Efficiency of Ladybeetles (Coccinellidae: Coleoptera) in Insect Control

A most remarkably effective control and often total elimination of some scale insects and exposed mealybugs by ladybeetles—Coccinellidae: Coleoptera—occurred on the tropical Island of Puerto Rico, affecting such introduced plants as coconut palm, grapefruit, bamboo, and Australian pine. No comparable control resulted of aphids, either by introduced ladybeetles or endemic species, presumably in ecologically balanced adjustment to their environment. Indeed, the native ladybeetles became scarce, or tended to disappear. None feeds on Myzus persicae, a major pest of eggplant and pepper, and most recently on tobacco. No instance of effective control of the yellow aphid of sugarcane, Sipha flava, due to ladybeetles, has been observed.