Chilocorus cacti (Coleoptera: Coccinellidae) as a Biological Control Agent of the Wild Cochineal (Hemiptera: Dactylopiidae) of Prickly Pear Cactus.

The wild cochineal (Dactylopius opuntiae Cockerell) (Hemiptera: Dactylopiidae) is considered to be the most important pest in cactus pear plantations. In Mexico, there are seven natural enemies that provide natural biological control of D. opuntiae. However, their role and impact have not been evaluated. In this article, we report on aspects of the population biology of Chilocorus cacti L. (Coleoptera: Coccinellidae), which is considered one of the main natural enemies of D. opuntiae. We also conducted experiments to evaluate the consumption of C. cacti by this predator when fed nymphs and adult females of D. opuntiae. Changes in the survival function of D. opuntiae in the presence or absence C. cacti were also identified. Both larvae and adults of C. cacti prefer to consume D. opuntiae nymphs because the wax produced by adult females presents a significant obstacle. The survival analysis showed that the presence of C. cacti had significant negative effects on D. opuntiae survival. C. cacti significantly increased its abundance while reducing the density of adult female D. opuntiae, but this impact occurred only after they had consumed the more preferred nymphs. For this reason, natural enemies other than C. cacti may be required to achieve adequate levels of biological control.