Abstract

A report dating from 1986 indicates that the Asian rhinocerous beetle Oryctes rhinoceros L . was found associated with coconut palms in the State of Tabasco. However, more recent observations showed that the species in question could quite possibly have been Strategus aloeus L .

Introduction

Various species of coleopterans of the Scarabeidae family, commonly referred to as rhinocerous beetles, are important pests in many palms, including the oil and the coconut palms. The genus Oryctes is found in the old world, while Stategus is found in the Americas (Bachy 1963, Child 1964, Piggott 1964, Lever 1969).

O. rhinoceros is found to be widespread is Southeast Asia and the Pacific Islands (Lever 1969, Hill 1975). The damage is caused by the adults, which feed on the center of the plant's crown, including new leaves which have yet to open. When these leaves open, they show a characteristic deformity in the form of V--shaped cuts. In coconut palms, the spathes and inflorescences are also commonly attacked. The plants may die either as a result of direct destruction of the growth points or of infections caused by opportunist pathogens. Sometimes the damage is aggravated due to the attraction of other coleopterans from the genus Rhynchophorus to the already--damaged areas (Menón and Pandalai 1958, Hartley 1967, Wood 1976, Taffin 1993).

According to External Quarantine number 16, currently in effect in Mexico, O. rhinoceros is not present in the country. However, Salcedo (1986) refers to its presence on the Tabasco coast, in association with young coconut palms.  Due to the importance of this pest in Asia, it was considered of utmost importance to either confirm its presence in Mexico or invalidate the above--mentioned report.

Methodology

Information was gathered on the morphology of Oryctes rhinoceros adults and the type of damage caused (Menón and Pandalai 1958, Child 1964, Piggott 1964, Lever 1969, Taffin 1993) in order to study and compare the species of the Scarabaeidae family housed in the entomological collection at the Postgraduate School, Tabasco campus.  Subsequently, field trips were made to coconut palm plantations in order to search for evidence of damage caused by O. rhinoceros and to collect beetles associated with the crop.  This project was carried out between October, 1996 and August, 1997.

Results and discussion

S. aloeus is found in widespread distribution in the Americas, and is a common pest in coconut and oil palms (Bondar 1940, Hartley 1967, Mariau 1976, Genty et al . 1978, Chinchilla 1997).  It is found in almost all the states of Mexico (Morón et al . 1997), and has been classified as a species detrimental to the coconut palm (García 1981).

Besides Salcedo's (1986) report on the presence of O. rhinoceros in Tabasco, there is no indication of its presence in Mexico. However, various observations point to the incorrect identification of Strategus aloeus as O rhinoceros .

Although O. rhinoceros and S. aloeus are generally similar in appearance, there are notable morphological differences between them.  One of these is the position of the ceratoid projection or horn on the front part of the body.  In O. rhinoceros , it appears on the head, while in S. aloeus it is seen on the forward edge of the pronotum (Menón and Pandalai 1958). The males of the species S. aloeus also display two other horn--like projections on the sides of the pronotum, which do not appear in O. rhinoceros .

Salcedo (1986) notes that O. rhinoceros attacks young coconut palm plants (under three years old).  However, this species is actually capable of attacking plants of any age (Piggott 1967, Lever 1969, Hill 1975).   Strategus aloeus normally restricts its activity to young palms, especially those in their first two years in the field (Hartley 1967, Lever 1969, Mariau 1976, Genty et al . 1978).

The feeding patterns of O. rhinoceros and S. aloeus show notable variation. The first species establishes itself in the bud of the plant and then works its way down to the terminal shoot.  The adult S. aloeus digs into the base of the plant and then works its way up (Child 1964, Piggott 1964, Fremond et al . 1966, Hartley 1967, Lever 1969, Genty et al . 1978).

Conclusions

The presence of the Asiatic Rhinocerous Beetle Oryctes rhinoceros could not be confirmed in Tabasco.  However, the species Strategus aloeus was found in association with coconut palms, and it is very possible that this species had been incorrectly identified as O. rhinoceros in the past.

In Tabasco and other Mexican states, plans are currently being carried out to introduce oil palm cultivation, with S. aloeus expected to be part of the fauna detrimental to the new crop.

References

Bachy, A.1963.  Insectes et animaux nuisables au palmier a huile.  Oléagineux 18(1): 15--18.

Bedford, G.O. 1977.  Informe sobre al visita a México del 7 de diciembre de 1976 al 25 de enero de 1977.  Escuela de Ciencias Biológicas. Facultad Tecnológica de Sydney. Australia. 25 p.

Bondar, G. 1940.  Insectos nocivos e molestias do coqueiro  ( Cocos nucifera ) no Brasil.  Tipografía Naval.  Bahía, Brasil. 160 p.

Child, R. 1964.  Coconuts.  Tropical Agriculture Series. Longmans.  London. 216 p.

Chinchilla, C.M.  1997.  Fauna perjudicial en palma aceitera.   In :  Memorias del Curso Aspectos Generales del Cultivo de la palma Aceitera.  ASD de Costa Rica.  49 p.

Fremond, Y., R. Ziller et M.N. de Lamothe.  1996.  Le cocotier. Techniques Agricoles et Productions Tropicales. VIII. G.--P.  Maisonnueve & Larose.  Paris.  267 p.

García M., C. 1981.  Lista de insectos y ácaros perjudiciales a los cultivos en México.  Fitófilo 86:7--196.

Genty, P.M R.D. de Chenon et J.P. Morin. 1978.  Les ravageus du palmier a huile en Amérique Latine.  Oléagineux 33 (7) : 324--420.

Hartley, C.W.S. 1967.  The oil palm ( Elaeis guineensis Jacq.).  Longmans. London. 706 p.

Hill, D.S. 1975. Agricultural insect pest of the tropics and their control.  Cambridge University Press.  Cambridge. 516 p.

Lever, R.J.A.W. 1969.  Pests of the coconut palm.  FAO.  Rome. 190 p.

Mariau, D. 1976.  Insect pest in South America.  In:  Oil Palm Research. Developments in Crop Science (1). Corley, R.H.V., J.J. Hardon and B.J. Wood  (eds.).  Elsevier Scientific Publishing Company.  Amsterdam.  pp. 387--393.

Menon, K.P.V. and K.M. Pandalai. 1958.  The coconut palm a monograph.  Indian Central Cococut Committee. Pyarelal Sah at the Times of India Press.  Bombay. 384 p.

Morón, M.A., B.C. Ratcliffe y C. Deloya.  1997.  Atlas de los escarabajos de México.  Coleoptera:  Lamellicornia.  Vol. I Familia Melolonthidae.  Subfamilias Rutelinae, Dynastinae, Cetoniinae, Trichiinae, Valgine y Melolonthinae. Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, y Sociedad Mexicana de Entomología.  México. 280 p.

Pigott, C.J. 1964.  Coconut growing.  Oxford University Press. London. 109 p.

Salcedo G., J.G. 1986.  La producción coprera en el estado de Tabasco. Colección Cuadernos Universitarios.  Serie Agronomía No. 11.  Universidad Autónoma Chapingo. México. 186 p.

Taffin, G. de. 1993. Le cocotier.  Le Technicien d' Agrilculture Tropicale. 25 Maisonneuve & Larose.  Paris.  166 p.

Wood, B.J. 1976.  Insect pest in south east Asia.  In:  Oil Palm Research. Developments in Crop Science (1).  Corley, R.H.V., J.J. Hardon and B.J. Wood (eds.).  Elsevier Scientific Publishing Company.  Amsterdam. pp. 347-367.