Risk assessment of non-target effects of Closterocerus chamaeleon (Girault) parasitoid of the eucalypt gall maker Ophelimus maskelli (Ashmead) (Hymenoptera, Eulophidae)

Abstract

The pre-release risk assessment, a recommended practice in biological control programmes, was carried out before introducing Closterocerus chamaeleon (Girault), a eulophid parasitoid of the eucalypt gall maker Ophelimus maskelli (Ashmead) (Hymenoptera, Eulophidae), in Sicily, Italy. We evaluated its host specificity in laboratory small arena no-choice tests on six non-target hosts, using O. maskelli as a control species. The non-target species fit with at least one of the following criteria: a) common geographical origin; b) ecological or behavioural affinities with the target host; c) concealed habit of the preimaginal stages; d) taxonomic affinity; e) taxonomic affinity with hosts of congeneric parasitoids of the candidate agent; and f) presence in Italy/Sicily. Closterocerus chamaeleon performed an oviposition sequence of 10 recognisable behaviours, always leading to parasitization when exposed to O. maskelli. The same behaviour sequence was carried out on the gall maker Leptocybe invasa Fisher et La Salle, the only non-target species living on Eucalyptus, but just until Step 6, i.e. until ovipositor extraction and insertion, and never until egg-laying. All of the other non-target hosts were ignored. Furthermore, the adult parasitoid longevity was assessed in three rearing conditions: 1) no food/no parasitisation permitted; 2) food/no parasitisation permitted; and 3) food provided after parasitisation. Adult wasp longevity was significantly higher in treatment 2 (21.1 days ± 4.1 SE) than in treatment 1 (3.6 days ± 0.5 SE) or 3 (3.8 days ± 0.6 SE). Laboratory tests carried out in this study on C. chamaeleon indicated high host selection ability, later confirmed by our post-release field data

Environmental Factors Impact and Incidence of Parasitism of Psyllaephagus Bliteus Riek (Hymenoptera Encyrtidae) on Populations of Glycaspis Brimblecombei Moore (Hemiptera Aphalaridae) in Mediterranean Climatic Areas

“…After the first record of P. bliteus in Sicily, its spread all over the region occurred in a short time, showing the high dispersal capacity. Similarly, Closterocerus chamaeleon (Girault), a parasitoid released in Sicily to control the eucalypt gall wasp Ophelimus maskelli (Ashmead) (Hymenoptera, Eulophidae) (RIZZO et al, 2015), rapidly spread through short and long distance dispersal mechanism, being widely distributed in the region after 18 months from its release in 2006(CALECA et al, 2011b.…”

The parasitoid Closterocerus chamaeleon has a greater development and survival rate than of its hosts, the Eucalyptus gall wasps Ophelimus eucalypti and Ophelimus maskelli in Sumatra, Indonesia

“…This parasitoid is recorded to have parasitised up to 100% of the galls induced by O. maskelli in Sumatra and led to a satisfactory capacity of the leaves to recover after the adult parasitoid emerged from its host (Tavares et al, 2021). Closterocerus chamaeleon individuals with food and no mating permitted showed a greater longevity (21.1 ± 4.1 days, mean ± SD) than those without food and no mating permitted (3.6 ± 0.5 days) and food provided after parasitism (3.8 ± 0.6 days) in a laboratory in Sicily, Italy (Rizzo et al, 2015),…”

A Review on Introduced Alien Insect Pests and Their Associated Parasitoids on Eucalyptus Trees in Sicily

“…Several studies have shown how both gall wasps currently appear to be successfully controlled by various biological control agents, especially hymenopteran parasitoids. Among them, three species were in fact released in Israel for the biological control of O. maskelli: Closterocerus chamaeleon (Girault) (Eulophidae), Stethynium ophelimi Huber and S. breviovipositor Huber (Mymaridae) (MENDEL et al, 2007) and the first one was also released in Italy (LAUDONIA et al, 2006;RIZZO et al, 2006RIZZO et al, , 2015. As regards L. invasa biological control, four species of parasitoids were released in Israel as well: (PROTASOV et al, 2008) but no information is available till now about their presence in Sicily.…”