Towards Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae) biological and integrated management at field conditions in Cadiz province (Spain)

Abstract

The false carmine cochineal Dactylopius opuntiae has been originally used as biological control agent of the prickly pear cactus Opuntia ficus-indica Miller, considered as an exotic invasive species in many countries including Spain. However, the extremely high level of infestation has resulted in great inconvenience to the population of local residents and a serious threat to wipe out a plant that is already part of the Andalusian landscape. In the present research, different control means were evaluated towards this cochineal at field condition in a site in the province of Cadiz (Spain). The populations of the insect in the study site were confirmed to belong to D. opuntiae. We detected this insect throughout the study area with a very high population density in terms of number of colonies per cladode and the extent of the infestation. We also evaluated the efficacy of four different methods (Chlorpyrifos-methyl, Potassium soap, Cryptolaemus montrouzieri larvae, the entomopathogenic fungus Beauveria bassiana) for the control of D. opuntiae. Our results demonstrated that the Potassium soap and Chlorpyrifos-methyl were the best treatments in reducing D. opuntiae populations, with relative population density values being negative only in these two treatments, and efficacies of 91.5 and 76.7% respectively. The results of this investigation showed that the current situation of false carmine cochineal is worrisome, but nevertheless, the use of Potassium soap for its control is recommended because of its high efficacy and low environmental impact.