scholarly journals Growth Inhibition of Cocoa Pod Rot Fungus Phytophthora palmivora byPseudomonas fluorescence and Bacillus subtilis bacteria

Author(s):  
Sakti Widyanta Pratama ◽  
Sri Sukamto ◽  
Lis Nur Asyiah ◽  
Yeni Vida Ervina

Black pod disease caused by Phytophthora palmivorafungus is one of the important diseases on cocoa crop. Pod rot is the most important disease because it may cause loss of cocoa pod. Until now, the fungal pathogen of cocoa black pod disease is still a crucial problem and there is no fungicide that is really effective against the disease. One alternative to control the cocoa black pod disease is by using biological agents as biofungicide, including utilizing Pseudomonas fluorescenceand Bacillus subtilis bacteria. The research was done by isolation of P. palmivora from infected pods of Kaliwining Experimental Station to obtain pure cultures of fungus and by multiplication of P. fluorescence and B. subtilis. Antagonist test was performed by inoculating P. palmivora into a petri dish in a distance of 3 cm from the edge. P. fluorescenceand B. Subtilis were inoculated into petridishes in three days after the fungal treatment. Control was inoculated with isolate of P. palmivora only. Fungal growth was measured everyday by measuring radius of fungal colonies first time 24 hours after inoculation. Growth of Phytophthora palmivora in the two treatmens were used to calculate the percentage of inhibition. The results of this study indicated that P. fluorescence and B. subtiliswere able to inhibit fungal growth of P. palmivora. Both bacterial antagonists had the same effectiveness in inhibiting the growth of P. palmivora fungus based on the percentage of inhibition and effectiveness criteria. Based on the results of translucent zones indicated that B. subtiliswas more powerfull in inhibiting growth of P. Palmivora compared to P. fluorescence. Key words: Black pod disease of cocoa, biological control, Phytophthora palmivora, Pseudomonas fluorescence, Bacillus subtilis

2012 ◽  
Vol 10 (3) ◽  
pp. 254-257
Author(s):  
Erwin Aragon ◽  
Claudia Rivera ◽  
Helena Korpelainen ◽  
Aldo Rojas ◽  
Paula Elomaa ◽  
...  

A total of 60 farmers' cacao accessions (Theobroma cacao L.) from Nicaragua were investigated using microsatellite markers to reveal their genetic composition and to identify potentially resistant genotypes against the black pod disease caused by Phytophthora palmivora. These accessions were compared with 21 breeders' accessions maintained locally, two Criollo accessions from Costa Rica and two accessions from Ecuador. The analyses showed a low level of differentiation among groups of farmers' accessions (FST = 0.06) and that six Nicaraguan accessions were genetically closely related to the two Criollo accessions used as a reference. In addition, seven distinct genotypes were found to have allelic composition that may indicate linkage to resistance alleles, thus being potential parental lines in future breeding programmes.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jennifer Decloquement ◽  
Roberto Ramos-Sobrinho ◽  
Samuel Galvão Elias ◽  
Dahyana Santos Britto ◽  
Alina Sandra Puig ◽  
...  

Black pod disease, caused by Phytophthora species, is among the main limiting factors of cacao (Theobroma cacao L.) production. High incidence levels of black pod disease have been reported in Brazil, being induced by Phytophthora capsici, Phytophthora citrophthora, Phytophthora heveae, and Phytophthora palmivora. To assess the diversity of Phytophthora species affecting cacao in Brazil, 40 new isolates were obtained from cacao pods exhibiting symptoms of black pod disease collected in different smallholder farms in 2017. Further, ten cacao-infecting isolates morphologically identified as P. citrophthora and P. palmivora were molecularly characterized. The genomic regions beta-tubulin, elongation factor 1 alpha, heat shock protein 90, and internal transcribed spacer, and the mitochondrially encoded cytochrome c oxidase I and II genes were PCR-amplified and Sanger-sequenced from the cacao-infecting Phytophthora isolates. The morphological characterization and evaluation of the mycelial growth rates for the Phytophthora isolates were performed in vitro. Based on the molecular analysis and morphological comparisons, 19 isolates were identified as P. palmivora (clade 4). Interestingly, 31 isolates grouped together in the phylogenetic tree and were placed apart from previously known species in Phytophthora clade 2. Therefore, these isolates are considered as a new species herein referred to as Phytophthora theobromicola sp. nov., which produced papillate, semipapillate, and persistent sporangia on simple sporangiophores. The P. palmivora isolates were identified as A1 mating type by pairing each isolate with known A1 and A2 tester strains of P. capsici, but no oogonia/antheridia were observed when P. theobromicola was paired with the different tester strains. The P. theobromicola and P. citrophthora isolates showed higher mycelial growth rates, when compared to P. palmivora, on different media at 10, 15, and 20°C, but similar values were observed when grown on clarified CA media at 25 and 30°C. The pathogenicity tests carried out on pods of four cacao clones (CCN51, PS1319, Cepec2004, and CP49) showed significant variability among the isolates of both Phytophthora species, with P. theobromicola inducing higher rates of necrotic lesion expansion, when compared to P. palmivora. Here, two Phytophthora species were found associated with black pod disease in the state of Bahia, Brazil, and the previously undescribed P. theobromicola seems to be prevalent in field conditions. This is the first report of P. theobromicola on T. cacao. Also, these findings are crucial to improve the disease control strategies, and for the development of cacao materials genetically resistant to Phytophthora.


2014 ◽  
Vol 1 (1) ◽  
pp. 41 ◽  
Author(s):  
Rita Harni ◽  
Efi Taufiq ◽  
Widi Amaria

<p>Penyakit utama busuk buah kakao disebabkan oleh Phytophthora palmivora dapat menurunkan hasil 20%-30%. Pengendalian penyakit<br />dengan fungisida nabati saat ini banyak dikembangkan, dengan tujuan mengurangi dampak negatif dari fungisida sintetik. Fungisida<br />nabati yang digunakan adalah minyak cengkeh dan serai wangi karena mudah didapat dan bersifat fungisidal. Penelitian bertujuan<br />menganalisis pengaruh formula fungisida nabati minyak cengkeh dan serai wangi terhadap perkembangan penyakit busuk buah kakao<br />(BBK) yang disebabkan oleh Phytophthora palmivora. Penelitian dilaksanakan di kebun petani Kabupaten Mamuju, Sulawesi Barat,<br />menggunakan rancangan acak kelompok 7 perlakuan, 4 ulangan. Setiap perlakuan diamati 20 buah kakao berukuran 8-10 cm.<br />Perlakuan yang diuji adalah 1) minyak cengkeh+serai wangi, 2) minyak cengkeh+asam salisilat, 3) minyak cengkeh+silikon, 4) serai<br />wangi+asam salisilat, 5) serai wangi+silikon, 6) fungisida sintetik sebagai pembanding, dan 7) kontrol. Larutan formula (5ml/liter)<br />disemprotkan pada buah setiap 2 minggu sekali sampai buah masak atau dipanen. Parameter yang diamati adalah persentase serangan,<br />intensitas serangan, kadar senyawa fenol, dan bobot biji kakao. Hasil penelitian menunjukkan bahwa formula fungisida nabati<br />cengkeh dan serai wangi yang diperkaya dengan asam salisilat dan silikon dapat menekan intensitas serangan penyakit busuk buah<br />kakao sebesar 20,48%-65,62%, tidak berbeda nyata dengan fungisida sintetik (73,15%). Besarnya tingkat penekanan penyakit sejalan<br />dengan kandungan senyawa fenol pada kuit buah kakao. Semakin tinggi kadar fenol pada kulit buah, maka semakin tinggi penekanan<br />penyakit busuk buah kakao. Penggunaan formula fungisida nabati dapat menekan kehilangan produksi kakao 23,94%-43,02%.<br />Formula terbaik dan dapat dianjurkan untuk pengendalian penyakit busuk buah kakao adalah minyak cengkeh+serai wangi,<br />cengkeh+asam salisilat, dan serai wangi+silikon.</p><p>Kata Kunci: Kakao, Phytophthora palmivora, busuk buah kakao, fungisida nabati</p><p>Black pod disease caused by Phytophthora palmivora is a major disease on cacao crops, which can cause yield losses until 20%-30%. Disease<br />control using botanical fungicide such as the use of clove and citronella oil, which have fungicidal effect, have been developed to reduce the negative<br />impact of synthetic fungicide residues. The objectives of this study was to analyze the effect of clove and citronella oil as botanical fungicide formula<br />on the development of black pod disease and seed weight of cocoa in the field. The study was carried out at farmer’s fields in Mamuju District, West<br />Sulawesi using a randomized block design with 4 replications and 7 treatment. In each treatment was observed 20 cacao pods with size 8-10 cm. The<br />treatments were 1) clove + citronella oil, 2) clove oil + salicylic acid, 3) clove oil + silicone, 4) citronella + salicylic acid, 5) citronella + silicone,<br />6) synthetic fungicides as a comparison treatment, and 7) control. The botanical formula was applied by spraying onto the entire surface of pod with<br />a concentration of 5 ml/litre every 2 weeks. Observations were include the percentage of attacks, intensity of the attack, the levels of phenolic<br />compounds, and seed weight of cacao. The results showed that the formula of botanical fungicide containing clove and citronella oil enriched with<br />salicylic acid and silicon can suppress disease attack of black pod (20.48%-65.62%), which was not significantly different from synthetic fungicide<br />(73.15%). The level of disease suppression in line with phenolic compounds of cocoa husk. In which, high phenolic contents can reduce black pod<br />disease at a higher level . The use of botanical fungicides formula can suppress the yield loss until 23.94% to 43.02%. The best formulas that can<br />be recommended in suppressing intensity of black pod disease were clove oil + citronella, clove oil + salicylic acid, and citronella + silicon.</p>


Author(s):  
Rian Arini ◽  
Gusti Ayu Kade Sutariati ◽  
Andi Khaeruni ◽  
Teguh Wijayanto ◽  
Novita Pramahsari Putri ◽  
...  

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.


2020 ◽  
Vol 16 (4) ◽  
pp. 172
Author(s):  
RUBIYO RUBIYO ◽  
AGUS PURWANTARA ◽  
SUDARSONO SUDARSONO

<p>ABSTRAK</p><p>Pemuliaan untuk menghasilkan klon yang toleran terhadap penyakitbusuk buah kakao sudah lama dilakukan di Indonesia. Pengendalian yangefektif dan efisien terhadap penyakit ini adalah dengan menggunakanbahan tanaman yang tahan. Tetapi untuk mendapatkan atau merakit bahantanaman yang tahan memerlukan waktu yang lama, juga ketersediaanplasma nutfah yang memiliki keragaman genetik yang tinggi. Penelitian inibertujuan untuk mengevaluasi respon koleksi kakao terhadap infeksipenyakit busuk buah P. palmivora. Kegiatan yang telah dilakukan adalahpengujian ketahanan 35 klon kakao terhadap infeksi P. palmivoraberdasarkan uji detached pod, dan menentukan ada tidaknya hubunganantara tipe kakao dan bentuk buahnya dengan sifat ketahanan terhadapinfeksi P. palmivora, serta kerentanan klon kakao terhadap infeksiP. palmivora pada koleksi plasma nutfah kakao. Penelitian dilakukan diLaboratorium Penyakit Pusat Penelitian Kopi dan Kakao Indonesia Jemberpada Tahun 2008. Penelitian ini menggunakan buah kakao dari 35 klonbuah 4 bulan setelah antesis. Buah yang dipetik dari pohon diinokulasidengan miselia P. palmivora di laboratorium. Pengamatan dilakukan ter-hadap panjang dan lebar bercak yang diakibatkan oleh infeksi P. palmi-vora terhadap buah kakao yang diuji. Berdasarkan hasil penelitiandiketahui bahwa klon kakao yang tahan terhadap penyakit busuk buah(P. palmivora) adalah klon ICCRI 1, PA 300, ICCRI 3, UIT 1, NIC 4, DR38, ICS 13, Sca 6, TSH 858 dan ICS 60 merupakan 10 klon kakao yangmempunyai tingkat resistensi tinggi terhadap infeksi P. palmivora dari 35plasma nutfah klon kakao yang diuji. Klon kakao yang sangat rentanadalah RCC 73, KKM 22, NIC 7, DRC 16, RCC 71, BL 300, BL 301,KEE 2, TSH 908 dan DRC 15. Klon kakao yang dapat digunakan sebagaitetua untuk proses seleksi lebih lanjut adalah: ICCRI 1, PA 300, ICCRI 3,UIT 1, TSH 858, NIC 4, DR 38, ICS 13, dan Sca 6.Kata kunci : Theobroma cocoa, kakao, busuk buah, evaluasi, plasmanutfah, uji ketahanan</p><p>ABSTRACT</p><p>Resistance of 35 Cocoa Clones against Phytophthorapalmivora Butl. Infection Based on Detached PODAssays</p><p>Breeding to produce clones tolerant to black pod disease of cocoahas long been done in Indonesia. Effective and efficient control of thisdisease is by using resistant planting material. But to obtain or assembleresistant planting materials require long period of time, also theavailability of germplasm with high genetic diversity. This researchactivities were conducted to evaluate the response of cocoa collectionagainst infection of black pod disease caused by Phytophthora palmivora.The objectives of this experiment were (i) to evaluate the respone of 35cocoa clones against infection of P. palmivora using detached pod assay,(ii) to determine the most resistance cocoa clones, and (iii) the mostsusceptible cocoa clones among evaluated cocoa germplasm collectionagainst infection of P. palmivora. The research was conducted at theDisease Laboratory of Indonesian Center for Coffee and Cocoa ResearchInstitute in 2008. In the experiment, pods of 35 cocoa clones (at 4-5months after anthesis) were harvested and inoculated with mycelia of P.palmivora in the laboratory. Observations were conducted on length andwidth of necrosed symptoms because of P. palmivora infection on thesurface of the tested pods. The experiment showed that ICRI 1, PA 300,ICRI 3, UIT 1, NIC 4, DR 38, ICS 13, TSH 858, SCA 6, and ICS 60 werethe ten most resistant cocoa clones. On the other hand, cocoa clones ofRCC 73, KKM 22, NIC 7, DRC 16, RCC71, BL 300, BL 301, KEE 2,TSH 908, and DRC 15 were the ten most susceptible cocoa clones.Genotypes used as the parental clones for future selection process wereclones: ICCRI 1, ICCRI 3, ICS 13, TSH 858, UIT 1, PA 300, NIC 4, DR38, and Sca 6.</p><p>Key words: Theobroma cocoa, cocoa, black pods, germplasm evaluation,resistance tests</p>


Author(s):  
Wael Alsultan ◽  
Ganesan Vadamalai ◽  
Halimi Mohd Saud ◽  
Ahmad Khairulmazmi ◽  
Mui Yun Wong ◽  
...  

Black pod, caused by Phytophthora spp., occurs worldwide and is a major problem to cocoa farmers in Malaysia. Limited studies addressed causal agents of black pod disease of cocoa in Malaysia as well as their genetic diversity. Therefore, this study was initiated to isolate and identify Phytophthora from the main cocoa plantations infected by black pod in Malaysia using sequence analyses of the ITS rDNA, EF-1α, and COX I gene regions. A total of 36 Phytophthora isolates were obtained from infected cocoa plantations from five states of Malaysia in 2016 and 14 isolates in 2013. Six Phytophthora isolates obtained from durian crop in 2013 were also used in this study. Results of phylogenetic analyses of combined dataset of the ITS rDNA, COX I and EF-1α confirmed that all Phytophthora isolates belonged to P. palmivora. P. palmivora isolates obtained from cocoa and durian clustered into different subclades based on the three regions examined. The study also examined the genetic diversity within a population of 56 P. palmivora isolates using random amplified polymorphic DNA (RAPD) and Inter-simple sequence repeat (ISSR) markers. The results of both markers indicated relatively high diversity among P. palmivora isolates. The complete separation was based on host and year of isolation. The study suggests that one species of Phytophthora viz. P. palmivora, is responsible for black pod of cocoa in Malaysia. However, the relatively high genetic diversity and separation of isolates into different clades may suggest that P. palmivora has been introduced into Malaysia via different sources.


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