Predators of the two paropsine leaf beetles <i>Paropsisterna cloelia</i> and <i>Paropsis charybdis</i> in eucalypt plantations in Marlborough, New Zealand

Abstract Sustainable eucalypt forestry in New Zealand is compromised by two defoliating Australian paropsine beetles, Paropsis charybdis Stål and Paropsisterna cloelia (Stål) (both Coleoptera: Chrysomelidae). Egg and larval parasitoids provide inconsistent control; hence, predators present an additional integrated pest management tool. The community of arthropod predators present on Eucalyptus bosistoana F.Muell. (Myrtales: Myrtaceae) trees was defined in fortnightly abundance assessments from September to March over two consecutive growth seasons at a site in Marlborough. Subsequently, predatory taxa feeding on the two pest beetles were identified and their predation activity estimated by combining quantitative PCR (qPCR) analysis of field‐collected predators (i.e., percentage of individuals testing positive for each predator taxon) and field observations of predation events. The paropsine predator community consisted of three Coccinellidae (Coleoptera) species, one Miridae (Hemiptera), one Hemerobiidae (Neuroptera), one Pentatomidae (Hemiptera), one Anystidae (Acari), one Erythraeidae (Acari) and the three spider families Araneidae, Oxyopidae and Salticidae (Araneae). Oechalia schellenbergii (Guérin) (Hemiptera: Pentatomidae) and Cleobora mellyi (Mulsant) (Coleoptera: Coccinellidae), both naturally occurring in Australia, were the most promising candidates for the support of future paropsine control in New Zealand. Oechalia schellenbergii was the most abundant predatory insect and the most active predator, with 100% of individuals testing positive for the paropsines, and the only predator taxon that fed as both immatures and adults on all paropsine life stages. Cleobora mellyi was the second most active predator, with an estimated 87% of individuals testing positive for paropsines. The results also highlight spiders as paropsine predators, especially the abundant family Araneidae. In conclusion, augmentative or conservation biocontrol using O. schellenbergii and Cl. mellyi is a promising integrated pest management opportunity. Research on methods to achieve this in plantations is required.