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MD2 pineapple production in the Valle del Cauca Department, Colombia, has increased in recent years due to its preference in the national and international markets. Pineapple mealybug wilt (PMW), reported in all production areas around the world, is associated with two mealybug species, Dysmicoccus brevipesand D. neobrevipes, and a group of virus species known as pineapple mealybug wilt-associated viruses (PMWaVs). In a previous study, D. brevipeswas determined to be the main mealybug species associated with pineapples in the region; hence, the objective of this study was to determine the occurrence and distribution of PMWaVs in pineapple plants and specimens of D. brevipescollected in five MD2 pineapple fields in the Department of Valle del Cauca. Our results confirmed the presence of three virus species in both plant and mealybug specimens. PMWaV3 showed the highest detection frequencies (92.6% and 88.7%), followed by PMWaV1 (26.5% and 8.3%) and PMWaV2 (12.0% and 2.0%) in plant and mealybug samples, respectively. Mixed infections of PMWaVs were found also in the studied plant material. The most common virus association consisting of PMWaV1 and PMWaV3 was found in 30 plant samples (20%). The correlation analysis between each virus species found in mealybugs and their pineapple host suggests that PMWaV3 is not only transmitted through infested plant material, but that D. brevipesmay also play a role in the dynamics of disease dissemination. The results of this study contribute to the understanding of PMWaV transmission in MD2 pineapple-cultivated areas in the Valle del Cauca region.

•Biological control (BC) is a desirable, nature-based alternative to synthetic pesticides.•Beneficial insects restore ecological regulation of invaded agro-ecosystems.•By lifting crop yields, BC resolves malnutrition, rural poverty and economic hardship.•Trans-disciplinary research can elucidate net positive social-ecological outcomes.

Background: The insect vector of Huanglongbing, Diaphorina citriKuwayama, 1908 (Hemiptera: Lividae) was detected in Ecuador in 2013 and its main parasitoid Tamarixia radiata(Waterston, 1922) (Hymenoptera: Eulophidae) was reported for the first time in 2017. In the citrus production region of Manabí province, Ecuador, D. citriand T. radiatawere reported for the first time on Murraya paniculataL. in 2016 and 2018, respectively. D. citriwas first found infesting Citrus x aurantiifolia(Christm.) Swingle in Manabí province at the end of 2018. The present study was conducted between August 2018 and May 2021 to: (1) monitor D. citripopulations on M. paniculataand C. x aurantiifoliaand determine the parasitism rates of T. radiataon D. citrinymphs on both host plants, (2) establish the occurrence of T. radiataparasitizing D. citrion C. x aurantiifolia, and (3) calculate a predictive model for estimating the number of parasitized nymphs on a planting lot of M. paniculataand a C. aurantiifoliaorchard. Results: Diaphorina citripopulations on M. paniculatadecreased from 11 nymphs (2018–2019) to approximately 2 nymphs per flush (2020). This was associated with a natural increase in parasitism rates of T. radiatafrom 20% (2018) to 96% in 2020. The regression equation (Y= 2.049Ln (x) + 5.88) was able to estimate the number of parasitized D. citrinymphs based on parasitism on M. paniculata(R2: 0.8315). Tamarixia radiatawas first detected on C. x aurantiifoliain July 2020. Populations of D. citrireached 55 nymphs per flush (no parasitism) and subsequently decreased to the minimum level of 14 nymphs per flush (parasitism rates of up to 31%). The model allowed estimating the number of parasitized nymphs by T. radiataon M. paniculataand C. x aurantiifolia, with a maximum deviation of approximately 2 nymphs. Conclusions: Based on the colonization and establishment of the psyllid–parasitoid interaction on M. paniculata, it is estimated that approximately by the end of 2022, populations of D. citrion C. x aurantiifoliawould decline due to the highest percentages of parasitism by T. radiata. High parasitism rates may indicate the potential of T. radiatain conservation biological control and integrated pest management programs.