Florida Entomologist (2002) 85, 409-416

R.J. Stuart, J.P. Michaud, L. Olsen and C.W. McCoy (2002)
Lady beetles as potential predators of the root weevil Diaprepes abbreviatus (Coleoptera: Curculionidae) in Florida citrus
Florida Entomologist 85 (3), 409-416
Abstract: Diaprepes abbreviatus (L.) is a major pest of Florida citrus. Adult females lay eggs in masses sealed between leaves in the citrus canopy, and recently-hatched neonate larvae drop to the soil and feed on roots. The coccinellid species, Cycloneda sanguinea (L.), Harmonia axyridis Pallas, and Olla v-nigrum Mulsant, are generalist predators that consume a wide range of citrus pests, although they have not been observed preying on Diaprepes. We conducted experiments to determine whether these species would feed on Diaprepes egg masses and neonate larvae, and how an exclusive or partial diet of Diaprepes eggs would influence their development. The three predators responded very similarly in our tests. In laboratory assays, coccinellid larvae and adults readily consumed exposed Diaprepes eggs and neonates less than 48 h old; and coccinellid larvae preyed on 40% of intact egg masses laid between wax paper strips or citrus leaves, whereas adults preyed on 8.7%. In a greenhouse assay, coccinellid larvae located and preyed on 22.7% of intact egg masses laid between leaves on potted citrus trees. Although neonates might have relatively limited exposure to predation in the canopy before they drop to the soil, predation could be an important factor selecting for the timing of egg hatch, neonate escape from leaf envelopes, and neonate drop. The develop-mental assays indicate that Diaprepes eggs are less suitable prey for these coccinellid species than eggs of the flour moth, Ephestia kuhniella Zeller, but that they could be a highly acceptable component of a mixed diet. Our experiments indicate that these coccinellid species are potentially important predators of Diaprepes but the extent to which they contribute to the natural biological control of this weevil remains unknown.

El picudo de los cítricos, Diaprepes abbreviatus (L.) es una plaga séria de cítricos en Florida. Hembras adultas ponen huevecillos en masas selladas dentro hojas en la copa del arbol, y las larvas neonatas recien-eclosionadas caen al suelo y comen de los raices. Las catarinitas Cycloneda sanquinea (L.), Harmonia axyridis Pallas, and Olla v-nigrum Mulsant son depredadores generalistas que consumen un rango amplio de insectos dañinos en citricultura, aunque no han sido observados consumiendo Diaprepes. Experimentos fueron llevado a cabo para determinar si estas espécies consumiera huevos y neonatos de Diaprepes, y como dietas de huevecillos y neonatos, exclusivas o parciales, influiera su desarollo larval. Los tres depredadores respondieron en forma parecida en nuestros experimentos. In pruebas de laboratório, larvas y adultos consumieron en seguida huevecillos de Diaprepes expuestos y neonatos menos que 48 h de edad. Larvas atacaron 40% de masas de huevecillos sellado den-tro hojas de papel encerado, o hojas de citrus, mientras que adultos atacaron 8.7%. Enuna prueba de invernadero, larvas de Coccinellidae atacaron 22.7% de masas de huevecillos en arboles de cítricos en tiestos. Aunque los neonatos no son exquesto a la depredacion por largo plazo en el arbol antes de caer al suelo, la depredacion puede ser un factor importante en la evolución del tiempo de eclosión de huevecillos, salida de neonatos del sobre de hojas, y caida de neonatos al suelo. Las pruebas de desarollo mostraron que los huevecillos de Diaprepes son presas menos apropiadas para larvas de estas espécies que huevecillos del pomilla de harina, Ephestia kuhniella Zeller, pero indican que huevecillos de Diaprepes podian ser una presa altamente acceptable dentro una dieta mesclada. Sobre todo, nuestros experimentos indican que éstas espécies de Coccinellidae son depredadores de Diaprepes potencialmente importante, pero el alcance de tal depredacion en la naturaleza queda desconocido.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Full text of article
Database assignments for author(s): Robin J. Stuart, J.P. Michaud

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SE)
Harmonia axyridis (predator)	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SW)
Cycloneda sanguinea (predator)	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SW)
Olla v-nigrum (predator)	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SW)