ABSTRACT The Box Tree Moth (BTM), Cydalima perspectalis (Walker) (Lepidoptera: Crambidae), is a major pest of Buxus spp., native to Asia and established in Europe since 2007. It causes severe damage to ornamental and natural boxwood stands, posing a significant risk to protected natural habitats. Given that chemical and microbiological control measures are often restricted or prohibited in these sensitive environments, interest has shifted toward native natural enemies. Among these, tachinid parasitoids represent a viable alternative for sustainable biological control. In this study, we evaluated host acceptance, host‐associated mortality, and developmental performance of Exorista larvarum (L.) (Diptera: Tachinidae) on last instar BTM larvae, using the factitious host Galleria mellonella (L.) (Lepidoptera: Pyralidae) as a control. Laboratory bioassays were conducted using no‐choice and choice (1:1 and 5:5) experimental designs. Specifically, host acceptance, larval mortality, puparium formation, adult emergence and egg load were quantified. E. larvarum females readily accepted BTM larvae, particularly in the no‐choice and choice (5:5) tests, causing high parasitoid‐associated mortality (> 70%). However, oviposition frequency and subsequent developmental success were significantly lower on BTM than on G. mellonella . In both choice tests, parasitoid females exhibited a marked preference for the factitious host. Furthermore, while the development of E. larvarum on BTM was constrained, a limited number of adults successfully emerged, demonstrating, for the first time, that complete development on BTM is occasionally possible. Although our laboratory findings provide promising evidence of the suppressive potential of E. larvarum against BTM, its actual field‐scale efficacy remains to be validated. Nevertheless, it deserves consideration as a viable component of augmentative and conservation biological control programmes, especially in sensitive habitats where conventional control methods are restricted.
Gallizia et al. (Tue,) studied this question.