Classical and fortuitous biological control of the prickly pear cochineal, Dactylopius opuntiae, in Israel

Abstract

The cochineal, Dactylopius opuntiae (Hemiptera: Dactylopiidae) was first reported in Israel in 2013 in a restricted area in the upper Galilee from where, by 2018, it had spread throughout Galilee and the northern Coastal Plain. It infests and kills the Indian-fig prickly pear, Opuntia ficus-indica (Cactaceae), a prominent plant in the landscape of Israel and other Mediterranean countries. Inundative releases of industrially mass-reared Cryptolaemous montrouzieri (Coleoptera: Coccinellidae), intended to control early cochineal outbreaks have been unsuccessful. Two insect predators of D. opuntiae – Hyperaspis trifurcata (Coccinellidae) and Leucopina bellula (Diptera: Chamaemyiidae) – were collected in Mexico and sent to Israel, where both were tested against the target prey and several non-target prey species. Approximately 2500 H. trifurcata individuals were released in the summer of 2017, and 1300 L. bellula individuals in the following summer, mostly at different sites. In midsummer of 2017, a buildup of large populations of naturalized C. montrouzieri was observed in the northern Coastal Plain of Israel where, in 2018, it played a significant role in restraining the cochineal populations. Other local predatory species did not attack the cochineal. Approximately 18 months after release of H. trifurcata, most lightly to moderately infested prickly-pear hedges survived the cochineal attack. Leucopina bellula has been recovered so far at one release site. The establishment in Israel of both predators is a promising solution to the problem, although it is too early to determine how successful this endeavor will be. Further consequences of the acclimatization of the cochineal and its Mexican predators in Israel are discussed including their possible spread into other countries, particularly in Africa where D. opuntiae is being successfully used for biological control of invasive Opuntia species.