Sources de résistance d'Opuntia spp. contre la cochenille à carmin, Dactylopius opuntiae, au Maroc

Abstract

La pr esente etude analyse la r esistance de diff erentes esp eces de cactus d'Opuntia spp. a Dactylopius opuntiae (Hemiptera: Dactylopiidae) sur la base de 248 ecotypes d'Opuntia spp. issus de la collection de l'Institut National de la Recherche Agronomique (INRA) du Maroc. L'identification d' ecotypes r esistants a cette cochenille pourra servir a la reconstitution des vergers d'Opuntia spp. qui ont et e totalement ravag es dans plusieurs r egions du royaume du Maroc. Les infestations naturelles et artificielles a partir des haies avoisinantes ont et e suivies sur une parcelle d'un hectare contenant 744 plants de cactus appartenant a ces 248 ecotypes d'Opuntia spp. (bloc al eatoire complet avec trois r ep etitions). Les donn ees relatives a l' etat v eg etatif des plants de cactus, et a leur degr e d'infestation par la cochenille ont et e relev ees r eguli erement. Les r esultats ont montr e que seuls sept ecotypes (Marjana, Belara, Karama, Ghalia, Angad, Cherratia et Melk Zhar) ont pr esent e une r esistance totale a la cochenille, alors que 241 ecotypes ont et e infest es au cours de l' etude. Les sept ecotypes d'Opuntia spp. r esistants a D. opuntiae ont et e inscrits au catalogue national du cactus et une parcelle de pieds m ere a et e plant ee avec ce mat eriel v eg etal. Ces ecotypes r esistants feront l'objet ult erieurement d'une etude du m echanisme de r esistance (antibiose ou antixenose) pour la cochenille ainsi que de travaux de recherche pour l'am elioration g en etique du cactus au Maroc.

Chemical Composition and Insecticidal Potential of Six Essential Oils from Morocco against Dactylopius opuntiae (Cockerell) under Field and Laboratory Conditions

“…Nymphs and adult females of D. opuntiae feed directly on plants by sucking sap on the cladode, causing drying, weakening, and eventually death of the plant host [4]. Several promising integrated pest management options (host plant resistance, biological control, and biopesticides) for the control of the cochineal are being developed in Morocco [5][6][7][8][9].…”

Life history of Dactylopius opuntiae (Hemiptera: Dactylopiidae) on Moroccan resistant cactus germplasm

“…Indeed, the first two axes have allowed enrichment of scientific knowledge useful for the continuation of the work related to the control of this new pest, while the third axis on the varietal resistance of cactus to the mealybug, was the relevant and saving solution. Thus, initially, the ten genotypes identified resistant by research in Morocco, will constitute a solid foundation for the launch of the national program of recovery of cactus decimated across the country by the Ministry of Agriculture, Maritime Fishing, Rural Development, and Water and Forests [23]. Our study documents the first study on the life history of D.opuntiae on the ten genotypes identified as resistant in Morocco using antexenosis and antibiosis tests in the laboratory and greenhouse.…”

“…The ten cactus genotypes tested in this study were brought collected from an INRA (National Institute for Agricultural Research) national cactus collection. Eight of these resistant genotypes (Karama, Ghalia, Belara, Marjana, Melk Zhar, Cherratia, Angad, and Aakria) have been identified as resistant to D. opuntiae and are already registered in the Catalogue Officiel of Cactus in Morocco [23] (Table 1).…”

“…This plan also included a research program covering the most important management elements such as host plant resistance [23], pesticides, beneficial insects [24,25,26,27,28], and biopesticides [29]. Of all the investigated research pathways, the identification of ten mealybug-resistant genotypes is the part that offers great hope for the revival of the cactus industry at the present time [23]. Resistant genotypes are showing positive results in Brazil as well.…”

“…Considering the urgency of the mealybug, and to avoid the spread of this epidemic, the Ministry of Agriculture, Maritime Fishing, Rural Development, and Water and Forests-Morocco, put in place a major emergency plan for the control of this mealybug in 2016. This plan also included a research program covering the most important management elements such as host plant resistance [23], pesticides, beneficial insects [24,25,26,27,28], and biopesticides [29]. Of all the investigated research pathways, the identification of ten mealybug-resistant genotypes is the part that offers great hope for the revival of the cactus industry at the present time [23].…”