Early detection of Phytophthora palmivora in oil palm, using real-time polymerase chain reaction (QPCR) and molecular beacon probesE. Álvarez (1), M. MARROQUÍN-GUZMAN (1), J. F. Mejía (1), J. M. Pardo (1)(1) Plant Pathology Program, Tropical Fruit Project, International Center for Tropical Agriculture (CIAT), Cali, Valle del Cauca, Colombia
Bud rot is considered the most limiting disease of oil palm in South America because it causes direct production losses on thousands of hectares dedicated to the crop. A Phytophthora sp. was isolated from commercial plantations cultivated in Ecuador, Brazil, and Colombia showing typical symptoms of bud rot. Pathogenicity was evaluated in 6- and 24-month-old palms under controlled conditions in the greenhouse and in leaf fragments placed in humidity chambers. Isolates of this Phytophthora sp. were found to be pathogenic on both 6 and 24-month-old palms, and Phytophthora sp. was re-isolated from infected tissue, therefore fulfilling Koch’s postulates. Through PCR, the causal agent was identified using A2/I2 primers specific to the genus Phytophthora, which amplified a 788-bp fragment located in the internal transcribed spacer (ITS) region. The PCR product was digested with the restriction enzymes MspI, RsaI, and TaqI, generating fragments that corresponded to P. palmivora. With the sequences obtained, molecular beacon probes and primers specific to the species were designed. This new method permitted timely, sensitive, and specific diagnoses of the pathogen in asymptomatic nursery plants, substrates, water, and possible vectors. Thus, studies on propagule distribution in soil and pathogen biology were made possible. As a result of this study, reliable decision-making tools for the integrated management of the disease could be developed to manage this disease.
New observations on the role of Lincus sp., in the transmission of sudden wilt (Marchitez sorpresiva) in oil palmM. Arango (1), B. Pineda (1), G. MARTINEZ (1)(1) Colombian Oil Palm Research Centre, Cenipalma, Bogota, Colombia
Sudden wilt (Marchitez sorpresiva) of oil palm has been associated with a protozoon of the genus Phytomonas (Trypanosomatidae), identified as P. staheli. The first symptoms of the disease include loss of fruit luster, followed by rotting of fruits and cessation of flowering. This is followed by foliar browning and desiccation beginning at the tips of the lower leaf leaflets and from the external end of the leaves, and advances upward into the crown in less than two months after first symptoms. There is also dead of the roots. Only mature, bearing palms develop symptoms in the field. There are some studies that indicate that the pathogen is transmitted by the Pentatomidae Lincus sp., but they do not indicate, clearly enough, the relationships between the vector, the pathogen and the palm. In this study, 15 five years old palms as well as 80 one year old nursery palms were inoculated with insects collected from diseased palms, 20 per palm in the adult ones and five in the young ones. As control there were used insects collect in an area free of this disease. They were kept on the experimental plants for 45 days. To recognize the presence of the pathogen associated with MS, the inoculated palms were evaluated 60, 100 and 300 days after the inoculation: In none of the inoculated palms it has been possible to observe symptoms of this disease or the presence of flagellated in the roots. It is necessary to get better information about the real role of Lincus sp., as vector of P. staheli in oil palm and if there are other Pentatomidae, Lygaeidae, or Coreidae insects, involved in this process. It is required to know more about the relationship between the vector and the pathogen in order to improve the control measures for this disease.
Phytopathogenic fungi of immature mango (Mangifera indica L.) fruitsL. BERRIOS (1), L. I. Rivera-Vargas (1)(1) Department of Crops and Agroenvironmental Sciences, College of Agricultural Sciences, University of Puerto Rico-Mayagüez Campus, Mayagüez, PR 00681
Colonization of immature mango fruits (mean = 1.6 cm) by phytopathogenic fungi is a key aspect of the production cycle. Their identification and description can lead to better disease control and management. Early ripeness, necrosis and soft rot are symptoms frequently observed in immature mango fruits in the field. Pathogenicity tests were conducted to determine the relative importance of phytopathogenic fungi isolated from symptomatic tissues of immature fruits. Healthy immature fruits were collected from mango cultivars Haden, Irwin, Parvin and Keitt at the Agricultural Experimental Station in Juana Díaz, Puerto Rico. The fruits were transported on ice to the laboratory, superficially disinfested and inoculated with a mycelial disc of axenic cultures of each fungal isolate. The following fungi were tested: Colletotrichum spp., Fusarium spp., Guignardia mangiferae, Phomopsis spp. and Botryosphaeria spp. Inoculation treatments consisted of fruits with and without wound including a non-inoculated control under laboratory conditions. Assays were examined in triplicates. After incubation at 25°C for 7 days, fruits were examined and fungi reisolated in acidified PDA. Ten fungal isolates caused necrosis and soft rots similar to those observed in the field with the exception of Botryosphaeria sp. (C isolate). Botryosphaeria spp. (D isolate) caused damage only in fruits with wounds suggesting the opportunistic strategy of this species. A better understanding of the diversity of phytopathogenic fungi colonizing mango fruits at early stages could lead to better prediction tools to diminish eventual damage of mature fruits.
Identification of Golovinomyces sp. in Acalypha wilkesiana using Scanning Electron Microscopy and other classification criteriaL. L. BONILLA (1), C. Estévez de Jensen (1), L. I. Rivera Vargas (1)(1) Department of Crops and Agro-Environmental Sciences, College of Agriculture, University of Puerto Rico, Mayagüez Campus, Mayagüez, PR 00681
Powdery mildews are obligate parasites of the Order Erysiphales, Phylum Ascomycota. These fungal pathogens are of great economic importance causing severe losses in the ornamental industry in Puerto Rico. Powdery mildews infect almost all ornamentals in greenhouses and gardens and appear as a white to grayish growth on leaves and young shoots. Acalypha wilkesiana (acalifa), from the Euphorbiaceae family, is a perennial shrub widely distributed in the Island and affected by powdery mildew. Observations using light and scanning electron microscope revealed ellipsoid, hyaline conidia borne single and terminally on the conidiogenic cell distinctive of Golovinomyces sp. Other morphological criteria examined were nipple shaped appressoria, absence of fibrosin bodies and amphigenous mycelium of the anamorphic stage. Measurements taken from primary conidia from infected tissue were on average 28.62 µm (length) × 14.01 µm (width). In addition, Amphelomyces quisqualis, a hyperparasite of powdery mildews, was identified in acalifa samples by sequence analysis of the ITS region of the ribosomal DNA.
Rhynchophorus palmarum and Strategus aloeus management in oil palm plants affected by bud rot disease in ColombiaH. GOMES DE OLIVEIRA (1), R. Aldana (1), O. Moya (1), G. Martínez (1)(1) Colombian Oil Palm Research Centre, Cenipalma, Bogota, Colombia
Bud rot disease in oil palm (Elaeis guineensis Jacq), is the most severe disease in Colombian and also in all tropical America where oil palm is cultivated. Specifically, in Colombian, bud rot disease has destroyed thousands of hectares. The situation is more severe because the presence of the insect Rhynchophorus palmarum (Coleoptera: Curculionidae) that is attracted by the plants affected by this disease. On these plants R. palmarum female lays its eggs and emerged larvae feed on the damaged plants. It avoids the recovery of plants affected by bud rot that normally dies by the cumulative effect of both negative factors. Another important issue is that R. palmarum acts as primary vector for red ring nematode, Bursaphelenchus cocophilus. Diseases occurrence, red ring and bud rot on oil palm plants had caused eradication of thousands of hectares, that result in the amount of plants stalks, where reproduces. At the same time Strategus aloeus (Coleoptera: Scarabidae), causes direct damage in the bulb in plants with less than four years in the field. It has been observed that there is a relation between S. aloeus and R. palmarum, where R. palmarum uses the galleries done by S. aloeus and also damages young plants. In this work we present activities that the Colombian Oil Palm Research Centre, Cenipalma- is developing, in the management and control of both insects. Among these activities are the developing of a integrated pest management based in R. palmarum trap, access of biological control for both coleopteran and study of new molecules that will permit specific pest control.
Identification of Oidium neolycopersici, a powdery mildew of tomato, using scanning electron microscopy (SEM) and DNA analysisE. LATONI-BRAILOWSKY (1), M. Vaz (1), L. I. Rivera-Vargas (1)(1) Department of Crops and Agroenvironmental Sciences, College of Agricultural Sciences, University of Puerto Rico, Mayagüez Campus, Mayagüez, Puerto Rico 00681
Tomato production in Puerto Rico is valued at $11 million per year. Powdery mildews (Ascomycetes, Order Erysiphales) are an important limiting factor in tomato production. Commonly, the foliage is covered with a profuse white-to-grayish growth, which often results in reduced yield. Recent research has established the existence of two powdery mildews species affecting tomato: Oidium lycopersici, restricted to Australia and O. neolycopersici, a newly described species of worldwide distribution. The objective of this research was to identify the Erysiphales attacking tomato in Puerto Rico. Tomato leaf samples with powdery mildew symptoms were field collected. Species determination was performed using both, light and scanning electron microscopy. In addition, PCR was used to amplify rDNA’s ITS region, followed by nucleotide sequencing. Criteria for species determination were conidial production and germination, shape of appresoria, presence or absence of fibrosin bodies, and fimbriate patterns of the conidial wall. Using these criteria, we can confirm the presence of the newly described O. neolycopersici infecting tomatoes in Puerto Rico.
New developments in the study of the causal agent of oil palm bud rot disease in ColombiaG. MARTINEZ (1), F. Varon (1), J. Rodriguez (1), H. Aya (1), D. C. Velez (1), Diana C. (1), S. Salcedo (1), C. Noreña (1), J. Ariza (1), F. Zuñiga (1), Y. Mestizo (1), G. A. Torres (1), and G. A. Sarria (1)(1) Colombian Oil Palm Research Centre, Cenipalma, Bogota, Colombia
Bud rot is being considered the most serious disease of oil palm not only in Colombia but also in neighbor countries. Even though the disease has been studied for more than 40 years in Central and South America, the causal agent remained unknown for many years. As the result of the work done by Cenipalma, it was possible to identify Phytophthora palmivora as the causal agent for this disease. The pathogenicity tests are an important tool in the evaluation of materials for its tolerance to the disease. The researchers at Cenipalma have been working in the development of a reliable test for this purpose. One of them has been the inoculation of very young spear leaflets under in vitro conditions. The other one has been the inoculation of nursery palms. This work describe the procedures and the results obtained in the pathogenicity tests, and complements the previous ones that made it possible to identify P. palmivora as the causal agent of bud rot in oil palm. In the in vitro tests it is possible to see the rapid colonization of the tissue by the pathogen and in the nursery palms it has been possible to obtain up to 100% infection. In both cases it has been possible to see the advance of the mycelium toward healthy tissue and the development of sporangia as well as the release of more zoospores for further infection. Having a reliable procedure for pathogenicity tests is a very interesting advance in the study of this disease, the confirmation of its causal agent, and the development of very useful tools for the new studies, that are required for the evaluation of different isolates and for the breeding activities oriented toward the identification of sources of partial resistance to this disease.
Early diagnosis, elimination of affected tissue and protection of surrounding palms: The key for control of Phytophthora palmivora, the causal agent of bud rot in oil palm in ColombiaG. MARTINEZ (1), F. Varon (1), J. Rodriguez (1), H. Aya (1), D. C. Velez (1), S. Salcedo (1), C. Noreña (1), J. Ariza (1), F. Zuñiga (1), Y. Mestizo (1), G. A. Sarria (1), G. A. Torres (1)(1) Colombian Oil Palm Research Centre, Cenipalma, Bogota, Colombia
Bud rot, produced by Phytophthora palmivora, is the most important disease of oil palm in all the production areas of Colombia. With the recognition of the first symptoms as necrotic lesions on the sides of the young spear leaves (youngest, unexpanded leaf), it has been possible to teach palm workers how to do early identification of infected palms and to proceed with a treatment for the removal of affected tissue. When a diseased palm is identified, there is an inspection to decide the best area to access the upper part of it and with a sharp chisel, previously prepared, it is eliminated the least number of mature leaves necessary to reach the affected tissue. This is removed below the area of advance of the lesions produced by P. palmivora. All the tools used and the boots of the workers are disinfected with a solution of sodium hypochlorite. The exposed tissue is protected with a paste prepared with a fungicide, a bactericide and an insecticide. The surrounding palms are treated with a cocktail of fungicide, bactericide and insecticide to protect them during several weeks, depending of the inoculum pressure in the area and the main environmental conditions. Plants in advanced stages of the disease are eradicated. Using this procedure it has been possible to reduce the impact of the disease not only under experimental conditions but also in commercial plots in different growing areas. Once it was known the disease agent, it was easier to develop the control measures that must be implemented as soon as possible, to avoid high incidences of this disease. This procedure is being implemented by many farmers in different affected areas, and whenever the procedure has been done correctly, and especially when it has been implemented with low incidences, the results have been very promising.
Preliminary observations on basal stem rot in oil palm in ColombiaY. Mestizo (1), F. Varon (1), J. Rodriguez (1), H. Aya (1), G. Sarria (1), G. MARTINEZ (1)(1) Colombian Oil Palm Research Centre, Cenipalma, Bogota, Colombia
Basal stem rot associated (BSR) with Ganoderma spp., and particularly G. boninense, has been considered one of the most important diseases in oil palm. In Malaysia and Indonesia it is responsible of big losses due to yield reduction and dead of infected palms. In Colombia in plots of some of states, each time it is more evident the presences of cases of basal stem rot in palms with the internal and the external symptoms of BSR. The purpose of this work was to identify the microorganisms involved in the development of the symptoms, in Indupalma, San Alberto, Cesar, in the Colombian Central growing region. There were selected 30 palms in an area with an incidence of 12%, eight of them with advanced crater, 11 with a small crater and 11 without crater, at the beginning of the experiment. The development of external symptoms were recorded during nine months and at the end there was recorded the internal ones. Besides, there were taken samples of the tissue in the front of advance of the rotting process to identify the microorganisms present. There was described the presence of the main external and internal symptoms. The microorganisms isolated were: Cladosporium cladosporioides. Curvularia sp., Curvularia affinis, Cochliobolus lunatus (anamorph Curvularia lunatus), Coprinopsis cinerea, Phlebia sp. Fusarium spp., Pythium sp., and unidentified species of Basidiomycetes and Dothidiomycetes. It is necessary to continue the work of identification and the pathogenicity tests of the isolates and to start the recognition of the presence of this disease problem in all the growing areas and to implement as soon as possible the control measures.
Molecular identification of microorganisms associated with oil palm bud rot diseaseM. NAVIA (1), H. M. Romero (1,2), J. Rodriguez (3), D. C. Velez (3), G. Martinez (3)(1) Biology and Breeding of Oil Palm Program, Physiology and Molecular Biology Section, Research Center of Oil Palm, CENIPALMA, Bogotá, Colombia; (2) Biology Department, National University, Bogotá, Colombia; (3) Healthy of Oil Palm Program, Phytopathology section, Research Center of Oil Palm, CENIPALMA, Bogotá, Colombia
Oil palm bud rot disease (BR) is the main limiting factor for the production of the crop in Colombia. The disease has been rapidly growing in the last few years with devastating effects in some of the producing zones in the country. BR is found in the different oil palm development stages from nursery stage to established palms in the field. For many years, several microorganisms have been associated with the disease, however Phythophthora palmivora Bult, is now recognized as the causing agent of the initial lesions that finally lead to the rotting process typical of BR. Nevertheless, it is clear that the symptoms associated with the disease involve other microorganisms besides P. palmivora. In order to identify fungi and oomycetes associated with the rotting process, isolates were obtained from BR affected palms collected in three producing zones in Colombia. Microorganisms were purified and then identified based on rDNA ITS region sequencing using ITS1 and ITS4 primers. ITS regions from 117 isolates were sequenced. Based on the sequencing results 35 species were identified, including 6 oomycete species (Phythophthora spp. and Phytium spp.), 16 ascomycetes and 13 basidiomycetes. The results showed the predominance of distinct associated species of Fusarium (F. solani, F. oxysporum, F. equiseti, Gibberella zeae and G. moniliformis), representing 38% of the identified isolates. Thielaviopsis paradoxa (7.7% predominance) and P. palmivora (4.3% predominance) were also present. New species of genus never found before associated with BR disease were also found, including some well recognized oil palm endophytes. Based on the results we are developing molecular tools for microorganism identification and BR diagnosis.
Applications of PCR-based techniques in the diagnostics of tropical plant pathogens(1) L. I. RIVERA-VARGAS(1) Professor, Department of Crops and Agroenvironmental Sciences, University of Puerto Rico-Mayagüez Campus, Mayagüez, Puerto Rico 00681
Molecular techniques based on the amplification of nucleic acids, such as Polymerase Chain Reaction (PCR), are routinely used in the diagnostic determinations of plant pathogens worldwide. Their advantage consists on their specificity, sensitivity, strength, consistency and speed, in contrast with traditional techniques. Application of PCR-based methods to plant pathology problems in tropical agrosystems has provided evidence that complements traditional techniques in the identification of important pathogens. Our experience using PCR-based techniques has allowed us to identify Colletotrichum spp. affecting mango leaves, flowers, immature fruits and peduncles in Florida and Puerto Rico. Recently, we have used analysis of rDNA ITS region to identify five fungal species belonging to the Botryosphaeriaceae occurring in tropical fruits inflorescences. In addition, the use of species-specific primers complements the identification of pathogenic vs. non-pathogenic Guignardia spp. We have identified G. mangiferae an endophyte commonly occurring in rambutan and mango fruits in Puerto Rico from G. citricarpa, an important pathogen of quarantine significance in citrus causing black spot occurring in other countries. Unfortunately, DNA sequence data are frequently not available to support accurate diagnoses of many tropical fungal pathogens species. Often, many species are new to science, or sequence data is not available, even for most described species. For example, Lasmenia spp., a pathogen of rambutan, we still have to morphologically characterize the pathogen, consult experts, and work on obtaining molecular data to submit to the GenBank. We expect that increased availability of reliable DNA sequence data for tropical fungal pathogens will make faster and more accurate identification possible.
Examining soilborne pathogens as causal agents of the decline of Torreya taxifoliaL. I. RIVERA-VARGAS (1), V. Negron-Ortiz (2)(1) Department of Crops and Agroenvironmental Sciences, University of Puerto Rico-Mayagüez Campus, Mayagüez, Puerto Rico 00681; (2) U.S. Fish and Wildlife Service, Panama City, FL
Torreya taxifolia Arn. is an evergreen conifer endemic to the slopes of the Apalachicola River in Florida and Georgia. Surveys suggested that T. taxifolia has lost at least 98.5% of its total population size since the early 1900s, causing that this species be federally listed as endangered. Given the lack of seed production in the wild, and potentially a decline due to a fungal disease, all population viability models predict extinction. To determine the potential importance of soil-borne pathogens associated with T. taxifolia, we conducted a systematic survey of soil-borne fungi. Twenty four individuals, showing different degrees of decline, were sampled at two different sites: Torreya State Park (TSP), Florida, and US Corps of Engineers (Corps) land tract in Decatur, Georgia. The TSP trees were smaller (89 cm h; 5 cm diam.) than the Corps trees (174 cm h; 10.6 cm diam.). In addition, root necrosis and stem cankers were observed in 46% of trees examined. A diverse fungal community was associated with declining trees. Twenty fungal genera were identified belonging to the Oomycetes, Zygomycetes, Ascomycetes, Basidiomycetes, and anamorphic fungi. Anamorphic fungi, Oomycetes and Zygomycetes were the dominant groups. The majority of the isolates were obtained from root tissue. Seventy five percent of isolates were obtained from the Corps trees. Soil inhabiting fungi and rhizosphere could play an important role in the decline of T. taxifolia and pathogenicity tests are crucial to finally demonstrate their role.
Control measures for lethal wilt in oil palm in ColombiaL. J. Sierra (1), R. Aldana (1), M. Arango (1), G. MARTINEZ (1)(1) Colombian Oil Palm Research Centre, Bogotá, Colombia
Lethal wilt is one of the emerging diseases of oil palm in the East and Central growing zones in Colombia. Its causal agent has not been identified, neither the way it is being disseminated in the field. There are some reports indicating the association with a phytoplasma, but it has not being proved with certainty. A similar disease was reported in the 1970s in Northeast Colombia. The first symptoms of the disease are loss of fruit luster, rotting of fruits and roots, followed by foliar browning and drying beginning in the lowest fronds, at the tips of the leaflets and from the external end of the leaves, and advances upward into the crown in less than two months after first symptoms. Only mature, palms develop symptoms in the field. In order to develop control measures and under the presumption that there is an insect involved in transmission of the disease and that the grasses present in the oil palm fields are competing with the palm for water and nutrients and also are substrates for insect breeding. It was implemented a management program with insect control, weed control or both, to identified the best control measures. After more than 30 months of observations it was possible to impact positively the spread of the disease with the control of the vector involved in this disease transmission. The control measures, similar to the ones implemented for a similar disease in the 1970s in Northeast Colombia, appear to be the procedure to follow for the management of ML. With this information there are new possibilities to continue the studies to identify the vector as well as its causal agent.
Witches'-broom in Guacimo (Guazuma ulmifolia, Sterculiaceae), a disease caused by a phytoplasma from the 16SrXV group in Costa RicaW. Villalobos (1), M. Martini (2), L. Garita (1), R. Osler (2), L. MOREIRA (1,3)(1) Centro de Investigación en Biología Celular y Molecular, Universidad de Costa Rica, 11501-2060, San José, Costa Rica; (2) Dipartimento di Biologia e Protezione delle Piante, Università di Udine, via delle Scienze 208, 33100 Udine, Italy; (3) Escuela de Agronomía, Universidad de Costa Rica, 11501-2060, San José, Costa Rica
Guacimo (Guazuma ulmifolia) trees showing witches’-broom (GWB), reduced leaf size, short internodes, general stunting, and no flower and fruit production were observed on side roads in North, Pacific and Central Western areas of Costa Rica. To determine the occurrence of phytoplasma infection in symptomatic trees, analyses based on transmission electron microscopy (TEM), nested-PCR (primers P1/16S-SR followed by R16F2n/R16R2), RFLP (AluI, HpaII, Tru1I and Tsp509I) and sequencing were performed. Phytoplasmas were observed in the sieve cells of symptomatic trees but not in healthy ones by TEM. The infection was confirmed by nested-PCR, generating amplicons (about 1.2 kb) from all DNA samples from symptomatic trees. The RFLP analysis showed identical patterns among GWB samples and indicated that this phytoplasma belonged to hibiscus witches’-broom group (16SrXV). The 16S rDNA sequence (1400 nt) obtained from two GWB phytoplasma strains, shared 98.8% similarity with ‘Candidatus Phytoplasma brasiliense’ (AF147708). The virtual RFLP pattern showed 95% similarity with subgroup 16SrXV-A (AF147708), suggesting that this strain may represent a new subgroup within 16SrXV group. This is the first report of a phytoplasma infecting the neotropical tree species G. ulmifolia, and the natural occurrence of a phytoplasma strain closely related to ‘Ca. P. brasiliense’ in Costa Rica.
Interactions between thrips and plant pathogenic fungi in mango inflorescencesE. J. ZAYAS GARCIA (1), I. Cabrera-Asencio (1), L. I. Rivera-Vargas (1)(1) Department of Crops and Agroenvironmental Sciences, University of Puerto Rico-Mayagüez Campus, Mayagüez, PR 00681
Despite the relative worldwide economic importance of mango (Mangifera indica L.), particularly in Puerto Rico, few studies have been conducted on fungal pathogens or on insect populations associated with inflorescences. Thrips (Order Thysanoptera) might cause damage by ovipositing in the panicle, feeding on flower tissues, thus destroying cells and causing open wounds, through which plant pathogenic fungi can enter. Several fungi have been associated with necrotic tissues in mango inflorescences. Our objective was to evaluate several alternative infestation methods that involve presence or absence of mango flower thrips and 12 different fungal species. Cultivar Irwin was used as it is commonly found in Puerto Rico. Fungal species were: Alternaria alternata, A. infectoria, Albonectria rigidiuscula, Botryosphaeria ribis, B. rhodina, B. dothidea, B. parva, Colletotrichum gloeosporioides, Fusarium moniliforme, Neofusicoccum mangiferae, Phoma sorghina, and Phomopsis longicolla. Disease severity for each fungal species was evaluated in inflorescences on the following treatments: 1) No thrips and fungal inoculation with artificial wound, 2) no thrips and fungal inoculation without artificial wounds, 3) infestation of inflorescences with thrips, and 4) fungi and thrips in the same inflorescence. Healthy inflorescences were used as controls. Treatments were evaluated at five and eight days after inoculation. The highest disease severity was observed in inflorescences inoculated with fungi with artificial wounds and inoculation of fungi with thrips infestation. Inflorescences treated with thrips and B. ribis, B. dothidea, B. rhodina, N. mangiferae, P. sorghina and P. longicolla caused up to 100% disease severity. Management strategies in the field should emphasize thrips and disease control to reduced flower and eventually mango fruit damage.
Get ALL the Latest Updates for ICPP2018: PLANT HEALTH IN A GLOBAL ECONOMY. Follow APS!