Inundative release of coccinellid beetles into eucalypt plantations for biological control of chrysomelid leaf beetles

Abstract

1 Inundative augmentative releases of adult coccinellid beetles were assessed for their potential to effectively supplement biological control of outbreak populations of the Eucalyptus leaf beetle Chrysophtharta bimaculata in Eucalyptus nitens plantations. 2 Mixed groups of two species of overwintering coccinellids, Cleobora mellyi and Harmonia conformis, were collected from the field then fed three diets in the laboratory prior to release. Both species were released in the summer into two E. nitens plantations with economically damaging Chrysophtharta populations. 3 Differences between dispersal of coccinellids fed the three diets were slight; beetles brought straight out of overwintering before release were initially slower moving onto trees. 4 Numbers of coccinellids on trees in monitoring plots decreased exponentially with time, and populations had returned to prerelease levels 7 days after release. The number of coccinellids recaptured decreased with increasing distance from the release point with very few coccinellids per tree at 70 m distance. Dispersal of C. mellyi away from the release plot was slower than that of H. conformis. 5 Numbers of coccinellids on trees were significantly related to predation levels of C. bimaculata with a large decrease in the C. bimaculata population to below the economic damage threshold in plots where the numbers of coccinellids were high. 6 The results of this study suggest that inundative release of laboratory reared coccinellids is possible for biological control of C. bimaculata, although it may only be economically viable in small, environmentally sensitive areas.

Cityscape quality and resource manipulation affect natural enemy biodiversity in and fidelity to urban agroecosystems

“…For the release, we marked ladybeetles with yellow fluorescent insect marking powder (BioQuip item #1162Y) to identify upon recapture (Online Resource 1). The use of fluorescent powders is a common method in markrecapture studies to assess dispersal of ladybeetles (Baker et al 2003), parasitoids (Corbett and Rosenheim 1996), and other insects (Kareiva 1985) because it does not significantly affect survival or flight (Naranjo 1990) and thus recapture. We released 35,000 marked individuals (1/2 US gallon, recommended amount for small farms and large gardens by these companies (see e.g., www.arbicoorganics.com) in each of the 12 gardens during cool (\ 16°C) and overcast weather conditions so that ladybeetles could acclimate to and experience the garden.…”

Coccinellids in Biological Control

“…Thus many demonstration projects have shown potential effi cacy, but have failed to evolve into tactics that are attractive or economically viable pest control alternatives. For example, Baker et al (2003) successfully released overwintered adults of Cleobora mellyi and Har. conformis against the leaf beetle Chrysophtharta bimaculata on eucalyptus trees in Australia, but concluded this approach was only economically feasible in small, environmentally sensitive areas where pesticide use was not acceptable.…”

Leptotrachelus dorsalis(Coleoptera: Carabidae): A Candidate Biological Control Agent of the Sugarcane Borer in Louisiana

“…The weekly sample size was 400 stalks. ed success in controlling chrysomelid leaf beetles in Eucalyptus (Baker et al 2003). However, those authors report that the approach may only be economically viable in small, environmentally sensitive areas.…”