Predatory potential and feeding preference of Cryptolaemus montrouzieri on Dactylopius opuntiae under laboratory conditions
Recently the introduced mealybug, Dactylopius opuntiae, has been the most devastating insect of cactus in Morocco. The cochineal has spread to many regions of the kingdom and caused enormous socio-economic and environmental losses. To control this menace, predatory potential of Cryptolaemus montrouzieri was investigated under laboratory conditions at 26±2°C, 60±10% RH and 12:12 h L:D regime. In this study, the experiments were conducted in choice feeding tests (D. opuntiae second instar, first instar nymphs and eggs were offered simultaneously). C. montrouzieri adults and fourth instar larvae were the most feeders’ predators on different stages of D. opuntiae. Manly’s preference index values showed that all predator stages preferred younger stages of mealybug (p < 0.5), (negative switching). Furthermore, studies on development time showed that egg, larvae, prepupal, pupal and adult stages duration were 3.60±0.67, 4.05±0.90, 4.45±0.85, 5.48±0.91, 8.15±0.36, 1.48±0.60, 10.80±0.65, and 103.28±2.37, respectively. The results of this study showed that C. montrouzieri has the ability to be exploited as a predator of D. opuntiae in Morocco.
Keywords: Dactylopius opuntiae, Cryptolaemus montrouzieri, Opuntia ficus-indica, biological control, Morocco