Black Pod Rot Disease Research Articles

Botanical pesticide ability to control black pod rot of cacao Phytophthora palmivora (Butl.) Butl in the field

The use of synthetic chemical pesticides for cacao black pod rot disease control to remove heavy metal residues on cacao beans needs to be reduced. This research aimed to find out the ability of botanical pesticides to lower BPR incidence, BPR infection rate, and botanical pesticides’ efficacy in controlling BPR. It was conducted at the Cacao Research Substation Garden of the Plantation and Horticulture Office of Southeast Sulawesi. The treatments experimented included control (no pesticide), CNSE, CNSE + CSLS, CNSE + whiteflower albizia bark extract, CNSE + siam weed leaf extract, CNSE + candle bush leaf extract, CNSE + whiteflower albizia bark extract + siam weed leaf extract + candle bush leaf extract, and synthetic pesticide with active ingredient copper oxysulfate at 345 g/L. Group-randomized trial was used as design in triplicate. The research results showed that the botanical pesticides of CNSE, and the was mixture with of CSLS, siam weed leaf extract, candle bush leaf extract, and whiteflower albizia bark extract were able to lower the disease incidence and slow down the infection rate of BPR. The lowest BPR incidence and infection rates were discovered in the CNSE + Siam weed leaf extract treatment, each at 38.90% and 0.087 per pod per week. The CNSE botanical pesticide mixed with Siam weed leaf extract, whiteflower albizia bark extract, and candle bush leaf extract demonstrated good efficacy above 50%, hence feasible to use as an alternative to chemical pesticides in BPR control.

​Control Activity and Antibiotic Gene Detection of Endophytic Bacteria in Suppressing Cocoa Black Pod Disease (Phytophthora palmivora Butl.)

Background: Black pod rot disease of cocoa caused by (Phytophthora palmivora Butl.) is one of the major diseases on cocoa plantations worldwide. Many attempts have been made to prevent or reduce the infection of pathogens, but they have not provided optimum results. This study aims to detect antibiotic genes in endophytic bacteria that can suppress cocoa black pod disease. Methods: Eight endophytic bacteria were isolated from healthy cocoa pods and twigs that showed potentials in suppressing P. palmivora growth in vitro were used in suppressing of black pod rot disease in vivo tests. Antibiotic biosynthesis-related genes from eight endophytic bacterial isolates were confirmed by using PCR method, which includes phenazine-1-carboxylic (PCA), pyrrolnitrin (PRN), phenazine-1-carboxamide acid (PCN), pyoluteorin (PLT) and 2,4-diacetylphloroglucinol (DPAG/Phl). Result: The endophytic bacteria, 4RSI, 5BR B3 and 2RW B2 isolates showed the highest disease suppressing index to black pod rot disease in vivo, i.e., 70.27%, 70.08% and 56.64%. The isolates 5BR B3 and 2RW B2 DNA yielded PCR product by using PCA primers (1400 bp), PRN primers (700 bp) and DAPG primers (1600 bp), while the 5RSI isolate yield PCR product using PRN primers only. Endophytic bacterial isolates 5BRB3 and 2RW B2 provided partial disease suppression to pod rot disease by inhibit pathogen growth and antibiotic compounds production.

Observations on the Potential of an Endophytic Fungus Associated with Cacao Leaves against Phytophthora palmivora

A study was conducted to test the pathogenicity of an endophytic fungus associated with asymptomatic cacao leaves, to determine its identity through cultural, morphological and molecular characterization, and to evaluate itsantagonistic ability vs. Phytophthora palmivora causing cacao black pod rot disease. Experiments were carried out under laboratory and shade house conditions. Homogeneity of variances and normal data distribution were determined using Bartlett’s and Shapiro–Wilk tests, respectively. Inoculation of the endophyte in healthy cacao seedlings and pods at 5 × 105 to 1 × 106 conidia per mL by spraying resulted in asymptomatic infections. The endophyte was recovered from artificially inoculated tissues 14 and 26 days after inoculation (DAI) (UF18 seedlings), and at 10 (K9 seedlings) and 14 DAI from cacao pods. The endophyte was identified as Colletotrichum siamense based on its cultural, morphological and molecular characteristics. In vitroanti-pathogen assays showed that C. siamense had the potential to limit pathogen growth by antibiosis. At 3, 5 and 7 days after incubation period (DAIP), growth of the pathogen in co-cultivation with the endophyte measured 60.0, 70.0 and 71.0 mm, respectively, which wasconsiderably lower than the growth of the pathogen alone.

Spatial and Temporal Analysis of Phytophthora megakarya Epidemic in Newly Established Cacao Plantations.

Studying spatial and temporal plant disease dynamics helps us to understand pathogen dispersal processes and improve disease control recommendations. In this study, three cacao plots devoid of primary inoculum of Phytophthora megakarya (causal agent of cacao black pod rot disease) upon establishment in 2006 were monitored for presence of disease on a weekly basis from 2009 to 2016. Ripley's K(r) function, join count statistics, and Fisher's Exact test were used to analyze spatial and temporal disease dynamics. Disease distribution maps showed aggregated disease patterns in all plots; however, for the years of disease onset, exogenous primary infections were mostly randomly distributed. The K(r) function confirmed these results indicating that inoculum generally disperses only over short distances. Moreover, significant positive spatial autocorrelations showed that diseased trees were often clustered up to a distance of 3 to 9 m. Temporal disease progression was low, meaning that endogenous inoculum failed to establish itself, which is partly explained by rigorous phytosanitation and partly by unfavorable microclimatic conditions for disease development. Because P. megakarya had difficulty establishing itself in the plots, proximity to already infected cacao plantations drove infection dynamics. Thus, isolation of newly established cacao plantations from infected ones and rigorous phytosanitation as a preventive strategy appears to be an effective approach to control cacao black pod rot disease for newly established cacao plantations.

The expression of pathogenicity-related genes in Phytophthora palmivora causing black pod rot disease on cacao (Theobroma cacao L.) in Indonesia

ABSTRACT Phytophthora palmivora has a broad range of host plants. The expression of its pathogenicity-related genes in causing black pod rot disease on cacao in Indonesia has not been studied yet. This research was conducted to recognize relative expression of those genes using qPCR analysis. In planta experiment was carried out by inoculating representative three isolates on model plant (Nicotiana benthamiana) at the incubation periods of 24, 48, 72, and 96 h. The expressed genes were reconfirmed using conventional PCR and quantitatively analyzed using qPCR technique. The results showed that among eight target genes, four genes were actively expressed on the inoculated N. benthamiana, including CRN1, Pec1, Pec3, and RXLR5. Furthermore, qPCR analysis revealed that those genes were upregulated on the inoculated plants during incubation periods. In WNO1 and WAT1 isolates, the optimum expression was documented on the first day of incubation time, and then it was decreasing on the following days. However, the delay expression was exhibited by the pathogenicity-related genes in isolate BTG1. We assumed it as the general pathway of pathogenicity mechanisms in P. palmivora, since prior screening pathogenicity assay categorized that isolate BTG1 into moderate pathogenic, isolate WAT1 into high pathogenic, and isolate WNO1 into less pathogenic.

Antagonistic Potential of Endophytic Bacteria Against Phytophthora palmivora Causing Black Pod Rot Disease on Cacao (Theobroma cacao L.) In Indonesia

Background and Objective: The utilization of biological control agents using microorganisms is considered as one of the safest and most affordable strategies. This study was conducted to investigate the antagonistic potential of endophytic bacteria against Phytophthora palmivora causing black pod rot disease on cocoa in Indonesia. Materials and Methods: Endophytic bacteria were explored from healthy cocoa pods in Java, Sulawesi and Papua islands. Their antagonistic potential was screened using dual culture method. Bacterial isolates combating the growth of P. palmivora were grouped using rep-PCR technique (BOX1A, ERIC and REP primers). Their inhibition consistency was examined against P. palmivora using double layer technique. Histological assay on mycelial of pathogen was performed under SEM. The DNA of representative isolates was molecularly sequenced according to 16S rRNA and gyrB genes. The effectiveness of their antagonism under in vivo assay was observed on the P. palmivora-inoculated healthy cocoa pods. Results: The growth of P. palmivora was totally inhibited by 127 isolates. The clustering with rep-PCR assay revealed 12 groups of isolates which were independent on cacao clones, orchards and geographical origins. Several isolates showed the inhibition zone under double layer test. SEM viewed morphological abnormality as well as hyphal lysis, shrinking and wrinkling. The representative isolates were identified as members of Achromobacter, Alcaligenes, Bacillus, Burkholderia and Sphingobium genera. The optimum inhibition under in vivo experiment was exhibited by B. subtilis. Conclusion: The explored antagonists have possibility as alternative sustainable disease management strategy under appropriate formulation and application techniques as well as favourable environmental condition.

Phytophthora palmivora-Cocoa Interaction.

Phytophthora palmivora (Butler) is an hemibiotrophic oomycete capable of infecting over 200 plant species including one of the most economically important crops, Theobroma cacao L. commonly known as cocoa. It infects many parts of the cocoa plant including the pods, causing black pod rot disease. This review will focus on P. palmivora’s ability to infect a plant host to cause disease. We highlight some current findings in other Phytophthora sp. plant model systems demonstrating how the germ tube, the appressorium and the haustorium enable the plant pathogen to penetrate a plant cell and how they contribute to the disease development in planta. This review explores the molecular exchange between the oomycete and the plant host, and the role of plant immunity during the development of such structures, to understand the infection of cocoa pods by P. palmivora isolates from Papua New Guinea.

Isolation, identification and characterization of endophytic bacteria antagonistic to Phytophthora palmivora causing black pod of cocoa in Malaysia

Black pod rot is the most significant factor limiting production of cocoa (Theobroma cacao) in Malaysia with average annual losses of above 30%. This work was carried out to isolate, characterize and screen bacterial endophytes from cocoa plants for their biological control activities. Their mechanisms of action as well as abilities to reduce black pod rot disease were also investigated. In total, 103 endophytic bacterial isolates were obtained from healthy cocoa tissues (leaves, branches and fruits) from seven states of Malaysia in 2016 and screened for their antagonism against P. palmivora in vitro. The best two isolates AS1 and AS2 with more than 80% inhibition of radial growth (PIRG) were selected for subsequent experiments. Sequence analysis of the 16S rRNA region indicated that these two isolates belonged to Pseudomonas aeruginosa (AS1) and Chryseobacterium proteolyticum (AS2). Bioactive volatile compounds were identified using gas chromatography-mass spectrometry (GCMS). Major compounds present in P. aeruginosa extract were identified as Eicosane (9.11%), Hexatriacontane (6.87%), Tetratetracontane (5.17%), trans-2-Decenoic acid (17.04%) and 1-Phenanthrenecarboxylic acid, 1,2,3,4,4a,9,10,10a-octahydro-1,4a-dimethyl-7-(1-methylethyl) (3.60%). In C. proteolyticum extract, major compounds were identified as Eicosane (11.29%), Tetratetracontane (10.82%), Heneicosane (10.78%), Hexatriacontane (9.04%) and Phenol, 2,4-bis(1,1-dimethylethyl) (5.92%). Effectiveness of P. aeruginosa and C. proteolyticum in reducing black pod lesion was confirmed on detached cocoa pods with 100% inhibition for both isolates. These results indicated that these two bacterial isolates have potential to be used as bio-control agents against P. palmivora.

Endophytic Fungi with Potential as Biological Control Agents for Black Pod Rot Disease [Phytophthora palmivora (Butler) Butler

Production and cocoa plantation area in Indonesia decline every year, major causes is the outbreak of the cocoa black pod disease. Results showed that the antagonistic fungi found based on the DNA sequences are Lasiodiplodia euphorbicola, Diaporthe tectonae, Colletotrichum siamense, Aspergillus flavus, Candida parapsilogis, and Aspergillus sydowii. The results of the best inhibition shown by the endophytic fungus L. euphorbicola, thus passed field trials which showed that the higher the concentration of spore suspension the better the power suppress fungal antagonists against P. palmivora. The best concentration that colonies of the Petri dish was dissolved in 150 ml of sugar solution (10%).

Occurrence and distribution of black pod rot of Cocoa (Theobromae cocoa L.) in southern transition zone of Karnataka

Straminipile genus Phytophthora cause significant disease losses to global cocoa production. Phytopthtora palmivora is one of the major constraints in cocoa production causes significant pod losses. P. palmivora has a complex disease cycle involving several sources of primary inoculum and several modes of dissemination of secondary inoculum. This results in explosive epidemics during favorable environmental conditions. Highest severity of Seedling blight was observed in raised bed nurseries as compared to poly bag nurseries in Shivamogga district (59.26%) followed by Chikkamagluru (53.85%) of the state Karnataka , respectively. Further, the highest incidence of 72.00, 70.83 and 70.00% of black pod rot disease was recorded in Udupi, Dakshina Kannada and Shivamogga district followed by Chikkamagaluru (65.22%), Kodagu (64.00%) and Davanagere (55.56%) district respectively. Due to continuous rain fall or high moisture conditions and the crop was grown as intercrop with arecanut is vulnerable for the attack of pathogen due to the presence of pathogenic variability.

Application of lime and urea and its effect on development of Phythophthora palmivora.

Black pod rot disease (BPRD) which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

Endophytic fungal diversity in Theobroma cacao (cacao) and T. grandiflorum (cupuaçu) trees and their potential for growth promotion and biocontrol of black-pod disease

The endophytic niches of plants are a rich source of microbes that can directly and indirectly promote plant protection, growth and development. The diversity of culturable endophytic fungi from stems and branches of Theobroma cacao (cacao) and Theobroma grandiflorum (cupuaçu) trees growing in the Amazon region of Brazil was assessed. The collection of fungal endophytic isolates obtained was applied in field experiments to evaluate their potential as biocontrol agents against Phytophthora palmivora, the causal agent of the black-pod rot disease of cacao, one of the most important pathogens in cocoa-producing regions worldwide. The isolated endophytic fungi from 60 traditional, farmer-planted, healthy cacao and 10 cupuaçu plants were cultured in PDA under conditions inducing sporulation. Isolates were classified based upon the morphological characteristics of their cultures and reproductive structures. Spore suspensions from a total of 103 isolates that could be classified at least up to genus level were tested against P. palmivora in pods attached to cacao trees in the field. Results indicated that ∼70 % of isolates showed biocontrol effects to a certain extent, suggesting that culturable endophytic fungal biodiversity in this system is of a mostly mutualistic type of interaction with the host. Eight isolates from genera Trichoderma (reference isolate), Pestalotiopsis, Curvularia, Tolypocladium and Fusarium showed the highest level of activity against the pathogen, and were further characterized. All demonstrated their endophytic nature by colonizing axenic cacao plantlets, and confirmed their biocontrol activity on attached pods trials by showing significant decrease in disease severity in relation to the positive control. None, however, showed detectable growth-promotion effects. Aspects related to endophytic biodiversity and host–pathogen–endophyte interactions in the environment of this study were discussed on the context of developing sustainable strategies for biological control of black-pod rot of cacao.

Field Resistance of Cocoa (Theobroma cacao L.) Clones to Cocoa Pod Borer Infestation in Central Sulawesi

Black pod rot disease (BPRD) which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

Soil Nutrient Condition of Coffee Cultivation with Industrial Woody-crops

Black pod rot disease (BPRD) which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

Systemic Inducing Resistance on Cocoa Seedling Against Vascular Streak Dieback By Boron and Silikon Application

Black pod rot disease (BPRD) which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

Performance and suggested alternative strategies in developing Indonesian cocoa export business

Black pod rot disease (BPRD) which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia