Abstract

The insects Calyptocephala marginipennis , Rhynchophorus palmarum and Opsiphanes cassina , and the bird Coragyps atratus have been found to be pests in adult oil palm plantations. In nurseries, the pests found were Spodoptera frugiperda , S. androgea , S. latisfacia and S. sunia. The pollinators are the insects Elaeidobius subvitattus and Mystrops costaricensis .

Introduction

With the aim of evaluating the potential for oil palm ( Elaeis guineensis J.) cultivation in Tabasco, genetic material from the Ivory Coast and Malaysia was introduced in 1969.  In 1970, the plants were sown on 12 hectares in the region of La Chontalpa, in the northwest part of the state.  Then, in 1979, materials were introduced from Costa Rica, which were planted the following year in the region of La Sierra, in the southern part of the state  (Ortiz and Sánchez 1997).

Within the current national oil palm program in Mexico, there are plans to plant more than 2,000 hectares in Tabasco, where some 42,000 hectares have been identified as suitable for the crop (Anonymous 1997).

Due to the above-mentioned plans, it was considered important to carry out a taxonomic survey of the pests and pollinators present in the current oil palm populations in the state.  The results come from observations and collections carried out beginning in 1997 on the previously-mentioned plantations established in 1970 and 1980, as well as on young nurseries present in the state.

Pests

The pests found on adult plantations were the insects Calyptocephala marginipennis (Coleoptera: Chrysomelidae), Rhynchophorus palmarum (Coleoptera: Curculionidae) and Opsiphanes cassina F. (Lepidoptera: Nymphalidae), and the bird Coragyps atratus (Bechstein) (Cathartidae).

C. marginipennis has also been found in Honduras (Hartley 1965), where it is associated with attacks of the fungus Pestalotiopsis sp. (Chinchilla 1997a).  This insect, in both larval and adult stages, damages the back of the folioles by scratching thin grooves a few centimeters long, running parallel to the main nervations.  This damage is observed in both adult and young plants, especially when the last ones grow associated to old plants.

Both R. palmarum and O. cassina are widespread in the American tropics, being two of the main E. guineensis pests in various countries (Genty et al . 1978; Chinchilla 1997b).  Over the course of this study, O cassina pupae were frequently found parasitized by hymenoptera of the Chalcididae family.

The bird, C. atratus , commonly known as the vulture, usually searches out carrion or decayed material.  In oil palm, they have been found feeding on ripe fruit, much of which can be removed from the bunches.  Turner (1970) reports similar damage caused by this bird in Honduras, Costa Rica, and Colombia.

In nursery conditions, various species of defoliating larvae from the Spodoptera genus have been found: S. androgea (Cramer), S. frugiperda (J.E. Smith), S. latifascia (Walker) and S. sunia (Guenée).  Considering the wide distribution of these species in tropical America (Todd and Poole 1980), they are probably also E. guineensis pests in other countries as well. Spodoptera sp.has been found causing damage in Central American nurseries (Obando, 1997).

Pollinators

Although various arthropods have been found to be associated with oil palm inflorescences in Tabasco, at the moment, only Elaeidobius subvitattus Faust (Coleoptera: Curculionidae) and Mystrops costaricensis Gillogly (Coleoptera: Nitidulidae) are reported to be pollinators.  These two insects were the main oil palm pollinators in tropical America before the introduction of the species E. kamerunicus from Africa.  In Mexico, they had been found in Chiapas (Genty et al . 1986).  The present report identifies the La Chontalpa oil palm plantation, located between 17 59 north latitude and 93 38 west longitude, as the northernmost point for both species to be found.

Due to the low population of M. costaricensis encountered, it was not possible to determine the subspecies present in Tabasco.  However, it is probably costaricensis , as the other two subspecies are found only in South America (Genty et al . 1986).

During the dry season in which collections were made, E. subvitattus populations were plentiful.  However, it is necessary to study the population dynamics of both species in order to understand their importance in the pollination and production of oil palm in Tabasco.  Ants (hymenoptera: Formicidae) of an unidentified species were seen carrying off S. subvitattus larvae, which means they could be considered a natural enemy of this pollinator.

Acknowledgements

To Dr. Carlos Chinchilla of ASD Costa Rica for his confirmation of the species Calyptocephala marginipennis .

References

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