New Records of Aphelinid Parasitoids (Hymenoptera: Aphelinidae) Attacking Soft Scale Insects on Ornamental Trees

Abstract

Aphelinid parasitoids play a crucial role in regulating soft scale insect populations in ornamental ecosystems, yet their diversity and host associations remain insufficiently documented in many regions. The present study reports new faunal records of aphelinid parasitoids associated with soft scale insects infesting ornamental trees in urban and peri-urban landscapes. Field surveys were conducted across multiple ornamental plantings, and infested plant parts bearing active scale colonies were collected for laboratory rearing and parasitoid emergence studies. Adult parasitoids emerging from parasitized scales were examined using morphological taxonomic keys, supported by microscopic characterization of diagnostic features including antennal segmentation, wing venation, and genital structures. Identified taxa were confirmed as belonging to key genera such as Encarsia and Coccophagus, representing new distributional and host association records for the region. Host scale insects primarily included members of Coccidae infesting ornamental species such as Ficus, Bougainvillea, and Hibiscus. Parasitism rates varied among host–parasitoid combinations, with higher activity observed under moderate temperature and humidity conditions favorable for parasitoid development. Observations indicated strong host specificity in certain aphelinid species, suggesting their potential utility in targeted biological control programs. The documentation of these new records expands the known biodiversity of aphelinid parasitoids in ornamental ecosystems and highlights their ecological significance in suppressing soft scale populations. These findings emphasize the importance of conserving native parasitoid complexes through reduced pesticide applications and habitat-friendly ornamental management practices. Overall, the study provides baseline information for integrating aphelinid parasitoids into sustainable pest management strategies in urban ornamental horticulture systems, contributing to environmentally safe and effective biological control approaches.