Phytophthora Spp Research Articles

Impact of fungal diseases on common box (Buxus sempervirens L.) vegetation in Turkey

In recent years, severe dieback of boxwood (Buxus sempervirens) has been observed in the many forests in Turkey. In this study, boxwood diseases were investigated in the forests and nurseries in the Marmara and Black Sea regions of Turkey. Nurseries and boxwood forests in the above-mentioned regions were visited and leaf, branch, and soil samples were collected from symptomatic plants. Eleven fungal genera were isolated from the samples and identified based on morphological characteristics and sequencing of the ITS region and other barcoding loci. The box blight pathogen, Calonectria pseudonaviculata sensu stricto was most frequently isolated from declining boxwood both in the forest and nurseries. When tested on detached box shoots, C. pseudonaviculata was also the most aggressive pathogen on both wounded and intact leaves. Pseudonectria buxi (anamorph Volutella buxi) caused weak symptoms but only on wounded leaves. Pestalotiopsis asiatica and Gnomoniopsis smitovilgyi also caused necrosis on young shoots and yellowing on leaves. Phytophthora nicotianae was detected in one nursery while P. plurivora in two and P. occultans in one locations in the forests in the Black Sea region. The findings show that the boxwood decline in Black Sea region of Turkey is mainly caused by C. pseudonaviculata but other pathogens may also play a role in the decline. Commonly grown boxwood varieties; B. sempervirens ‘Osmanli’, B. microphylla ‘Variegata’ and B. microphylla ‘Faulkner’ were found susceptible against box blight alone and mixed infections with Volutella blight while B. sempervirens ‘Rotundifolia’ was tolerant. These box varieties showed similar reactions against Phytophthora spp.

The Use of qPCR Reveals a High Frequency of Phytophthora quercina in Two Spanish Holm Oak Areas

The struggling Spanish holm oak woodland situation associated with Phytophthora root rot has been studied for a long time. Phytophthora cinnamomi is considered the main, but not the only species responsible for the decline scenario. This study verifies the presence and/or detection of Phytophthora species in two holm oak areas of Spain (southwestern “dehesas” and northeastern woodland) using different isolation and detection approaches. Direct isolation and baiting methods in declining and non-declining holm oak trees revealed Phytophthora cambivora, Phytophthora cinnamomi, Phytophthora gonapodyides, Phytophthora megasperma, and Phytophthora pseudocryptogea in the dehesas, while in the northeastern woodland, no Phytophthora spp. were recovered. Statistical analyses indicated that there was not a significant relationship between the Phytophthora spp. isolation frequency and the disease expression of the holm oak stands in the dehesas. Phytophthora quercina and P. cinnamomi TaqMan real-time PCR probes showed that both P. cinnamomi and P. quercina are involved in the holm oak decline in Spain, but P. quercina was detected in a higher frequency than P. cinnamomi in both studied areas. Thus, this study demonstrates that molecular approaches complement direct isolation techniques in natural and seminatural ecosystem surveys to determine the presence and distribution of Phytophthora spp. This is the first report of P. pseudocryptogea in Europe and its role in the holm oak decline should be further studied.

English

One hundred wheat (Triticum aestivum L.) accessions were selected on the basis of different geographical areas of Pakistan. Isolation and identification of seed born fungi were conducted according to standard blotter test and a total of five major seed borne fungi including Alternaria alternata, Aspergillus niger, Fusarium species, Drechslera species and Phytophthora species were isolated from the wheat seeds. The frequency of occurrence of these five seed born fungi was 49, 46, 42, 35, and 16%, respectively. Infection percentage varied from 0 to 90% in all 100 wheat accessions. Among the accessions, the highest infection (100%) of seed born fungi was recorded in 011185 and 011757 accessions while the lowest infection (10%) was recorded in 011415 accessions. Moreover, in accessions collected from Gilgit Baltistan and Azad Jammu Kashmir. Alternaria niger and Alternaria fusarium were dominant, while in Khyber Pakhtunkhawa province, A. niger was prevalent followed by A. alternata. In the case of Baluchistan province, the dominant seed born fungi was A. alternata followed by Drechslera spp. Similarly, in case of Punjab, the occurrence of A. alternata, Drechslera spp., Fusarium spp., and A. niger associated with seeds were similar. For accession collected from Sindh province, the dominant seed born fungi was A. niger and Drechslera spp. However, the Phytophthora spp. infection of wheat seeds accession of Baluchistan was the highest followed by wheat seeds accession collected from Gilgit Baltistan and AJK, Kpk and Punjab, whereas wheat seeds accessions collected from Sindh province were found to be free from Phytophthora spp. Key words: Bread wheat, screening, wheat germplasm, seed born fungi.

Triplex real-time PCR detection of three quarantine Phytophthora pathogens infecting Malus Miller

In order to develop a simultaneous and specific molecular detection of the three quarantine Phytophthora pathogens, Phytophthora hibernalis, Phytophthora cambivora and Phytophthora syringae that infect Malus Miller, three pairs of real-time PCR primers (PH-F/PH-R, PC-F/PC-R and PS-F/PS-R) and three probes (PH-Pr, PC-Pr and PS-Pr) labeled with HEX, FAM and ROX, respectively, were designed for P. hibernalis, P. cambivora and P. syringae by alignment analyses of enolase (Enol), ras-like protein Ypt1 and HSP90 gene sequences with other Phytophthora spp. Black Hole Quencher 1 (BHQ1) was used for P. hibernalis and P. cambivora and BHQ2 for P. syringae. Through the optimization of the reaction conditions, a triplex real-time PCR simultaneous detection for the three Phytophthora species infecting Malus Miller was developed. It could achieve simultaneous and specific detection with a sensitivity of 2 × 10−4, 2 × 10−4 and 2 × 10−2 ng/μL genomic DNA, respectively, for P. hibernalis, P. cambivora and P. syringae.

An Overview of Canadian Research Activities on Diseases Caused by Phytophthora ramorum: Results, Progress, and Challenges.

International trade and travel are the driving forces behind the spread of invasive plant pathogens around the world, and human-mediated movement of plants and plant products is now generally accepted as the primary mode of their introduction, resulting in huge disturbance to ecosystems and severe socio-economic impact. These problems are exacerbated under the present conditions of rapid climatic change. We report an overview of the Canadian research activities on Phytophthora ramorum. Since the first discovery and subsequent eradication of P. ramorum on infected ornamentals in nurseries in Vancouver, British Columbia, in 2003, a research team of Canadian government scientists representing the Canadian Forest Service, Canadian Food Inspection Agency, and Agriculture and Agri-Food Canada worked together over a 10-year period and have significantly contributed to many aspects of research and risk assessment on this pathogen. The overall objectives of the Canadian research efforts were to gain a better understanding of the molecular diagnostics of P. ramorum, its biology, host-pathogen interactions, and management options. With this information, it was possible to develop pest risk assessments and evaluate the environmental and economic impact and future research needs and challenges relevant to P. ramorum and other emerging forest Phytophthora spp.

GUGUR DAUN TANAMAN KARET AKIBAT PENYAKIT PHYTOPHTHORA SPP. DI PERKEBUNAN KARET JEMBER, JAWA TIMUR

Renteng and Banjarsari field is a part of PT. Perkebunan Nusantara XII, located in Jember with major commodity of rubber plant. Since December 2013, leaf fall occurred in Renteng field Afdeling Sidomulyo (year of planting 1996) and Banjarsari field Afdeling Karang Nangka (year of planting 1993). The study was conducted in January to March 2014. Identification of the leaf fall was used macroscopic, microscopic and continued with Koch's postulates. The results showed that yellowing of leaf that's accompanied by leaf fall in Afdeling Sidomulyo (year of planting 1996) and Afdeling Karang Nangka (year of planting 1993) caused pathogen Phytophthora spp. This study has been proved that Phytophthora spp. causes the leaf fall in Indonesia after the last report in 1977.

Anthraquinones and flavanols isolated from the vegetable herb Rumex abyssinicus inhibit motility of Phytophthora capsici zoospores

Many secondary metabolites derived from Rumex extracts exhibited potent activities against a panel of phytopathogens including those of Phytophthora spp. Phytochemical investigation of Rumex abyssinicus has led to the isolation of nine compounds, including one phenolic acid (1), five anthraquinones (2–6) and three flavanols (7–9). Compounds 1, 4, 6–9 are reported here from R. abyssinicus for the first time. The isolated compounds were evaluated for their inhibitory activity against zoospores of the oomycete phytopathogen Phytophthora capsici. Physcion (3) displayed strongest motility inhibitory activity with a MIC value of 15μgmL−1, and showed lytic activities against zoospores at 500μgmL−1.

Effects of temperature on germination of sporangia, infection and protein secretion by Phytophthora kernoviae

Phytophthora kernoviae is a pathogen on a wide range of plants, but little is known of optimal infection conditions. Rhododendron ponticum leaves were inoculated with six different isolates of P. kernoviae sporangia and incubated at different temperatures from 10 to 28 °C. After 1 week, lesion development and pathogen recovery were only observed from all isolates at 15 and 20 °C and a few isolates at 10 °C. In an experiment with temperatures ranging from 20 to 25 °C, lesion development and pathogen recovery on R. ponticum, Magnolia stellata and Viburnum tinus occurred consistently at 20 and 21 °C, was limited at 22 °C, and did not occur at 23 °C and above. There was no difference in sporangia and zoospore germination at 20–25 °C. In a temperature fluctuation experiment, the necrotic area of inoculated R. ponticum leaves increased with longer incubation at 20 °C and decreased with longer incubation at 24 °C. Crude extracts of secreted proteins from P. kernoviae cultures grown at 20 and 24 °C were compared to determine any effects of temperature on pathogenicity. When spot tested on R. ponticum leaves, crude protein suspensions from cultures grown at 20 °C induced necrosis, while proteins from cultures grown at 24 °C did not. Proteomic analysis confirmed that a 10 kDa protein secreted at both 20 and 24 °C shared sequence homology to the conserved domains of known elicitins of other Phytophthora spp. The protein secreted at 20 °C that was responsible for necrosis has not been identified.

Optimization of Baiting Bioassay for the Detection of Phytophthora Spp. From Infested Citrus Soils and Virulence Evaluation of the Recovered Isolates

Optimization of Baiting Bioassay for the Detection of Phytophthora Spp. From Infested Citrus Soils and Virulence Evaluation of the Recovered Isolates

Recovery of Phytophthora ramorum in plant tissue with mixed infections

This study was performed to investigate the frequency with which P. ramorum would be isolated from host tissue co-infected with P. ramorum as well as an indigenous Phytophthora species or P. kernoviae. Three separate experiments were tested in a similar manner using different combinations of pathogens and hosts. Overall for any of the individual experiments, very few segments did not have any growth of Phytophthora spp. For mixed infections of P. ramorum and P. kernoviae, a difference was observed between isolating both of the species and P. ramorum only on rhododendron. The data showed that P. ramorum or P. kernoviae will not be detected 29 or 12% of the time, respectively, in infected Rhododendron sp. Phytophthora kernoviae was not detected alone in mixed infections with P. ramorum on Pieris japonica. When two different P. ramorum isolates were co-inoculated individually with one P. citricola isolate, there was a significant difference between isolating P. ramorum and isolating both species. These results confirm that choice of host species used for baiting can strongly influence detection results. For example, if P. japonica were used for baiting in mixed infections, there is a 55% chance that P. kernoviae would not be detected. This study highlights the difficulty in being confident in isolating and identifying an individual Phytophthora sp. from host material when mixed infections are present, and emphasizes the importance of a large sample size in order to increase the chances to recover all possible different species in a mixed infection.

Development and Application of qPCR and RPA Genus- and Species-Specific Detection of Phytophthora sojae and P. sansomeana Root Rot Pathogens of Soybean.

Phytophthora root rot of soybean, caused by Phytophthora sojae, is one of the most important diseases in the Midwestern United States, and is estimated to cause losses of up to 1.2 million metric tons per year. Disease may also be caused by P. sansomeana; however, the prevalence and damage caused by this species is not well known, partly due to limitations of current diagnostic tools. Efficient, accurate, and sensitive detection of pathogens is crucial for management. Thus, multiplex qPCR and isothermal RPA (recombinase polymerase amplification) assays were developed using a hierarchical approach to detect these Phytophthora spp. The assays consist of a genus-specific probe and two species-specific probes that target the atp9-nad9 region of the mitochondrial genome that is highly specific for the genus Phytophthora. The qPCR approach multiplexes the three probes and a plant internal control. The RPA assays run each probe independently with a plant internal control multiplexed in one amplification, obtaining a result in as little as 20 mins. The multicopy mitochondrial genome provides sensitivity with sufficient variability to discern among different Phytophthora spp. The assays were highly specific when tested against a panel of 100 Phytophthora taxa and range of Pythium spp. The consistent detection level of the assay was 100 fg for the qPCR assay and 10 pg for the RPA assay. The assays were validated on symptomatic plants collected from Michigan (U.S.) and Ontario (Canada) during the 2013 field season, showing correlation with isolation. In 2014, the assays were validated with samples from nine soybean producing states in the U.S. The assays are valuable diagnostic tools for detection of Phytophthora spp. affecting soybean.

Early survival of Quercus ilex subspecies from different populations after infections and co‐infections by multiple Phytophthora species

Forests in Europe are threatened by increased diversity of Phytophthora species, but effects on trees of simultaneous infections by Phytophthora and ecological consequences of their coexistence are unknown. This study explored variation in early survival of Quercus ilex to Phytophthora infections and assessed interactions between Phytophthora species when trees were co‐infected. Three Phytophthora species (P. cinnamomi, P. gonapodyides and P. quercina), seeds from 16 populations of Q. ilex (ballota and ilex subspecies) and two infection times were used as sources of variation in two experiments. The influence of Phytophthora species, Q. ilex subspecies and populations on plant germination and survival were analysed using generalized linear mixed models and survival analysis techniques. Germination rates were not influenced by Phytophthora spp. (P = 0.194) but by the subspecies and populations of Q. ilex (P < 0.001). In Phytophthora‐infested soils, Q. ilex subsp. ilex germinated at higher rates than Q. ilex subsp. ballota. Plant survival was strongly influenced by Phytophthora species (P < 0.001), not by the subspecies and populations of Q. ilex. Seedling mortality was reduced and delayed if a less virulent Phytophthora species infected plants prior to infection by a more virulent Phytophthora species. The results help to explain oak decline syndrome and the lack of natural and artificial regeneration of Q. ilex forests. Lack of interspecific variability of early survival to Phytophthora spp. discourages direct sowing for artificial reforestation programmes. Large, thick seeds, giving plants rapid growth, are advantageous traits when soils are infested with Phytophthora spp.

Pythium, Phytophthora, and Phytopythium spp. Associated with Soybean in Minnesota, Their Relative Aggressiveness on Soybean and Corn, and Their Sensitivity to Seed Treatment Fungicides.

Pythium spp. cause seed decay, damping-off, and root rot in soybean and corn; however, their diversity and importance as pathogens in Minnesota are unknown. Our objectives were to identify the Pythium spp. present in Minnesota soybean fields, determine their aggressiveness on corn and soybean, and investigate their sensitivity to seed treatment fungicides. For identification, sequences obtained using internal transcribed space ITS4 and ITS1 primers were compared with reference sequences in the National Center for Biotechnology Information database. Seedling and soil samples yielded over 30 oomycete species. Aggressiveness was determined using two methods; a seed assay, which also examined temperature effects on aggressiveness, and a seedling assay. Of 21 species evaluated, seven Pythium spp. were pathogenic on both soybean and corn, reducing root growth by 20% or more while two Pythium and one Phytopythium spp. were pathogenic only on soybean. Aggressiveness of many isolates increased as temperature increased from 15°C to 25°C. The sensitivity of 10 pathogenic species to azoxystrobin, ethaboxam, mefenoxam, pyraclostrobin, or trifloxystrobin was tested. EC50 values for mefenoxam and ethaboxam were 10-2 of those to strobilurin fungicides. Pythium spp. in Minnesota are diverse and a significant cause of seedling disease on soybean and corn. Most Pythium spp. isolated in this study were more sensitive to mefenoxam and ethaboxam than to strobilurin fungicides.

Identification of the Dominant Genotypes of Phytophthora infestans in Canada Using Real-Time PCR with ASO-PCR Assays.

Phytophthora infestans, a pathogenic oomycete that is the causal agent of potato and tomato late blight, has devastating effects worldwide. The genetic composition of P. infestans populations in Canada has changed considerably over the last few years, with the appearance of several new genotypes showing different mating types and sensitivity to the fungicide metalaxyl. Genetic markers allowing for a rapid assessment of genotypes from small amounts of biological material would be beneficial for the early detection and control of this pathogen throughout Canada. Mining of the P. infestans genome revealed several regions containing single-nucleotide polymorphisms (SNP) within both nuclear genes and flanking sequences of microsatellite loci. Allele-specific oligonucleotide polymerase chain reaction (ASO-PCR) assays were developed from 14 of the 50 SNP found by sequencing. Nine optimized ASO-PCR assays were validated using a blind test comprising P. infestans and other Phytophthora spp. The assays revealed diagnostic profiles unique to each of the five dominant genotypes present in Canada. The markers developed in this study can be used with environmental samples such as infected leaves, and will contribute to the genomic toolbox available to assess the genetic diversity of P. infestans at the intraspecific level. For late blight management, early warning about P. infestans genotypes present in potato and tomato fields will help growers select the most appropriate fungicides and application strategies.

Distribution of Phytophthora spp. in Southern Texas Citrus Grove Soils

A soil survey was conducted in 61 citrus groves in South Texas to determine the Phytophthora spp. present and their population levels. The survey revealed the presence of Phytophthora in 59 locations, with P. citrophthora in 13 locations, P. nicotianae in 46, and P. palmivora not found. Soil plating assay and PCR was conducted to verify the different Phytophthora spp. We analyzed our data to find sites which showed counts of over 10 to 20 propagules/cm3, a value that is of concern. Accepted for publication 19 July 2016. Published 18 August 2016.

Evaluation of chemical products and a biological one to manage Phytophthora spp. In ‘salustiana’ orange grafted on sunki rootstock

Phytophthora spp., cuyo habitat es el suelo, esta presente en la mayoria de los huertos de citricos del mundo, causando perdidas que pueden oscilar entre 10 y 30%. Para reducir los danos ocasionados por esta enfermedad en plantaciones citricolas, se evaluaron productos quimicos y uno biologico. estudio, se llevo a cabo en la finca El Cuervo, ubicada en la vereda Juntas, municipio de Neira, Caldas, en un cultivo de naranjo variedad Salustiana, injertado sobre un patron Sunki de siete anos de edad, afectado por Phytophthora spp. Las unidades experimentales, se seleccionaron teniendo en cuenta dos grados de ataque de la enfermedad: arboles ligera y severamente afectados. Se emplearon nueve tratamientos aplicados al suelo y uno inyectado al tallo; se utilizo una planta por cada grado de ataque y cinco repeticiones, en un diseno completamente al azar, en arreglo factorial, donde los factores fueron los tratamientos y los grados de ataque de la enfermedad. Se evaluo numero de raices, peso seco de raices, numero de frutos y peso de frutos. mejor tratamiento fue fosetil + propamocarb inyectados al tallo, con un numero de raices 7,20, peso seco de raices de 28,54g, numero de frutos de 1.467,20 unidades/ha y un peso de frutos de 421,40kg/ha, resultados que hacen de fosetil + propamocarb, inyectados al tallo, una alternativa viable, para lograr la recuperacion progresiva del sistema radical de los naranjos, ligeramente afectados por Phytophthora spp.

Detection of Phytophthora ramorum in Nurseries and Forest Lands in California in 2004 to 2009.

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P. ramorum-specific real-time polymerase chain reaction (PCR), and nested PCR. Yearly percentages of infected samples ranged from 0.6 to 2.3%. Camellia spp., Rhododendron spp., Magnolia spp., Pieris spp., and Laurus nobilis tested positive the most frequently in the nurseries and Lithocarpus densiflorus, Umbellularia californica, and Quercus agrifolia tested positive most often from wild lands. Of the 118,410 samples isolated onto PARP media, 0.8% was identified as P. ramorum. Of 115,056 samples tested by ELISA, 5.9% tested positive for Phytophthora spp. Of the 6,520 samples tested by PCR, 12.4% tested positive for P. ramorum. The false-negative, positive, and internal control failure rates of the assays are discussed. After removing the seasonal effect of sampling strategy, isolation of the pathogen into culture was found to be seasonally dependent whereas detectability by PCR and ELISA was not. To our knowledge, this is the first evaluation of a regulatory testing program for a plant pathogen on this scale using standardized assays.

The Pectin Methylesterase Gene Complement of Phytophthora sojae: Structural and Functional Analyses, and the Evolutionary Relationships with Its Oomycete Homologs.

Phytophthora sojae is an oomycete pathogen that causes the disease known as root and stem rot in soybean plants, frequently leading to massive economic damage. Additionally, P. sojae is increasingly being utilized as a model for phytopathogenic oomycete research. Despite the economic and scientific importance of P. sojae, the mechanism by which it penetrates the host roots is not yet fully understood. It has been found that oomycetes are not capable of penetrating the cell wall solely through mechanical force, suggesting that alternative factors facilitate breakdown of the host cell wall. Pectin methylesterases have been suggested to be important for Phytophthora pathogenicity, but no data exist on their role in the P. sojae infection process. We have scanned the newly revised version of the annotated P. sojae genome for the presence of putative pectin methylesterases genes and conducted a sequence analysis of all gene models found. We also searched for potential regulatory motifs in the promoter region of the proposed P. sojae models, and investigated the gene expression levels throughout the early course of infection on soybean plants. We found that P. sojae contains a large repertoire of pectin methylesterase-coding genes and that most of these genes display similar motifs in the promoter region, indicating the possibility of a shared regulatory mechanism. Phylogenetic analyses confirmed the evolutionary relatedness of the pectin methylesterase-coding genes within and across Phytophthora spp. In addition, the gene duplication events that led to the emergence of this gene family appear to have occurred prior to many speciation events in the genus Phytophthora. Our results also indicate that the highest levels of expression occurred in the first 24 hours post inoculation, with expression falling after this time. Our study provides evidence that pectin methylesterases may be important for the early action of the P. sojae infection process.

Citrus phytophthora diseases: Management challenges and successes

Phytophthora spp. are present in nearly all citrus groves in Florida and Brazil and phytophthora-induced diseases, especially foot and root rot, have the potential to cause economically important crop losses. Disease-related losses due to root rot are difficult to estimate because fibrous root damage and yield loss are not always directly proportional. Challenges from phytophthora diseases have been addressed in both countries by enacting phytosanitary requirements for production of pathogen-free nursery trees in enclosed structures, propagated from indexed and certified pathogen-free sources, in conjunction with several other cultural management practices. In Florida groves, a statewide soil sampling program provides growers with soil propagule counts to estimate the damage that Phytophthora spp. are causing to fibrous roots. The results can be used along with rootstock tolerance, soils, topography, irrigation, and drainage to make a decision for the need to treat with fungicides in addition to modification of cultural managements. Huanglongbing (HLB), caused by the psyllidtransmitted bacterium Candidatus Liberibacter asiaticus (Las), was detected in Brazil and Florida in the mid-2000s. Given the increasing incidence of HLB and deterioration of root density due to Las damage, research experiences and current phytophthora data trends suggest the need for more comprehensive management of root health by reducing the impact of abiotic and biotic stresses, including the interaction with Phytophthora spp.

Trichoderma from Aceh Sumatra reduce Phytophthora lesions on pods and cacao seedlings

The cocoa tree, Theobroma cacao L., suffers large yield losses in Aceh Indonesia due to the disease black pod rot, caused by Phytophthora spp. Despite having the largest area under cacao production in Sumatra, farmers in the Aceh region have low overall production because of losses to insect pests and black pod rot. Trichoderma spp. were isolated from the roots and leaves of cacao trees and screened as potential biological control agents. Isolates used in the study were Trichoderma asperellum isolates T2 and T4, Trichoderma longibrachiatum isolates T15 and T16, and Trichoderma virens isolates T1 and Tv. T1, T2, T4, and Tv completely colonized and destroyed Phytophthora tropicalis and Phytophthora palmivora mycelium in precolonized plate assays. All six isolates reduced P. tropicalis, but none reduced the growth of P. palmivora in dual plate assays. Phytophthora growth was suppressed on MIN media amended with sterile heat inactivated Trichoderma culture filtrates, with Tv best suppressing growth of both Phytophthora spp. T. virens isolate Tv was the only isolate observed coiling around P. tropicalis mycelium and disrupted the formation of P. palmivora sporangia. Of all six isolates, only Tv reduced P. palmivora lesion expansion in a detached pod assay, reducing severity by 71%. Tv also reduced P. palmivora infection on seedlings when applied aerially at 1×106 and 1×108conidia/ml, by 19% and 59%, respectively. T. virens isolate Tv is a mycoparasite, antagonizes Phytophthora in a dual plate assay, and shows antibiosis against Phytophthora spp., suggesting that multiple modes of action contribute to its ability to limit Phytophthora lesion expansion on cacao pods and seedlings.