An explanation for outbreaks of Coelaenomenodera lameensis Berti & Mariau (Coleoptera: Chrysomelidae), a leaf miner of oil palm (Elaeis guineensis Jacq.) in West Africa, based on a study of mortality factors

Abstract

The leaf miner Coelaenomenodera lameensis Berti & Mariau (Coleoptera: Chrysomelidae: Hispinae) is the most serious pest of oil palm in West Africa. A study of mortality factors was carried out at 19 sites located in seven plantations of 3000 -7000 ha, over a 2 -4-year period in the early 1980s throughout the forest zone of Cô te d'Ivoire, West Africa. All life history stages of C. lameensis were found to be attacked by natural enemies. Fluctuations in numbers of egg parasitoids were related to climatic factors and host population dynamics and parasitism rates varied substantially among sites. High egg mortality in C. lameensis, related to parasitism, was directly linked to climatic factors, mainly relative humidity. Fluctuations in egg mortality not linked to parasitism were similar among plantations. There was also a negative correlation between beetle fecundity and egg mortality; climatic conditions favourable to an increase in fecundity also disfavoured egg mortality. This can be a major cause of population increase of larval C. lameensis. Different species of larval and pupal parasitoids and predators were observed. In addition, viruses, isolated from dead larvae in galleries, killed 55 -60% of the larvae, probably playing an important role in limiting populations. The destruction of mines by several species of ants also eliminated about 25% of beetle larvae. Parasitoids played a smaller role (less than 10% of larval mortality is due to parasitoids). Mortality in larvae and pupae can exceed 90%, but varied widely from one plantation to another. Examples of mortality tables are given for clearly characterized situations and they help to explain the stability of populations and the occurrence of outbreaks on a plantation or sites scale. Mortality rates lower than 98.6% can lead to population instability and an outbreak in an area.

Natural history of Javeta pallida Baly, 1858 on Phoenix palms in India (Chrysomelidae, Cassidinae, Coelaenomenoderini)

“…In Coelaenomenodera (Coelaenomenodera) lameensis eggs are laid in clusters inside cavities dugout on the leaf lamina and covered with faeces (Berti and Mariau 1999). We did not find groups of eggs, as has been noted for other Coelaenomenoderini — Coelaenomenodera (Coelaenomenodera) elaeidis (Cachan 1957; Morin and Mariau 1970, 1971, 1974; Mariau and Morin 1972, 1974) and Coelaenomenodera (Coelaenomenodera) lameensis (Berti and Mariau 1999; Mariau and Lecoustre 2000, 2004). In Javeta pallida , the slits in which eggs are laid, are independent of the adult feeding scars.…”

“…This has been described for Coelaenomenodera (Coelaenomenodera) elaeidis (Mariau and Morin 1972; Bernon and Graves 1979) and Coelaenomenodera (Coelaenomenodera) lameensis (Mariau and Lecoustre 2004). There are many such sporadic pests, such as the rice caseworm, Nymphula depunctalis (Guenee) (Lepidoptera: Pyralidae), rice swarming caterpillar, Spodoptera mauritia (Boisduval) (Lepidoptera: Noctuidae), and locusts having periodic swarms and outbreaks.…”

“…Hymenoptera parasitoids belonging to the families Eulophidae and Trichogrammatidae act as the most important natural enemies of Coelaenomenoderini (Waterston 1925; Kerrich 1970, 1974; Boucek 1976; Viggiani 1980; Cox 1994; Mariau and Lecoustre 2004; Aneni 2014a, b). Morin and Mariau (1971) studied parasites and predators of the egg while Mariau et al (1978) uncovered the parasites in each of the four larval instars.…”

“…Due to the mining behavior, palm leaflets are severely damaged and produce lower yields (Ruer 1964) by as much as a 30% reduction (Simmonds 1970). The biology, life cycle and enemy complex are well-documented for Coelaenomenodera (Coelaenomenodera) elaeidis (see Maulik 1920; Cotterell 1925; Waterston 1925; Cachan 1957; Morin and Mariau 1970, 1971, 1974; Mariau and Morin 1971, 1972, 1974; Mariau 1976, 1999; Mariau et al 1978; Bernon and Graves 1979; Philippe et al 1979; Mariau and Philippe 1983; Philippe 1990; Timti 1991; Mariau et al 1999a), Coelaenomenodera (Coelaenomenodera) lameensis Berti and Mariau (see Berti and Mariau 1999; Mariau and Lecoustre 2000, 2004; Mariau 2001), Coelaenomenodera (Coelaenomenodera) perrieri Fairmaire (Mariau 1988, 2001; Lecoustre et al 1980), and Coelaenomenodera (Coelaenomenodera) speciosa Gestro (Uhmann 1961; Santiago-Blay 2004). These provide a model for research on other coelaenomenoderine species which might pose pests of economically-valuable palms.…”

Évaluation de la sensibilité de sept clones de palmier à huile (<i>Elaeis guineensis</i> Jacq.) à <i>Coelaenomenodera lameensis</i> Berti et Mariau (Coleoptera, Chrysomelidae) Konan J.

“…En effet, les dégâts occasionnés par ce coléoptère peuvent provoquer, selon Lecoustre (1988), une baisse de production chez le palmier à huile pouvant atteindre 30 à 50 % sur une période de deux à trois ans. Si certains travaux ont confirmé des méthodes de luttes chimiques et biologiques contre cet insecte (Philippe, 1990 ;Mariau, 2001 ;Mariau et Lecoustre, 2004 ;Coffi et al, 2012 ;Tanoh et al, 2013 ;Aneni et al, 2014 ), la lutte génétique, à travers la sélection et la vulgarisation de matériel résistant à C. lameensis, fait encore l'objet de recherches actives (Raymonda et al, 2011). Coffi et al (2012), à travers la comparaison de la sensibilité de différents stades larvaires de la mineuse des feuilles à des extraits de polyphénols totaux de cinq matériels (E. oleifera, Deli, La Mé et 2 backcross), ont montré que le comportement des larves de C. lameensis variait en fonction des matériels testés.…”