind the differential sensitivity of H. brasiliensis clones has to be identified in order to develop clones resistant to wider range of C. cassiicola strains. The available information on the sensitivity of H. brasiliensis clones is based on the observation of natural infection or infection of detached leaves. In the present study, the sensitivity of seven H. brasiliensis clones towards two strains of C. cassiicola belonging to two different races was determined using a more precise method by artificial infection of the plants under controlled conditions. Strain CLN 16 was found to be more virulent compared with CSB 16, as it induced more severe symptoms in a shorter period. Among the four different stages of leaves, Stage II leaves with copper brown to apple green colour showed higher sensitivity to both strains followed by Stage III leaves with apple green appearance. Among the clones, RRIM 600 had a higher susceptibility towards CSB 16; however, it was the most resistant clone towards CLN 16. Clone PB 350 showed the highest susceptibility towards CLN 16 whereas RRIM 928 showed the highest resistance towards CSB 16. The present study provides a platform for further studies leading to the development of H. brasiliensis clones with resistance towards wider range of C. cassiicola strains.

Isolation and Identification of Secondary Metabolites Produced by Phytopathogenic Fungus Corynespora cassiicola from Hevea brasiliensis

The secondary metabolites of the phytopathogenic fungus Corynespora cassiicola CC01 from Hevea brasiliensis were investigated. As a result, two new compounds, 5-acetyl-7-hydroxy-6- methoxybenzofuran-2(3H)-one (1) and (S)-2-(2,3-dihydrofuro [3,2-c]pyridin-2-yl)propan-2-ol (2), together with seven known compounds, 4,6,8-trihydroxy-3,4-dihydronaphthalen-1(2H)-one (3), 3,6,8-trihydroxy-3,4-dihydronaphthalen-1(2H)-one (4), curvulin acid (5), 2-methyl-5-carboxymethyl- 7-hydroxychromone (6), tyrosol (7), p-hydroxybenzoic acid (8) and cerevisterol (9), were isolated from the fermentation extract by comprehensive silica gel, reverse phase silica gel, Sephadex-LH20 column chromatography and high-performance liquid chromatography (HPLC). The structures of these compounds were identified by using high-resolution electrospray mass spectrometry (HRESIMS), nuclear magnetic resonance spectroscopy (NMR), optical rotation, ultraviolet and infrared spectroscopy techniques and a comparison of NMR data with those reported in the literature. Compounds 1 and 2 were new compounds, and compounds 3-9 were discovered from this phytopathogenic fungus for the first time. Compounds 1-9 were tested for phytotoxicity against the fresh tender leaf of Hevea brasiliensis, and the results show that none of them were phytotoxic. Additionally, these compounds were subjected to an antimicrobial assay against three bacteria (E. coli, methicillin-resistant Staphylococcus aureus and Micrococcus luteus), but they showed no activity.

Evaluating target spot (Corynespora cassiicola) resistance in soybean (Glycine max (L.) Merrill) in a controlled environment

Target spot, caused by the fungus Corynespora cassiicola, has been an increasing problem for soybean growers in the Mid-south and southeastern United States. With favorable environmental conditions, the disease causes premature defoliation and substantial yield losses; therefore, identifying resistant germplasm is critical. Herein, a rapid screening technique for target spot resistance was used to evaluate varieties for possible use in a breeding program. Fifteen soybean varieties, along with a known susceptible variety, were evaluated against isolate C. cassiicola LIM01. Two of the sixteen varieties were identified as resistant and nine were moderately susceptible. A subset of these was evaluated with three additional C. cassiicola isolates; these isolates differed in combinations of cassiicolin-encoding genes. The soybean varieties Bedford and Council were observed to be resistant to each of the C. cassiicola isolates tested in this study but need to be further validated in a field environment. Plant populations developed using these parent varieties could provide a foundation for QTL mapping of regions conferring resistance to target spot and identifying disease resistance mechanisms that can be transferred into elite soybean varieties through marker-assisted breeding.

Complete genome sequence of a novel fusarivirus from the phytopathogenic fungus Corynespora cassiicola

Corynespora cassiicola is an important phytopathogenic fungus that severely impairs crop production. Here, we report the molecular characterization of a novel positive-sense single-stranded RNA (+ssRNA) mycovirus, Corynespora cassiicola fusarivirus 1 (CcFV1), isolated from C. cassiicola strain 20200826-3-1. Excluding the poly(A) tail, the genome of the virus is 6491 nt in length and contains three putative open reading frames (ORFs). The large ORF1 encodes a polypeptide of 1524 aa with a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase (Hel) domain. BLASTp analysis showed that CcFV1 ORF1 has the highest similarity to Setosphaeria turcica fusarivirus 1 (StFV1, 50.45% identity, E-value 0.0). ORF2 encodes a polypeptide with a conserved chromosome segregation ATPase (Smc) domain. The smaller ORF3 encodes a polypeptide with an unknown function. Phylogenetic analysis based on the ORF1- encoded polypeptide showed that CcFV1 is phylogenetically related to members of the newly proposed family "Fusariviridae". Thus, we suggest that CcFV1 might be a novel member of the family "Fusariviridae", and is the first to be discovered in C. cassiicola.

Morphological and pathogenic characterization of Corynespora cassiicola isolates reveals specific genotypic interactions in soybean

AbstractSoybean target spot, caused by the fungus Corynespora cassiicola, is an important disease in northwestern Argentina (NWA). A cultural, morphological, and virulence characterization of 24 C. cassiicola isolates from different geographic localities in NWA was performed. The isolates were classified into five different cultural phenotypes, one of which has not been previously described. The ribosomal DNA internal transcribed spacer region sequence from five representative isolates (587 bp) exhibited 100% identity with C. cassiicola. A high variability of conidial morphology was observed among isolates, but no correlation with cultural phenotype was observed. When the soybean cultivar A 8000 RG was challenged with the 24 isolates, different degrees of virulence were observed, ranging from highly virulent to nonvirulent. No association of virulence with cultural or morphological characters was observed, but a relationship with geographical origin was demonstrated. Histopathological studies were performed on a nonvirulent and a highly virulent isolate. Microscopic observations of infected tissues of the former showed low mycelium development restricted to the upper epidermis, a thickening of the cuticle and primary wall of subepidermal cells, and accumulation of callose in phloematic vessels. In tissue infected with the latter, there was abundant mycelium development accompanied by cellular disorganization in mesophyll cells. Pathological challenges of isolates on nine different cultivars indicated that the degree of virulence of isolates depends on the plant genotype, demonstrating that the C. cassiicola–soybean interaction is highly specific. Understanding the genetic basis of this interaction will provide new information for better disease management and breeding strategies.

High dilution of Belladonna affect the mycelial growth of Corynespora cassiicola in vitro

Introduction: The target spot is a disease caused by fungus Corynespora cassiicola (Berk. & Curt.) Wei. This disease has occurred in several states of Brazil. It is a late season disease and causes economic losses in various crops such as soybeans [1]. Currently there is no adequate treatment for the control of C. cassiicola in organic cultivation of soybeans, since the application of fungicides for the control and management of diseases is not allowed by Brazilian legislation [2]. Thus, the purpose of this experiment was to test the effectiveness of high dilutions of Belladonna in vitro on mycelial growth of Corynespora cassiicola.
 
 Materials and Methods: The preliminary tests were conducted at the Laboratory of Plant Pathology, State University of Maringá (UEM). The fungal isolate of C. cassicola was obtained from Embrapa Soja. The fungus was peaked and grown on PDA (potato dextrose agar) maintained at 25°C ± 2 and 12h photoperiod. Belladonna dilutions (6, 12, 18, 24 and 30dH) were obtained according to the Brazilian Homeopathic Pharmacopoeia [3]. PDA culture medium plus Belladonna dilutions (6, 12, 24 and 30dH) beyond the control containing distilled water were placed in petri dishes after filtration through a Millipore membrane (pore diameter of 0.45µm ). After medium solidification, a disc of mycelium (4 mm diameter) of C. cassiicola was peaked towards the center of each plate and sealed with plastic wrap and then incubated at 25°C with 12h photoperiod. The mycelial growth was measured daily for 8 days. The control consisted of distilled water. The data were analyzed by ANOVA and means were compared by Scott-Knott test (P ≤ 0.05).
 
 Results and Discussion: All dilutions of Belladonna (6, 12, 24, 30dH) were effective (p

Genomic Characteristics and Comparative Genomics Analysis of Two Chinese Corynespora cassiicola Strains Causing Corynespora Leaf Fall (CLF) Disease.

Rubber tree Corynespora leaf fall (CLF) disease, caused by the fungus Corynespora cassiicola, is one of the most damaging diseases in rubber tree plantations in Asia and Africa, and this disease also threatens rubber nurseries and young rubber plantations in China. C. cassiicola isolates display high genetic diversity, and virulence profiles vary significantly depending on cultivar. Although one phytotoxin (cassicolin) has been identified, it cannot fully explain the diversity in pathogenicity between C. cassiicola species, and some virulent C. cassiicola strains do not contain the cassiicolin gene. In the present study, we report high-quality gapless genome sequences, obtained using short-read sequencing and single-molecule long-read sequencing, of two Chinese C. cassiicola virulent strains. Comparative genomics of gene families in these two stains and a virulent CPP strain from the Philippines showed that all three strains experienced different selective pressures, and metabolism-related gene families vary between the strains. Secreted protein analysis indicated that the quantities of secreted cell wall-degrading enzymes were correlated with pathogenesis, and the most aggressive CCP strain (cassiicolin toxin type 1) encoded 27.34% and 39.74% more secreted carbohydrate-active enzymes (CAZymes) than Chinese strains YN49 and CC01, respectively, both of which can only infect rubber tree saplings. The results of antiSMASH analysis showed that all three strains encode ~60 secondary metabolite biosynthesis gene clusters (SM BGCs). Phylogenomic and domain structure analyses of core synthesis genes, together with synteny analysis of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) gene clusters, revealed diversity in the distribution of SM BGCs between strains, as well as SM polymorphisms, which may play an important role in pathogenic progress. The results expand our understanding of the C. cassiicola genome. Further comparative genomic analysis indicates that secreted CAZymes and SMs may influence pathogenicity in rubber tree plantations. The findings facilitate future exploration of the molecular pathogenic mechanism of C. cassiicola.

Microtiter method to monitor Corynespora cassiicola and sensitivity of the pathogen to carbendazim, prothioconazole and pyraclostrobin

The fungus Corynespora cassiicola causes target spot on soybeans in Brazil and one of the recommended controls for this disease involves the use of fungicides. Here, we evaluated the sensitivity of C. cassiicola isolates to fungicides, comparing the effective concentrations required to inhibit 50% of fungal growth (EC50) using a colorimetric microtiter method, with the EC50 determined by mycelial growth inhibition in a fungicide-amended medium obtained by Xavier et al. (2013), for 16 isolates for carbendazim and prothioconazole. The correlation between EC50 values for both methods were 0.90 and 0.88 for carbendazim and prothioconazole, respectively. After this, the sensitivities of 134 C. cassiicola isolates collected in soybean fields in Paraná (PR) and Mato Grosso (MT) in the 2012/13 and 2013/14 crop seasons to carbendazim, prothioconazole, and pyraclostrobin fungicides were evaluated using microtiter method. The spores of the isolates were diluted in Yeast Bacto Acetate culture medium and added to fungicide solutions at concentrations of zero; 0.0032; 0.016; 0.08; 0.4; 2; 10; and 50 μg mL−1. A microplate reader with a 540 nm wavelength was used to estimate the EC50 values. Isolates showed growth inhibition at concentrations higher than 50 μg mL−1, showing a high frequency of resistant isolates, in total, 67% of the isolates from PR and 88% from MT (carbendazim); 99% from PR and 82% from MT (pyraclostrobin); and 11% from PR and 9% from MT (prothioconazole). The results showed that the lower control efficiency for target spot in soybeans in PR and MT to MBC and QoI fungicides could be associated with the presence of resistant isolates.

Corynespora cassiicola in soybean seeds – incidence and transmission

The fungus Corynespora cassiicola, causal agent of target spot in soybeans, has been considered, from the seed pathology point of view, a seed-borne pathogen of limited importance. Therefore, little importance has been given to the role of the seeds in the transmission of this pathogen. The objectives of this study were to determine the incidence of C. cassiicola in soybean seeds and evaluate the effects of this seed-borne pathogen, inoculated in the seeds, in relation to physiological and epidemiological parameters. The experiments were carried out at TAGRO and Embrapa Western Agriculture under lab (blotter test and seed germination test) and greenhouse conditions (growing on test). The fungus C. cassiicola was detected in 11.3% of the 639 seed samples analyzed, with an average incidence of 0.91% and maximum of 8.5%. The transmission of C. cassiicola from the seeds to above-ground parts of soybean seedlings was demonstrated, by pathogen establishment on the cotyledon, showing circular lesions with concentric rings, reddish-brown in the center and surrounded by a yellowish green halo, as a typical symptoms of target spot. Reddish-brown lesions on the roots and stem of the seedlings were also observed. Considering a sample seed with 66.0% of C. cassiicola incidence, the symptomatic transmission based on cotyledon symptoms was 42.2%, corresponding to a transmission rate of 2.4:1. This is the first report, in a quantified way, about the transmission of C. cassiicola from the seeds to above-ground parts of soybean seedlings. When compared to non-inoculated seeds, seed germination, seedling emergence and seedling initial development were influenced by the presence of the pathogen in the seeds, with the lowest values being observed when the seeds were inoculated.

Complete genome sequence of a novel mycovirus isolated from the phytopathogenic fungus Corynespora cassiicola in China.

A novel mycovirus, named "Corynespora cassiicola bipartite mycovirus 1" (CcBV1), was isolated from a phytopathogenic fungus, Corynespora cassiicola, the causal agent of rubber leaf fall disease. The nucleotide sequence of the complete genome of CcBV1, which consists of two double-stranded RNA (dsRNA) segments, was determined. The first dsRNA is 2,002bp in length and contains a single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) (69kDa), while the second is 1,738bp in length and contains a single ORF encoding a hypothetical protein of unknown function, with an approximately molecular weight of 36kDa. The amino acid sequences of the both deduced proteins are most similar (58.9% and 45.1% identity, respectively) to those of Cryphonectria parasitica bipartite mycovirus 1 (CpBV1). Phylogenetic analysis indicated that CcBV1 clusters together with CpBV1 and other unassigned dsRNA mycoviruses. To the best of our knowledge, this represents the first report of a mycovirus infecting C. cassiicola.

Whole-genome analysis of bacillus velezensis ZF2, a biocontrol agent that protects cucumis sativus against corynespora leaf spot diseases.

Bacillus spp. have been widely described for their potentials to protect plants against pathogens. Here, we reported the whole genome sequence of Bacillus velezensis ZF2, which was isolated from the stem of a healthy cucumber plant. Strain ZF2 showed a broad spectrum of antagonistic activities against many plant bacterial and fungal pathogens, including the cucumber leaf spot fungus Corynespora cassiicola. The complete genome of B. velezensis ZF2 contained a 3,931,418-bp circular chromosome, with an average G + C content of 46.50%. Genome comparison revealed closest similarity between ZF2 and other B. velezensis strains. Genes homologous to 14 gene clusters for biosynthesis of secondary metabolites were identified in the ZF2 genome. Also identified were a number of genes involved in bacterial colonization, including the genes for motility, biofilm formation, flagella biosynthesis, and capsular biosynthesis. Numerous genes associated with plant-bacteria interactions, including cellulase or protease biosynthesis, and plant growth promotion were also identified in the ZF2 genome. Overall, our data will aid future studies of the biocontrol mechanisms of B. velezensis ZF2 and promote its application in vegetable disease control.

Field efficacy of chemical fungicides on rubber leaf fall disease (Corynespora cassiicola) in Central Vietnam

Corynespora leaf fall disease (CLF), caused by the fungus Corynespora cassiicola (Berk. & Curt.) Wei, has occurred and become a serious disease on rubber (Hevea brasiliensis) in Asian countries, including Vietnam. Field experiments were conducted in order to evaluate the efficacy of four chemical fungicides difenoconazole, difenoconazole+propiconazole, epoxiconazole and tebuconazole for controlling CLF in Thua Thien Hue province, Central Vietnam. These insecticides were applied at recommended field rates. The results showed that all the four tested fungicides were moderate or high efficacy against CLF. The efficacy was highest with difenoconazole (64.4–71.5%) on rubber planted at both the two different ecological zones. These results suggest that difenoconazole application provides one potential component of an effective CLF control strategy for rubber farmers.

Endophytes from Wild Rubber Trees as Antagonists of the Pathogen Corynespora cassiicola.

The Corynespora leaf fall disease of rubber trees, caused by the necrotrophic fungus Corynespora cassiicola, is responsible for important yield losses in Asian and African plantations, whereas its impact is negligible in South America. The objective of this study was to identify potential antagonists of C. cassiicola among fungal endophytes (i.e., Pestalotiopsis, Colletotrichum, and Trichoderma spp.) isolated from wild and cultivated rubber trees distributed in the Peruvian Amazon. We first tested the endophytes in dual in vitro confrontation assays against a virulent C. cassiicola isolate (CCP) obtained from diseased rubber trees in the Philippines. All Trichoderma isolates overran the CCP colony, suggesting some antagonistic mechanism, while species from the other genera behaved as mutual antagonists. Trichoderma isolates were then tested through antibiosis assays for their capacity to produce growth-inhibiting molecules. One isolate (LA279), recovered as an endophyte from a wild Hevea guianensis specimen and identified as Trichoderma koningiopsis, showed significant antibiosis capacity. We demonstrated that LA279 was also able to endophytically colonize the cultivated rubber tree species (H. brasiliensis). Under controlled laboratory conditions, rubber plants were inoculated with three Trichoderma strains, including LA279, in combination with the pathogenic CCP. Results showed that 1 week preinoculation with the endophytes differentially reduced CCP mycelial development and symptoms. In conclusion, this study suggests that T. koningiopsis isolate LA279-and derivate compounds-could be a promising candidate for the biological control of the important rubber tree pathogen C. cassiicola.

Characterization and control of the causal agent of leaf spot in strawberry (Fragaria ananassa) under greenhouse conditions

Strawberry (Fragaria ananassa) plants showing symptoms of leaf spot were found in the producing areas of Manchay Bajo, Pachacamac District, Lima, Peru. The responsible pathogen was isolated and observed under a microscope to examine its morphological characteristics and the size of its structures, resulting in its identification as the fungus Corynespora cassiicola. Healthy strawberry plants that had been inoculated with C. cassiicola in a greenhouse developed lesions after 3 days and exhibited symptoms consisting of dark brown spots that had light brown centers and were surrounded by yellow halos, which coalesced and subsequently caused necrosis of the whole leaf. In vitro tests demonstrated that the fungus Trichoderma harzianum strain T-22 showed antagonistic activity against C. cassiicola, causing 41.8% mycelial growth inhibition, and the fungicides fosetyl-aluminum (Aliette®) and thiabendazole (Mertect®a) inhibited mycelial growth by 100.00% and 96.32%, respectively. However, in vivo, 0.75 g/L of the fungicide azoxystrobim (Stronsil®) gave the best control of C. cassiicola and the lowest area under the disease progress curve (AUDPC), followed by 1.5 mL/L of thiabendazole (Mertect) under greenhouse conditions. The isolate was found to be pathogenic, and its morphological identification was confirmed.

Corynespora cassiicola causing leaf spots on Boehmeria nivea (rami) in Brazil

A new leaf spot disease caused by necrotrophic fungus Corynespora cassiicola is reported on Boehmeria nivea for the first time in Brazil. Identity was clarified based on morphological and molecular evidence and pathogenicity to ramie was demonstrated.

Development and validation of diagrammatic scale to assess target spot severity in cotton

Due to the emergence of target spot disease on cotton, caused by the fungus Corynespora cassiicola, the aim of this study was the development and validation of a diagrammatic scale to assess the severity of target spot on cotton leaves using Lin’s statistic and linear regression models. For the design of the scale, 200 cotton leaves were collected from naturally infected plants. Severity was measured by APS assess image analysis software. The diagrammatic scale was developed with seven levels of severity: 1%, 2%, 5%, 9%, 19%, 37 and 53%. Validation was determined by severity estimates of 50 leaves by five experienced and five inexperienced evaluators. The first assessment was performance without a scale and the second with a scale aid. The data were analyzed by two methods: Lin’s statistics and linear regression. The diagrammatic scale aid reduced the absolute and relative error and improved precision (R2 = 0.79 and 0.91 without and with the scale, respectively). Evaluators overestimated the severity without the scale. Agreement (Lin’s concordance correlation coefficient, pc = 0.83 and 0.94, without and with the scale, respectively) and accuracy (Bias correction factor, Cb = 0.93 and 0.98, without and with the scale, respectively) were improved with the scale. The agreement between experience evaluators was higher with the scale. The use of the proposed diagrammatic scale contributed to assessment of target spot in cotton leaves by improving inter- and intra-rater reliability and accuracy of experienced and inexperienced evaluators.

Transcriptome and miRNA analyses of the response to Corynespora cassiicola in cucumber

Cucumber (Cucumis sativus L.) target leaf spot (TLS), which is caused by the fungus Corynespora cassiicola (C. cassiicola), seriously endangers the production of cucumber. In this assay, we performed comprehensive sequencing of the transcriptome and microRNAs (miRNAs) of a resistant cucumber (Jinyou 38) during C. cassiicola inoculation using the Illumina NextSeq 500 platform. The possible genes related to the response to C. cassiicola were associated with plant hormones, transcription factors, primary metabolism, Ca2+ signaling pathways, secondary metabolism and defense genes. In total, 150 target genes of these differentially expressed miRNAs were predicted by the bioinformatic analysis. By analyzing the function of the target genes, several candidate miRNAs that may be related to the response to C. cassiicola stress were selected. We also predicted 7 novel miRNAs and predicted their target genes. Moreover, the expression patterns of the candidate genes and miRNAs were tested by quantitative real-time RT-PCR. According to the analysis, genes and miRNAs associated with secondary metabolism, particularly the phenylpropanoid biosynthesis pathway, may play a major role in the resistance to C. cassiicola stress in cucumber. These results offer a foundation for future studies exploring the mechanism and key genes of resistance to cucumber TLS.

Corynespora cassiicola causes leaf spots on the ornamental plant Allamanda cathartica in Brazil

The necrotrophic leaf spot fungus Corynespora cassiicola is recorded for the first time attacking Allamanda cathartica in the host’s center of origin in Brazil. The pathogen was identified using morphological features as well as molecular analysis and its pathogenicity was confirmed by fulfilling Koch’s postulates.

REACTION OF PAPAYA GENOTYPES TO TARGET SPOT AND ACTIVITY OF PLANT EXTRACTS AND Bacillus spp. ON Corynespora cassiicola

ABSTRACT Papaya target-spot, caused by fungus Corynespora cassiicola presents a wide geographic distribution, causing leaf spots in several hosts. The aim of this research was to evaluate the behavior of papaya varieties and/or selections to the natural occurrence of target spot, and test the fungi toxic effect of neem, citronella and eucalyptus extracts, and fungi static effects of Bacillus isolates on the fungus C. cassiicola in vitro. To evaluate the natural occurrence of the disease in field, symptoms on leaves of 11 papaya varieties and/or selections have been assessed. The pathogenicity of isolates was verified by inoculation of plants in greenhouse. Neem, citronella and eucalyptus extracts were prepared at concentrations of 10, 15 and 20% and poured into Petri dishes containing C. cassiicola mycelium discs. For , Bacillusnine isolates were used, and the antagonistic potential was evaluated by the pairing of pathogen and isolate colonies by the circle method. Papaya varieties and/or selections presented all leaves with injury, and Canaan Sunrise Solo and Canaan Golden selections showed the greatest number of injuries per leaf, showing that papaya varieties and/or selections respond differently to the phytopathogen. All plant extracts tested showed inhibitory effect on the mycelial growth of C. cassiicola in vitro. Bacillus isolates showed an antagonistic potential on the mycelial growth of the fungus, with B. methylotrophicus (Iso 31 and Iso 41) being the most promising as a biological control agent. The results indicate that forms of alternative control of diseases are promising in the management of papaya target-spot.