Ecological dynamics of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) and its parasitoids in varied host environments

The mealybug Phenacoccus solenopsis Tinsley has emerged as a widespread and detrimental pest in Moroccan crops. This study investigated the interactions between this mealybug species and its parasitoids, Leptomastix epona (Walker), Anagyrus dactylopii (Howard) and A. aligarhensis Agarwal and Alam (Hymenoptera, Encyrtidae), with a focus on field surveys and functional response dynamics. Field surveys were conducted over 3 years (2021–2023) on Portulaca oleracea (L.), Medicago sativa L. (Fabaceae), and Opuntia megacantha Salm-Dyck (Cactaceae) in Morocco. Functional response and interference experiments were conducted under laboratory conditions to understand parasitoid behaviors and their impact on mealybug populations. Percentages of infestation increased significantly from 2021 to 2023 in the field. In 2023, infestation percentages were 98.7% ( P. oleracea ), 56.7% ( M. sativa ), and 47.3% ( O. megacantha ). Parasitism rates by L. epona in P. solenopsis ( P. oleracea ) increased from 42.63% (2021) to 51.8% (2023), while they declined for A. aligarhensis from 27.73% to 20.86%, and they slightly decreased for A. dactylopii from 29.63% to 27.39%. Functional response trials indicated a type II functional response for all parasitoids, with L. epona demonstrating superior attack rates (0.92 h −1 ) and search efficiency (0.90). Handling time was consistent across all three parasitoids (0.04 h). For L. epona , the mutual interference constant ( m ) was estimated to be 2.20, while it was estimated at 2.07 for A. dactylopii , and at 1.99 for A. aligarhensis . These findings contribute to enhancing our understanding of the intricate relationships between the invasive mealybug P. solenopsis and its parasitoids, with potential implications for sustainable pest management strategies.