Examining baculovirus ecology for enhancing microbiological control strategies against Cydalima perspectalis

Abstract: Cydalima perspectalis (Walker), box tree moth (Lepidoptera, Crambidae), is an
invasive species native to Asia, which has become one of the most damaging pests of
ornamental and natural boxwood (Buxus sp.). In Spain, BTM expansion seriously threatens the Pyrenean boxwood grove, an integral part of many habitats of priority ecological interest. New approaches to microbiological control in forestry are moving towards proactive measures to control invasive pests, such as the inoculation of disease agents. Baculoviruses (Baculoviridae) have a high potential for this purpose due to their high specificity, environmental persistence in forest ecosystems and transgenerational transmission. In this study, we evaluated the potential of baculovirus (Bvs) isolates from box tree moth (BTM) populations in natural box tree areas as microbial control agents. Out of 630 field-collected larvae, 27 individuals developed a full Bvs infection. Field-collected survivors were continuously breeding over five generations (F1-F5) and led to the obtention of 159 Cype Bvs isolates. These isolates were obtained after spontaneous Bvs infections in the BTM line, which eventually collapsed. The genotypic structure of the viral population was analyzed using Restriction Fragment Length Polymorphism (RFLP) with endonucleases PstI, HindIII and EcoRI revealing at least 3 genotypic variants, either single or combined in the same isolate. Additionally, vertical transmission of the virus was confirmed by detecting its presence in adults of each generation using qPCR, demonstrating its capacity for long-term persistence within the host population.