<p>Armored scale insects (Hemiptera: Diaspididae) have been identified as pests worldwide. In Costa Rica, <i>Diaspis boisduvalii</i> Signoret is a primary insect pest in banana plantations, causing substantial economic losses and high control costs. In order to identify the parasitoids (Hymenoptera) and determine the influence of insecticide and herbicide use on percent parasitism of <i>D. boisduvalii</i> on banana (<i>Musa</i> AAA “Cavendish”) in Costa Rica, six commercial plantations with varying insecticide and herbicide use were sampled over a five-month period. Petioles from the oldest leaf infested with scale insects were collected monthly at each site. Each petiole fragment (55 cm²) was stored in a well-ventilated glass tube and monitored daily for parasitoid emergence, percent parasitism, and sex ratio. Four parasitoid species were identified: a gregarious ectoparasitoid <i>Aphytis</i> sp., a solitary endoparasitoid <i>Coccobius</i> sp. (Aphelinidae), another solitary endoparasitoid <i>Plagiomerus peruviensis</i> (Girault) (Encyrtidae) and a hyperparasitoid <i>Ablerus</i> sp. (Azotidae). These are the first records of an association between <i>D. boisduvalii</i> and <i>Aphytis</i>, <i>Coccobius</i> and <i>Ablerus</i>. The study revealed that high insecticide use had a significant negative impact on percent parasitism, while herbicide effects were species-specific and only evident under low insecticide use. Rather surprisingly, <i>P. peruviensis</i> exhibited higher percent parasitism in plantations with low insecticide use but with herbicide use, unlike the other parasitoids. Results from sex ratios suggest that <i>P. peruviensis</i> reproduces via thelytokous parthenogenesis and the other parasitoids via arrhenotokous parthenogenesis. It is important to explore the selectivity of each pesticide used in banana plantations to parasitoids in order to achieve successful biological control.</p>