Control Methods
In Hawaii, biological control solved the problems linked with the heavy infestations of C. angraeci: soon after its discovery in 1989, the Aphelinidae Marietta pulchella exerted a complete control on the scale, which is now considered to be rare (Beardsley, 1993).
Very few data are available on the results of chemical control trials against this scale. Experiments conducted in 2004 by the Plant Protection Service of Reunion Island showed a high effectiveness of imidacloprid (C.P.: Confidor; Bayer CropScience) and a good effectiveness, though delayed and inferior to that of imidacloprid, is of mineral oil (C.P.: Ovipron; Cerexagri) (SPV Réunion, 2004). Further experiments using mineral oils are required, with applications at different periods of the year, to determine its effectiveness in controlling the scale. As mobile instars are more sensitive to chemical control, such treatments, if not phytotoxic, should preferentially be applied during summer when the first instar is more abundant and active.
The vanilla scale has demonstrated, at least in certain areas, its ability to cause significant damage to vanilla production. Despite a few studies devoted to this scale, our knowledge is limited about the bio-ecology of this pest. Additional studies would be helpful to improve our knowledge on its natural enemies and their impact, as well as on possible control methods.
Acknowledgments
The authors express their sincere thanks to the taxonomists who identified the para-sitoids (G. Delvare, CIRAD, Montpellier, France), the predatory mites (E.A. Ueckermann, PPRI, Pretoria, South Africa), and the thrips (B. Michel, CIRAD, Montpellier, France).
References
Alabouvette, C. and M. Grisoni. 2009. Mission d’expertise en phytopathologie du vanillier dans la SAVA. Rapport provisoire CTHT/FED-Stabex, Toamasina (Madagascar), 35pp. (+ Annexes).
Beardsley, J.W. 1993. Exotic terrestrial arthropods in the Hawaiian islands: Origins and impacts. Micronesica Suppl. 4:11–15.
Beardsley, J.W. and D.M. Tsuda. 1990. Marietta pulchella (Howard) (Hymenoptera: Aphelinidae), a primary parasite of Conchaspis angraeci Cockerell (Homoptera: Conchaspididae). Proc. Hawaiian Entomol. Soc. 30:151–153.
Ben Dov, Y. 1974. On the species of Conchaspididae (Homoptera: Coccoidea) from Africa and Madagascar with description of a new species. Rev. Zool. Afr. 88 (2):363–373.
Ben Dov, Y. 1981. A catalogue of the Conchaspididae (Insecta: Homoptera: Coccoïdea) of the world. Annales Soc. Entomol. France 17 (2):143–156.
Ben Dov, Y., Y. Shanuni, M. Mizrahi, M. Weiss, Y. Feldman, and M. Feldmann. 1985. Interceptions of scale insects (Coccoïdea) at port of entry in Israël. Hassadeh 85:2120– 2121, 2128.
Cockerell, T.D.A. 1893. Coccoïdea or scale insects. II. Bull. Bot. Dept. Jamaica 40: 9.
Goff, M.L. and P. Conant. 1985. Mites feeding on scale insects. Proc. Hawaiian Entomol. Soc. 25:4.
Grisoni, M. 2007. Rapport de mission à l’île Maurice pour la Compagnie d’Exploitation de Vanille Naturelle Limitée (CEVNL), du 5 au 6 mai 2008. Doc. CIRAD, 16pp.
Grisoni, M. and A.L. Abdoul-Karime. 2007. Epidémiosurveillance de Mayotte et des Comores. Rapport technique. Décembre 2007. Doc. CIRAD - Délégation de Mayotte, 34pp.
Hamon, A.B. 1979. Angraecum scale, Conchaspis angraeci Cockerell (Homoptera: Coccoidea: Conchaspididae). Entomology Circular, Division of Plant Industry, Florida Department of Agriculture and Consumer Service, 2pp.
Mamet, R. 1954. A monograph of the Conchaspididae Green (Hemiptera: Coccoidea). Transactions of the Royal Entomological Society of London 105:189–239.
Quilici, S. 2002. Rapport de mission en Polynésie du 29/10 au 12/11/2002. Doc. CIRAD Réunion/3P, 24pp.
Richard, A., C. Rivière, P. Ryckewaert, B. Come, and S. Quilici. 2003. Un nouveau ravageur de la vanille, la cochenille Conchaspis angraeci. Etude préliminaire à la mise en place d’une stratégie de lutte raisonnée à La Réunion. Phytoma – La Défense des Végétaux 562:36–39.
Richard, A. 2003. Rapport de mission à Mayotte du 14 au 18/03/2003. Doc. CIRAD Réunion/3P, 9pp.
SPV Réunion. 2004. Expérimentation sur la cochenille de la vanille. Conchaspis angraeci Cockerell. Ministère de l’Agriculture et de la Pêche, Direction de l’Agriculture et de la Forêt de La Réunion, 11pp.
Takagi, S. 1992. A contribution to Conchaspidid systematics (Homoptera: Coccoidea). Insecta Matsumurana 46:1–71.
Takagi, S. 1997. Further material of Conchaspis from Southeast Asia (Homoptera: Coccoidea: Conchaspididae). Insecta Matsumurana 53:27–79.
Williams, D.J. and G.W. Watson. 1990. The scale insects of the tropical south Pacific region. Part 3. The soft scales (Coccidae) and other families. CAB International Institute of Entomology Ed, 205–207.
Chapter 10. Anatomy and Biochemistry of Vanilla Bean Development (Vanilla planifolia G. Jackson)
Fabienne Lapeyre-Montes, Geneviève Conéjéro, Jean-Luc Verdeil, and Eric Odoux
Introduction
The fruit of the vanilla plant is commonly known as a “bean” being similar in shape with those of legumes, which stems from the evolution of a single carpel. In fact, from a botanical viewpoint, it is not actually a bean as it results from the evolution of three fused carpels, but a capsule (dry, dehiscent fruit resulting from the evolution of several carpels). In the orchid family, which includes the genus Vanilla, the capsule is composed of three valves that are delimited by six dehiscence splits (two per carpel) situated at either end of the placentas (paraplacental dehiscence, Figure 10.1a) (Dupont and Guignard, 2007).
FIGURE 10.1 Paraplacental dehiscence: (a) general case of an orchid family capsule (six dehiscence splits resulting in three valves); (b) specific case of a V. planifolia capsule (two dehiscence splits resulting in two valves).