Much of the confusion about the risks involved with seed imports stems from an unclear presentation in some papers and reports of the real phytosanitary situation of the oil palm in America, and the indiscriminate use of common names for diseases of the crop.

Tropical America covers more than twelve million square kilometers, a vast territory, which harbors a tremendous diversity of ecosystems. Considering the enormous distances between countries, and their biotic wealth, generalizations may easily lead to erroneous conclusions.

ASD has produced seed for more than 50 years on the South Pacific coast of Costa Rica (Coto). This area is well suited to oil palm cultivation and is free from most of the phytosanitary problems so far described for the crop. ASD facilities at Coto are open to any one genuinely interested in understanding the seed production operation, including our competitors in the seed business.

Diseases such as Lethal Bud Rot (LBR), Sudden Wither (Marchitez Sorpresiva), Dry Bud Rot or Leaf Mottle (Mancha Anular), Fusarium Wilt and others mentioned in the literature have never been found at Coto.

Common names for diseases in the Americas may cause much confusion, particularly when expressed using elements of the local folklore. For example, Lethal Bud Rot, also known as Lethal Spear Rot or even Bud Rot is not the same as Lethal Yellowing, Sudden Wither or Common Spear Rot.

The names spear rot, bud rot and derivatives that include the word "lethal", have been used freely to refer to disorders in which the youngest leaves partially or completely rot and outer leaves remain green. No pathogen has been identified as the sole cause of these problems, but there are always environmental factors that have been determined as predisposing the plant to such disorders.

Spear rots are by no means endemic to America, not even those that could cause the death of the palm, since this sometimes occurs even with the most familiar of these rots, Common Spear Rot which has been found wherever oil palm is grown (Turner 1981). Furthermore, Lethal Bud Rot as known in some areas of Tropical America is not always lethal. Since no causal agent has been identified for any "Lethal Bud Rot", it is not possible to be sure, for example, that the "disease" found in Colombia and Ecuador (or even in different areas of the same country) is exactly the same.

Lethal Bud Rot and related disorders are present in some countries of Tropical America, but they do not have a generalized distribution in all oil palm producing areas (Spear Rot of Oil Palm in Tropical America 1990).

Hundreds of attempts through more than 30 years have failed to identify a pathogen as the primary cause of most spear rots, including Common Spear Rot, which is the oldest known of these disorders. Lethal Spear Rot has defied all attempts to identify a primary pathogen for more than 20 years. Similar failures pertain to the identification of a vector agent.

It is true that much progress has been achieved by partially identifying the genetic background conferring susceptibility to Crown Disease. (Blaak 1970). However, if Crown Disease and Common Spear Rot are, as they seem to be, associated, then we still do not know which organisms and under what circumstances they cause the spears to rot. Even for Crown Disease itself there is a strong non genetic component (predisposition) determining disease incidence (Turner 1981; Breure and Sebagjo 1991; Chinchilla et al., unpublished data).

Why is it that so many attempts by so many people have failed to associate Lethal Bud Rot with a known pathogen ? Could it be that there is no a primary pathogen involved, and LBR is more of a "decline" type of disorder, similar to those so commonly present in many forest species and some other commercial crops ? (Manion and Lachance 1992). Rotting of tissues would be caused only in stressed palms by opportunistic microorganisms. A successful inoculation and reproduction of symptoms using these microorganisms only would occur when the predisposing conditions are fully understood. Here again, what is important are not the microorganisms (which are mere opportunistics) but the conditions that predispose the plant to the attack. All attempts to pinpoint a single cause for such decline--type disorders will fail, such as has occurred for LBR. Under this scenario it is not surprising that LBR can not be seed transmitted.

Since detailed examination of LBR as a decline type problem of oil palm in Tropical America is a rather new idea, not much information has been accumulated so far. This is why we can not yet explain how identical symptoms do not occur in South East Asia for example, but there are many obvious differences in climate, soil and management which could give some answers.

Even though LBR has been an important problem in some areas, many of the stories about plantations being totally destroyed by the disease hide a story of mismanagement and the occurrence of other phytosanitary problems such as the Red Ring disease.

The common allegation is that the oil palm industry in the Americas has not developed due to the presence of LBR. This is untrue. The real causes have been political and social unrest, lack of investment capacity and political decision. Nowadays the industry is growing faster than in the last decade.

Sudden Wither, "Marchitez Sorpresiva" in Spanish, also known as Cedros Wilt and Hart Rot, is caused by the flagellate Phytomonas sp. (Dollet and López 1978) which is mainly transmitted by Lincus spp. of the Pentatomidae family (Perthius et al. 1985) and probably Euclerus sp. (Vickerman and Dollet 1992). In Central America, it has been found infecting oil palm only along the Northern Caribbean coast of Honduras, scattered in a few very small and concentrated areas. The same pattern is observed in the South American countries where this disease is present. Sudden Wither is not found even close to any seed producing area, and it is not seed--borne; a plant infected by Phytomonas will stop bunch development and rot all its bunches rather quickly, before other symptoms appear, making it impossible to collect viable seeds.

When this disease was first noticed in South America in the 60's, it did apparently cause serious losses, mainly because inappropriate control measures. Since then, knowledge has been accumulated for its effective management and its importance is nowadays much reduced. Actually, if very basic control practices are used, such as an early eradication of infected plants, Sudden Wither becomes a disease of secondary importance.

Leaf Mottle (Mancha Anular). Of unknown etiology, this disorder is found only in very small and restricted areas in some South American locations, normally attacking only young plants. This disease has never been reported further north than Colombia. A similar disease, perhaps the same one, is also reported in Ivory Coast where it is called Dry Bud Rot. There, Sogatella cubana and S. kolophon (Delphacidae) are the two known vectors (Renard and Quillec 1984; Renard and de Franqueville 1989a).

Red Ring is a problem of common occurrence in several countries of Tropical America. The disease is caused by the nematode Bursaphelencus (Rhadinaphelencus) cocophilus and is transmitted by the American Palm Weevil (Rhynchophorus palmarum) (Blair 1970), a species restricted to tropical America. Transmission of the nematode by other insects, including Metamasius hemipterus has not been proven in Costa Rica, even though intensive research has been done in this area (Chinchilla, unpublished data).This disease is the most common pathological problem in oil palm and coconut in the region, and the only disease of economic concern found in Costa Rica. ASD of Costa Rica developed an effective control program that reduced incidence of Red Ring by more than 90% (Chinchilla et al. 1993, Chinchilla et al., unpublished results). The pathogen is not seed--borne (Blair and Darling 1968; Blair 1970; Schuiling and Dither 1981; Griffith 1987), and all experimental attempts to infect very young oil palm plants have failed. The disease normally appears in the field after eight years, and in rare cases after four (Chinchilla 1992).

Fusarium Wilt (Vascular Wilt) caused by Fusarium oxysporum f. sp. elaeidis, is a real soil--borne pathogen (de Franqueville and Renard 1990). The risks of seed imports from areas where Fusarium Wilt is present should be taken seriously. It has been demonstrated that under poor seed management, F. oxysporum f. sp. elaeidis may be carried along with the seed and pollen (Flood et al. 1990; Locke and Colhoun 1973). In the Americas, this disease has only been found on two plantations, one in the state of Pará in Brazil (Van der Lande 1985) and the other in Quinindé, Ecuador (Renard and de Franqueville 1989b; Mariau et al. 1992). Due to its broad occurrence in West Africa and very rare presence in America, along with close genetic relationships between the American isolates of F. oxysporum f. sp. elaeidis and those of West Africa, some workers consider that this disease was introduced to Ecuador and Brazil from West Africa (Mouyna 1994) . Up to 1989, Vascular Wilt was reported in the Ivory Coast, Benin, Nigeria, Cameroon, Zaire, Ghana and Congo (Renard and de Franqueville 1989b) besides the two mentioned spots in America.

Blast Disease is another important pathological problem of oil palm in West Africa, affecting the plants mainly during the nursery stage. The causal agent is still unknown, but a vector (Recilia mica: Jessidae) has been identified. The hypothesis of Rhyzoctonia sp. and Phytium sp. as primary causal agents of the disorder is no longer sustained by researchers (Renard and Quillec 1979; de Franqueville et al. 1991). Considering the type of vector, mode of transmission and some characteristics of the disease, it is thought that a Mycoplasma-like organism could be involved (de Franqueville et al. 1991). This disease is not known in the Americas.

Lethal Yellowing, a coconut disease, is caused by a Mycoplasma--like organism and transmitted by Myndus crudus, a leafhopper. In America the disease is found in Florida, along part of the Gulf of Mexico and on some islands in the Caribbean. This disease is not present in any oil palm growing region in the Americas. Also, it has been clearly established in Florida that it is not seed--borne in coconut, and that oil palm is likely to be resistant (Howard and Barrant 1989, Macoy 1983). Confusion between Lethal Bud Rot and Lethal Yellowing may arise from a literal translation of the Portuguese name of the former, called "Amarelecimento Fatal" in Brazil. But Lethal Bud Rot definitively is not related to Lethal Yellowing. A Lethal Yellowing--related disease is present in East and West Africa, where it is called Cape Saint Paul Wilt in Ghana, Kaincope Disease in Togo, Kribi in Cameroon and Awka in Nigeria (Sangare and de Franqueville 1992).

Cadang-Cadang also a coconut disease, is present in part of the Philippines and some nearby islands, but is unknown in the Americas. It is caused by a viroid which can be seed-borne in coconut (Hanold and Randles 1991). Even though, a similar viroid has been detected in oil palm (Hanold and Randles 1989), it has never caused any epidemic in this crop so far.

Other facts and conclusions
The Plant Quarantine authorities in Costa Rica are very strict and conscientious, not only when importing plant material but also when supervising agricultural exports. This small Central American country bases its economy on agriculture. Costa Rica Plant Quarantine regulations are so rigorous that the USA, which is known to be tough in this respect, accepts phytosanitary certificates from Costa Rica at face value.

ASD of Costa Rica is one of the largest oil palm seed suppliers in the international market, a position maintained by more than a decade now. Almost 86 million seeds have been supplied by ASD to hundreds of oil palm growers in 32 countries in three continents, including Asia. During all these years of experience, ASD of Costa Rica has not had any claims of any seed--borne problem.

The Senior Officer Industrial Crops of FAO, an experienced oil palm pathologist, did not observe any diseases transmitted through oil palm seeds originating from ASD de Costa Rica. He has observed no diseases in nurseries or field plantings planted with seed from ASD de Costa Rica in Zambia, Malawi, Uganda, Cameroon, Ethiopia, India, Myanmar or Thailand that could be attributed to seed--borne diseases originating from Costa Rica (Blaak, personal communication 1996).

Giving this excellent record, the strict Costa Rican phytosanitary regulations and the relatively few oil palm diseases in Costa Rica -- none of which are seed borne -- we may safely assert that importing oil palm seeds from Costa Rica poses no risk to any oil palm project in any part of the world.

References

Blair, G. and Darling, D. 1968. Red Ring disease of the coconut palm; inoculation studies and histopathology. Nematologica, 14: 395--403.

________. 1970. Studies on the Red Ring disease of the coconut palm. Oléaginéux, 25 (1): 19--22; 25(2):79--83.

Chinchilla, C. M. 1992. The Red Ring--Little Leaf syndrome in oil palm and coconut. ASD of Costa Rica, Technical Bulletin, 1:1--17.

Chinchilla, C.M.; Oehlschalager, C. and González L.M. 1993. Use of pheromone--based traps for the management of the American Palm Weevil, Rhynchophorus palmarum in a commercial oil palm plantation. In Proceedings, Int. Oil Palm Conf., 20--25 1993. PORIM, Malaysia.

Dollet, M. and López, G. 1978. A study of the association of flagellate protozoa and Marchitez Sorpresiva of oil palm in South America. Oléaginéux, 33(5):209--217.

Flood, J.; Mepsted, R. and Cooper, R. M. 1990. Contamination of oil palm pollen and seeds by Fusarium spp. Mycological Research 94(5):708--709.

de Franqueville, H. and Renard, J. L. 1990. Improvement of oil palm Vascular Wilt tolerance. Results and development of the disease at the R. Michaux plantation. Oléaginéux, 45(10) 399--405.

De Franqueville; Renard, J.L.; Philippe, R. and Mariau, D. 1991. Oil palm Blast: prospect for improvement of the control method. Oléaginéux 46(6): 223--231.

Griffith, R. 1987. Red Ring disease of coconut palm. Plant Disease, 71(2):193--196.

Hanold, D. and Randles, J. W. 1989. Cadang--Cadang--Like viroid in oil palm in the Solomon Islands. Plant Disease 73(2):183.

________. 1991. Coconut Cadang--cadang disease and its viroid agent. Plant Disease 75(4):330--335.

Howard, F. W. and Barrant, C.I. 1989. Questions and answers about Lethal Yellowing Disease. Principles 33(4) 163--171.

Locke, T. and Colhoun, J. 1973. Fusarium oxysporum f. sp. elaeidis as a seed borne pathogen. Trans. Br. Mycol. Soc. 60(3) 594--595.

Manion, P. D. and Lachance, D. (Eds) 1992. Forest Decline Concepts. APS Press. Minnesota. 249 p.

Mariau, D. et al. 1992. Les maladies de type pourriture du couersur le palme á huile in Amérique Latine --Symtomatologie-- Epidímiologie -- Incidence. Oléaginéux 47(11): 605--618.

Mouyna, Isabelle. 1994. Cractérisation moléculaire et étude de la diversité de Fusarium oxsysporum forme spéciale elaeidis responsables de la Fusariose vasculaire du palmier a huile. Thése d'doctorat, Universite Paris VII. 81 pp.

Perthuis, B.; Desmier de Chenon, R. and Merland, E. 1985. Mise en evidence din vecteur de la Marchitez Sorpresiva du palmier á huile, la punaise Lincus lethifer Dolling (Hemiptera: Pentatomidae, Discocephalinae). Oléaginéux, 40(10) 473--475.

Renard J. L. and Quillec, G. 1979. Diseases and abnormalities of the oil palm in the nursery. Oléaginéux, 34(7) 331--337.

_______; and Quillec, G. 1984. Dry Bud Rot of the oil palm. Oléaginéux, 39(10) : 471--476.

_______; and de Franqueville, H. 1989a. Oil Palm Bud Rot. Oléaginéux, 44(2) 87--92.

_______; and de Franqueville, H. 1989b. La fusariose du palmier á huile. Oléaginéux 44(7) : 341--349.

Schuiling, M. and Dinther, J. B. 1981. Red Ring disease in the Paricatuba oil palm estate, Para, Brazil. Zeitschrift for angewandte Entomologie, 91(2) 154--169.

Sangare, A. and de Franqueville, H. 1992. Researches on the coconut Lethal Yellowing disease in Ghana. International Seminar on Coconut Research and Development. Jamaica, October 1992.

Spear Rot of Oil Palm in Tropical America. (1990, Grafische Industrie, Paramaribo). 1988. (Proceedings). Ed. By Ruinard, J.; Nandem Amattaran, T. L. and Tjon A. Joe, H. P. Surinam, Paramaribo.

Van der Lande, H. L. 1985. Vascular Wilt of the oil palm caused by Fusarium oxysporum Schl. At the Paricatuba plantation in Pará, Brazil: the proof of pathogenicity in oil palm seedlings in the prenursery stage. De Surinaamse Landbouw. 33(1) : 1--9.

Vickerman, K. and Dollet, M. 1992. Report on the second Phytomonas workshop, Colombia. Oléaginéux, 47(10) : 593--600.