Phytophthora megakarya, a causal agent of black pod rot in Africa

Cacao Diseases: A History of Old Enemies and New Encounters

Volumn , Issue , 2016, Pages 267-303

  Bailey, Bryan A ^a   Ali, Shahin S ^a   Akrofi, Andrews Y ^b   Meinhardt, Lyndel W ^a  

^a AGRICULTURAL RESEARCH SERVICE   (United States)

^b New Tafo   (Ghana)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84978208774     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.1007/978-3-319-24789-2_8     Document Type: Chapter

References (116)

1. Addo-Fordjour, P., Gyimah Gyamfi, H., Fei-Baffoe, B., & Akrofi, A. Y. (2013). Impact of copperbased fungicide application on copper contamination of cocoa plants and soils in the Ahafo Ano North District, Ashanti region, Ghana. Ecology, Environment and Conservation, 19(2), 303-310.
2. Aikpokpodion, P., Lajide, L., & Aiyesanmi, A. (2010). Heavy metals contamination in fungicide treated cocoa plantations in Cross River state, Nigeria. American-Eurasian Journal of Agricultural and Environmental Sciences, 8, 268-274.
3. Akrofi, A. (2015). Phytophthora megakarya: A review on its status as a pathogen on cacao in West Africa. African Crop Science Journal, 23(1), 67-87.
4. Akrofi, A. Y., Amoako-Atta, I., Assuah, M., & Asare, E. K. (2015). Black pod disease on cacao (Theobroma cacao, L) in Ghana: Spread of Phytophthora megakarya and role of economic plants in the disease epidemiology. Crop Protection, 72, 66-75.
5. Akrofi, A. Y., Govers, F., Awuah, R. T., & Raaijmakers, J. M. (2012). Exploiting microbial diversity in cocoa ecosystems in Ghana to control Phytophthora pod rot disease. Global Advanced Research Journal of Agricultural Science, 1(10), 305-308.
6. Akrofi, A., & Opoku, I. (2003). Phytophthora invasion of cocoa pod and bean. Journal of the Ghana Science Association, 5(1), 8-14.
7. Ali, S. S., Amoako-Attah, I., Bailey, R. A., Strem, M. D., Schmidt, M., Akrofi, A. Y., Surujdeo- Maharaj, S., Kolawole, O. O., Begoude, B. A. D., ten Hoopen, G. M., Goss, E., Phillips-Mora, W., Meinhardt, L. W., & Bailey, B. A. (2016). PCR-based identification of cacao black pod causal agents and identification of biological factors possibly contributing to Phytophthora megakarya’s field dominance in West Africa. Plant Pathology (In press).
8. Appiah, A., Flood, J., Archer, S., & Bridge, P. (2004a). Molecular analysis of the major Phytophthora species on cocoa. Plant Pathology, 53(2), 209-219.
9. Appiah, A., Flood, J., Bridge, P., & Archer, S. (2003). Inter-and intraspecific morphometric variation and characterization of Phytophthora isolates from cocoa. Plant Pathology, 52(2), 168-180.
10. Appiah, A. A., Opoku, I. Y., & Akrofi, A. Y. (2004b). Natural occurrence and distribution of stem cankers caused by Phytophthora megakarya and Phytophthora palmivora on cocoa. European Journal of Plant Pathology, 110(10), 983-990.
11. Argout, X., Fouet, O., Wincker, P., Gramacho, K., Legavre, T., Sabau, X., Risterucci, A. M., Da Silva, C., Cascardo, J., & Allegre, M. (2008). Towards the understanding of the cocoa transcriptome: Production and analysis of an exhaustive dataset of ESTs of Theobroma cacao L. generated from various tissues and under various conditions. BMC genomics, 9, 512.
12. Arnold, A. E., & Herre, E. A. (2003). Canopy cover and leaf age affect colonization by tropical fungal endophytes: Ecological pattern and process in Theobroma cacao (Malvaceae). Mycologia, 95(3), 388-398.
13. Asare-Nyako, A. & Bruce, R. (1982-1985). Cocoa Research Institute of Ghana Annual Report. In Report of the Cocoa Research Institute of Ghana, 1982/83-1984/85Tafo, Ghana.
14. Awuah, R., & Frimpong, M. (2007). Investigation into the seed-borne nature and seed to seedling transmission of Phytophthora in cocoa. Journal of Science and Technology (Ghana), 27(1), 9-16.
15. Bae, H., Bowers, J. H., Tooley, P. W., & Bailey, B. A. (2005). NEP1 orthologs encoding necrosis and ethylene inducing proteins exist as a multigene family in Phytophthora megakarya, causal agent of black pod disease on cacao. Mycological Research, 109(12), 1373-1385.
16. Bailey, B. A., Bae, H., Strem, M. D., de Mayolo, G. A., Guiltinan, M. J., Verica, J. A., Maximova, S. N., & Bowers, J. H. (2005). Developmental expression of stress response genes in Theobroma cacao leaves and their response to Nep1 treatment and a compatible infection by Phytophthora megakarya. Plant Physiology and Biochemistry, 43(6), 611-622.
17. Bernhardt, E., & Grogan, R. (1982). Effect of soil matric potential on the formation and indirect germination of sporangia of Phytophthora parasitica, Phytophthora capsici, and Phytophthora cryptogea [Rots of tomatoes, Lycopersicon esculentum]. Phytopathology (USA), 72(5), 507-511.
18. Boccas, B. (1981). Interspecific crosses between closely related heterothallic Phytophthora species. Phytopathology, 71(1), 60-65.
19. Boudjeko, T., Djocgoue, P., Nankeu, J., Mbouobda, H., Omokolo, D., & El Hadrami, I. (2007). Luteolin derivatives and heritability of resistance to Phytophthora megakarya in Theobroma cacao. Australasian Plant Pathology, 36(1), 56-61.
20. Brasier, C. (1969). Formation of oospores in vivo by Phytophthora palmivora. Transactions of the British Mycological Society, 52(2), 273-279.
21. Brasier, C., & Griffin, M. (1979). Taxonomy of ‘Phytophthora palmivora’ on cocoa. Transactions of the British Mycological Society, 72(1), 111-143.
22. Brasier, C., Griffin, M. & Maddison, A. (1981). The Cocoa black pod Phytophthoras. In P. Gregory & A. Maddison (Eds.), Epidemiology of Phytophthora on cocoa in Nigeria. Final report of the International Cocoa Black Pod Research Project, Vol. Phytopathological paper 25, 18-30. Kew Surrey, England: Commonwealth Mycological Institute.
23. Chee, K. (1973). Production, germination and survival of chlamydospores of Phytophthora palmivora from Hevea brasiliensis. Transactions of the British Mycological Society, 61(1), 21-26.
24. Cheesman, E. (1927). Fertilization and Embryogeny in Theobroma cacao, L. Annals of Botany, 1, 107-126.
25. Cilas, C. (2006). Comparison of resistance to Phytophthora pod rot in a ring test using leaf disc inoculation at ten sites. Global Approaches to Cocoa Germplasm Utilization and Conservation, pp. 116-123
26. Cooke, D., Drenth, A., Duncan, J., Wagels, G., & Brasier, C. (2000). A molecular phylogeny of Phytophthora and related oomycetes. Fungal Genetics and Biology, 30(1), 17-32.
27. CRIG (1979-1994). Cocoa Research Institute of Ghana annual reports. In Report of the Cocoa Research Institute of Ghana, 1979-1994 Tafo, Ghana.
28. CRIG (1990-1991). Cocoa Research Institute of Ghana Annual Report. In Report of the Cocoa Research Institute of Ghana, 1990/91, 59-85 Tafo, Ghana: Cocoa Research Institute.
29. Cunningham, R., & Arnold, P. (1962). The shade and fertiliser requirements of cacao (Theobroma cacao) in Ghana. Journal of the Science of Food and Agriculture, 13(4), 213-221.
30. Dakwa, J. (1974). The occurrence of Phytophthora palmivora (Butl) Butl in soil in Ghana. Ghana Journal of Agricultural Science, 7, 37-41.
31. Dakwa, J. (1979-1982). Cocoa Research Institute of Ghana Annual Report. In Report of the Cocoa Research Institute of Ghana, 1979/80-1981-82, 165-167, Tafo, Ghana.
32. Dakwa, J. (1984). Nationwide black pod survey. Joint CRIG/Cocoa Production Division Project. In Annual Report of the Cocoa Research Institute, Ghana, 1976/77-1978/79, p. 263 Tafo (Akim Abuakwa), Ghana: Cocoa Research Institute.
33. Dakwa, J. (1987). A serious outbreak of black pod disease in a marginal area of Ghana. In Proceedings of the 10th International Cocoa Research Conference, pp. 447-451.
34. Dakwa, J. (1988). Changes in the periods for attaining the cocoa black pod disease infection peaks in Ghana. In Proceedings of the 10th International Cocoa Research Conference, Santo Domingo, Dominican Republic, pp. 427-436.
35. deAlmeida, A., & Valle, R. (2007). Ecophysiology of the cacao tree. Brazilian Journal of Plant Physiology, 19(4), 425-448.
36. Deberdt, P., Mfegue, C., Tondje, P., Bon, M., Ducamp, M., Hurard, C., Begoude, B., Ndoumbe-Nkeng, M., Hebbar, P., & Cilas, C. (2008). Impact of environmental factors, chemical fungicide and biological control on cacao pod production dynamics and black pod disease (Phytophthora megakarya) in Cameroon. Biological Control, 44(2), 149-159.
37. Dennis, J. & Konam, J. (1993). Phytophthora palmivora cultural control methods and their relationship to disease epidemiology on cocoa in Papua New Guinea. In Proceedings of the 11th international cocoa research conference, pp. 18-24.
38. Dick, M. (2001). Straminipilous fungi: Systematics of the peronosporomycetes including accounts of the marine straminipilous protists, the plasmodiophorids and similar organisms, pp. 1-660.
39. Djiekpor, E., Goka, K., Lucas, P., & Partiot, M. (1981). Cocoa black pod rot caused by Phytophthora sp. in Togo: Assessment and control strategies. Cafe Cacao The, 25(4), 263-268.
40. Djiekpor, E., Partiot, M. & Lucas, P. (1982). Cacao black pod caused by Phytophthora sp. in Togo: Determination of causal species. In Proceedings 8th International Cocoa Research Conference, Cartagena, Colombia, 18 23 Oct 1981, pp. 473-478. Cocoa Producers’ Alliance.
41. Djocgoue, P., Boudjeko, T., Mbouobda, H., Nankeu, D., El Hadrami, I., & Omokolo, N. (2007). Heritability of phenols in the resistance of Theobroma cacao against Phytophthora megakarya, the causal agent of black pod disease. Journal of Phytopathology, 155(9), 519-525.
42. Djocgoue, P. F., Mbouobda, H. D., Boudjeko, T., Effa, P. O., & Omokolo, D. N. (2012). Amino acids, carbohydrates and heritability of resistance in Theobroma cacao/Phythophtora megakarya interaction. Phytopathologia Mediterranea, 50(3), 370-383.
43. Drenth, A. & Sendall, B. (2001). Practical guide to Detection and identification of Phytophthora. 1.0, pp. 1-41.
44. Efombagn, M., Marelli, J., Ducamp, M., Cilas, C., Nyasse, S., & Vefonge, D. (2004). Effect of fruiting traits on the field resistance of cocoa (Theobroma cacao L.) clones to Phytophthora megakarya. Journal of Phytopathology, 152(10), 557-562.
45. Erselius, L. J., & Shaw, D. (1982). Protein and enzyme differences between Phytophthora palmivora and P. megakarya: Evidence for self-fertilization in pairings of the two species. Transactions of the British Mycological Society, 78(2), 227-238.
46. Evans, H. (1971). Transmission of Phytophthora pod rot of cocoa by invertebrates. Nature, 232, 346-347.
47. Ferguson, A., & Jeffers, S. (1999). Detecting multiple species of Phytophthora in container mixes from ornamental crop nurseries. Plant Disease, 83(12), 1129-1136.
48. Ferrin, D. M., & Mellinger, H. C. (1977). Control of Phytophthora wilt of azaleas with CGA 48988. Proceedings of the Florida State Horticultural Society, 90, 333-336.
49. Fo, H., Oudemans, P., & Coffey, M. D. (1990). Mitochondrial and nuclear DNA diversity within six species of Phytophthora. Experimental Mycology, 14(1), 18-31.
50. Gisi, U., Zentmyer, G., & Klure, L. (1980). Production of sporangia by Phytophthora cinnamomi and P. palmivora in soils at different matric potentials. Phytopathology, 70(4), 301-306.
51. Gregory, P., Griffin, M., Maddison, A., & Ward, M. (1984). Cocoa black pod: A reinterpretation. Cocoa Growers’ Bulletin, 35, 5-22.
52. Gregory, P. H., & Maddison, A. (1981). Epidemiology of Phytophthora on cocoa in Nigeria. Phytopathological Paper, 25, 23-26.
53. Gunderson, J. H., Elwood, H., Ingold, A., Kindle, K., & Sogin, M. L. (1987). Phylogenetic relationships between chlorophytes, chrysophytes, and oomycetes. Proceedings of the National Academy of Sciences, 84(16), 5823-5827.
54. Hislop, E. (1963). Studies on the chemical control of Phytophthora palmivora (Butl.) Butl. on Theobroma cacao L. in Nigeria. Annals of Applied Biology, 52(3), 465-480.
55. Hislop, E., & Park, P. (1962). Studies on the chemical control of Phytophthora palmivora (Butl.) Butl. on Theobroma cacao L. in Nigeria. Annals of Applied Biology, 50(1), 77-88.
56. Holmes, K., Evans, H., Wayne, S., & Smith, J. (2003). Irvingia, a forest host of the cocoa blackpod pathogen, Phytophthora megakarya, in Cameroon. Plant Pathology, 52(4), 486-490.
57. Ivors, K., Garbelotto, M., Vries, I., Ruyter-Spira, C., Hekkert, B., Rosenzweig, N., & Bonants, P. (2006). Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations. Molecular Ecology, 15(6), 1493-1505.
58. Iwaro, A., Sreenivasan, T., & Umaharan, P. (1997a). Foliar resistance to Phytophthora palmivora as an indicator of pod resistance in Theobroma cacao. Plant Disease, 81(6), 619-624.
59. Iwaro, A., Sreenivasan, T., & Umaharan, P. (1997b). Phytophthora resistance in cacao (Theobroma cacao): Influence of pod morphological characteristics. Plant Pathology, 46(4), 557-565.
60. Iwaro, A., Sreenivasan, T., & Umaharan, P. (1998). Cacao resistance to Phytophthora: Effect of pathogen species, inoculation depths and pod maturity. European Journal of Plant Pathology, 104(1), 11-15.
61. Kaosiri, T., & Zentmyer, G. A. (1980). Protein, esterase, and peroxidase patterns in the Phytophthora palmivora complex from cacao. Mycologia, 72, 988-1000.
62. Koné, Y. (1999). Etude de la structure actuelle des populations de Phytophthora spp., agents de la pourriture brune des cabosses du cacaoyer (Theobroma cacao L.) en Côte d’Ivoire. In DAA Thesis, Ecole Supérieure d’Agronomie, 111 Yamoussoukro, Côte d’Ivoire.
63. Kong, P., Hong, C., Richardson, P. A., & Gallegly, M. E. (2003). Single-strand-conformation polymorphism of ribosomal DNA for rapid species differentiation in genus Phytophthora. Fungal Genetics and Biology, 39(3), 238-249.
64. Kroon, L., Bakker, F., Van Den Bosch, G., Bonants, P., & Flier, W. (2004). Phylogenetic analysis of Phytophthora species based on mitochondrial and nuclear DNA sequences. Fungal Genetics and Biology, 41(8), 766-782.
65. Kumi, M., Wolffhechel, H., Hansen, H., & Mathur, S. (1996). Seed transmission of Phytophthora in cacao. Seed Science and Technology, 24(3), 593-595.
66. Lanaud, C., Fouet, O., Clément, D., Boccara, M., Risterucci, A., Surujdeo-Maharaj, S., Legavre, T., & Argout, X. (2009). A meta-QTL analysis of disease resistance traits of Theobroma cacao L. Molecular Breeding, 24(4), 361-374.
67. Lee, S. B., & Taylor, J. W. (1992). Phylogeny of five fungus-like protoctistan Phytophthora species, inferred from the internal transcribed spacers of ribosomal DNA. Molecular Biology and Evolution, 9(4), 636-653.
68. Louise, N. W., Séverin, T. N., Raymond, F., Xavier, E. F., & Martine, D. (2011). Flavonoïd compounds synthesis by cocoa fruits (Theobroma cacao L.) in response to Phytophthora megakarya infection. Research Journal of Agriculture and Biological Sciences, 7(3), 335-342.
69. Luterbacher, M. C. & Akrofi, A. Y. (1994). The current status and distribution of Phytophthora megakarya in Ghana. In Proceedings of the XIth International Cocoa Research Conference, 29-35 Yamoussoukro, Côte d’Ivoire: Cocoa Producers Alliance, Lagos, Nigeria.
70. Maddison, A. & Griffin, M. (1981). Detection and movement of inoculum. Phytopathological Papers: 31-49.
71. Martin, F. N., & Tooley, P. W. (2004). Identification of Phytophthora isolates to species level using restriction fragment length polymorphism analysis of a polymerase chain reactionamplified region of mitochondrial DNA. Phytopathology, 94(9), 983-991.
72. McGregor, A. (1984). Comparison of cuprous oxide and metalaxyl with mixtures of these fungicides for the control of Phytophthora pod rot of cocoa. Plant Pathology, 33(1), 81-87.
73. McMahon, P. & Purwantara, A. (2004). 6.1 Phytophthora on cocoa. Diversity and Management of Phytophthora in Southeast Asia: 104-114.
74. Mfegue, C., Herail, C., Adreit, H., Mbenoun, M., Techou, Z., Ten Hoopen, M., Tharreau, D., & Ducamp, M. (2012). Microsatellite markers for population studies of Phytophthora megakarya (Pythiaceae), a cacao pathogen in Africa. American Journal of Botany, 99(9), e353-e356.
75. Motamayor, J. C., Lachenaud, P., da Silva e Mota, J. W., Loor, R., Kuhn, D. N., Brown, J. S., & Schnell, R. J. (2008). Geographic and genetic population differentiation of the Amazonian chocolate tree (Theobroma cacao L). PLoS One, 3(10), e3311.
76. Naganeeswaran, S. A., Subbian, E. A., & Ramaswamy, M. (2012). Analysis of expressed sequence tags (ESTs) from cocoa (Theobroma cacao L) upon infection with Phytophthora megakarya. Bioinformation, 8(2), 65-69.
77. Ndoumbe-Nkeng, M., Cilas, C., Nyemb, E., Nyasse, S., Bieysse, D., Flori, A., & Sache, I. (2004). Impact of removing diseased pods on cocoa black pod caused by Phytophthora megakarya and on cocoa production in Cameroon. Crop Protection, 23(5), 415-424.
78. Ndoumbe-Nkeng, M., Efombagn, M., Nyasse, S., Nyemb, E., Sache, I., & Cilas, C. (2009). Relationships between cocoa Phytophthora pod rot disease and climatic variables in Cameroon. Canadian Journal of Plant Pathology, 31(3), 309-320.
79. Ndoumou, D. O., Djocgoue, P., Nana, L., & Debost, M. (1995). Variation and inheritance of peroxidase activity and phenol and saccharide content in cacao in relation to susceptibility to black pod disease. Biologia Plantarum, 37(3), 429-436.
80. Ndoumou, O. D., Ndzomo, T. G., & Djocgoue, P. (1996). Changes in carbohydrate, amino acid and phenol contents in cocoa pods from three clones after infection with Phytophthora megakarya Bra. and Grif. Annals of Botany, 77(2), 153-158.
81. Nichols, R. (1961). Xylem occlusions in the fruit of cacao (Theobroma cacao) and their relation to cherelle wilt. Annals of Botany, 25(100), 463-475.
82. Nichols, R. (1964). Studies of fruit development of cacao (Theobroma cacao) in relation to cherelle wilt I. development of the pericarp. Annals of Botany, 28(4), 619-635.
83. Nwaga, D., Normand, M. I., & Citharel, J. (1990). Identification and differentiation of Phytophthora by electrophoresis of mycelial proteins and isoenzymes. EPPO Bulletin, 20(1), 35-45.
84. Nyadanu, D., Akromah, R., Adomako, B., Kwoseh, C., Lowor, S., Dzahini-Obiatey, H., Akrofi, A., Owusu Ansah, F., & Assuah, M. (2012). Histological mechanisms of resistance to black pod disease in cacao (Theobroma cacao L.). Journal of Plant Sciences, 7, 1-16.
85. Nyasse, S., Grivet, L., Risterucci, A., Blaha, G., Berry, D., Lanaud, C., & Despreaux, D. (1999). Diversity of Phytophthora megakarya in Central and West Africa revealed by isozyme and RAPD markers. Mycological Research, 103(10), 1225-1234.
86. Omokolo, N., Nankeu, D., Niemenak, N., & Boudjeko, T. (2003). Variation of b-1,3-glucanase, chitinase and polyphenoloxidase activities in cacao pods upon Phytophthora megakarya inoculation. In African Crop Science Journal, Vol. 11: African Crop Science Society.
87. Ondobo, M. L., Onomo, P. E., Djocgoue, P. F., Ndjaga, J. M., Boudjeko, T., & Ndoumou, D. O. (2014). Phenolic content and heritability of resistance in four hybrid populations of Theobroma cacao L. after leaves inoculation with Phytophthora megakarya Bras. et Grif. International Journal of Biological and Chemical Sciences, 8(1), 17-30.
88. Oome, S., Raaymakers, T. M., Cabral, A., Samwel, S., Böhm, H., Albert, I., Nürnberger, T., & Van den Ackerveken, G. (2014). Nep1-like proteins from three kingdoms of life act as a microbeassociated molecular pattern in Arabidopsis. Proceedings of the National Academy of Sciences, 111(47), 16955-16960.
89. Opoku, I., Akrofi, A., & Appiah, A. (2002). Shade trees are alternative hosts of the cocoa pathogen Phytophthora megakarya. Crop Protection, 21(8), 629-634.
90. Opoku, I., Appiah, A., Akrofi, A., & Owusu, G. (2000). Phytophthora megakarya: A potential threat to the cocoa industry in Ghana. Ghana Journal of Agricultural Science, 33(2), 237-248.
91. Opoku, I., Assuah, M., & Aneani, F. (2007). Management of black pod disease of cocoa with reduced number of fungicide application and crop sanitation. African Journal of Agricultural Research, 2(11), 601-604.
92. Panabieres, F., Marais, A., Trentin, F., Bonnet, P., & Ricci, P. (1989). Repetitive DNA polymorphism analysis as a tool for identifying Phytophthora species. Phytopathology, 79(10), 1105-1109.
93. Pokou, N., N’Goran, J., Eskes, A., & Sangaré, A. (2009). Cocoa farm survey in Côte d’Ivoire. In International Workshop on Cocoa Breeding for Farmers’ Needs, p. 26.
94. Sanogo, S., & Ji, P. (2013). Water management in relation to control of Phytophthora capsici in vegetable crops. Agricultural Water Management, 129, 113-119.
95. Sansome, E., Brasier, C., & Griffin, M. (1975). Chromosome size differences in Phytophthora palmivora, a pathogen of cocoa. Nature, 255, 704-705.
96. Sansome, E., Brasier, C., & Sansome, F. (1979). Further cytological studies on the ‘L’ and ‘S’ types of Phytophthora from cocoa. Transactions of the British Mycological Society, 73(2), 293-302.
97. Sanusi, R. & Oloyede, A. (2007). Shade management on cocoa farm in Nigeria: effect on pod production on on-station’s plots. In 8th African Crop Science Society Conference, Vol. 8, 1983- 1986 El-Minia, Egypt, 27-31 October 2007: African Crop Science Society.
98. Simo, C. D., Mboubda, P. F., Effa, H. D., Boudjeko, P. O., Ndiang, T. Z., & Omokolo, D. N. (2014). Assessing relationship between phenolic compounds and resistance to Phytophthora megakarya using two cocoa (Theobroma cacao) families. African Journal of Biotechnology, 13(29), 2956-2965.
99. Soberanis, W., Rıos, R., Arévalo, E., Zuniga, L., Cabezas, O., & Krauss, U. (1999). Increased frequency of phytosanitary pod removal in cacao (Theobroma cacao) increases yield economically in eastern Peru. Crop Protection, 18(10), 677-685.
100. Soh, P. T., Ndoumbè-Nkeng, M., Sache, I., Nguema, E. N., Gwet, H., & Chadoeuf, J. (2013). Development stage-dependent susceptibility of cocoa fruit to pod rot caused by Phytophthora megakarya. European Journal of Plant Pathology, 135(2), 363-370.
101. Sonwa, D. J., Coulibaly, O., Weise, S. F., Adesina, A. A., & Janssens, M. J. (2008). Management of cocoa: Constraints during acquisition and application of pesticides in the humid forest zones of southern Cameroon. Crop Protection, 27(8), 1159-1164.
102. Stassen, J. H., & Van den Ackerveken, G. (2011). How do oomycete effectors interfere with plant life? Current Opinion in Plant Biology, 14(4), 407-414.
103. Tchameni, S. N., Nwaga, D., Wakam, L. N., Ngonkeu, M., Leonard, E., Fokom, R., Kuaté, J., & Etoa, F. X. (2012). Growth enhancement, amino acid synthesis and reduction in susceptibility towards Phytophthora megakarya by arbuscular mycorrhizal fungi inoculation in cocoa plants. Journal of Phytopathology, 160(5), 220-228.
104. Ten Hoopen, G. M., Sounigo, O., Babin, R., Yede, Dikwe, G. & Cilas, C. (2011). Spatial and temporal analysis of a Phytophthora megakarya epidemic in a plantation in the centre region of Cameroon. In Proceedings of the 16th International Cocoa Research Conference, 16-21st November, 2009, pp. 683-687, Bali, Indonesia.
105. Thines, M. (2014). Phylogeny and evolution of plant pathogenic oomycetes-A global overview. European Journal of Plant Pathology, 138(3), 431-447.
106. Thorold, C. (1959). Methods of controlling black pod disease (caused by Phytophthora palmivora) of Theobroma cacao in Nigeria. Annals of Applied Biology, 47(4), 708-715.
107. Turner, P. (1960). Strains of Phytophthora palmivora (Butl.) Butl. From Theobroma cacao L.: I. isolates from West Africa. Transactions of the British Mycological Society, 43(4), 665-667.
108. Turner, P., & Asomaning, E. (1962). Root infection of Theobroma cacao by Phytophthora palmivora. Tropological Agriculture (Trinidad), 39, 339-343.
109. Urech, P., Schwinn, F. & Staub, T. (1977). CGA 48988 a novel fungicide for the control of late blight, downy mildews and related soil borne diseases. In Proceedings of the British Crop Protection Conference, Pests and Diseases, Vol. 1977, pp. 623-632.
110. Ward, M., & Griffin, M. (1981). Soil phase of cocoa Phytophthora. In P. H. Gregory & A. C. Maddison (Eds.), Epidemiology of Phytophthora on cocoa in Nigeria (Vol. 25, pp. 50-61). Kew: Commonwealth Mycological Institute.
111. West, J. (1936). Black pod of cocoa. Experimental control on native farms. In 11th Bulletin of Agricultural Department Nigeria, Vol. 11, pp. 1-11.
112. Wharton, A. L. (1958). Strains of Phytophthora palmivora occurring in Ghana and Nigeria. Report West African Cocoa research Institute, 1956-1957.
113. Widmer, T. L. (2014). Phytophthora palmivora. Forest Phytophthoras, 4(1), 3557.
114. Widmer, T. L. & Hebbar, P. K. (2013). Phytophthora megakarya. In Forest Phytophthoras, Vol. 3, p. 3386. Oregon State University.
115. Widmer, T. L., & Laurent, N. (2006). Plant extracts containing caffeic acid and rosmarinic acid inhibit zoospore germination of Phytophthora spp. pathogenic to Theobroma cacao. European Journal of Plant Pathology, 115(4), 377-388.
116. Yuen, J., & Andersson, B. (2013). What is the evidence for sexual reproduction of Phytophthora infestans in Europe? Plant Pathology, 62(3), 485-491.