Sustainable Pest Management in Peri-Urban Andean Agroecosystems: Integrating Ecotype Selection, Chemical Control, and Environmental Impact Assessment for Tree Tomato (Solanum betaceum) Production

The bacterial pathogen Candidatus Liberibacter solanacearum (CLso), transmitted by the potato psyllid Bactericera cockerelli, causes purple tip disease, a major threat to tree tomato (Solanum betaceum) production in peri-urban Andean highlands. This study evaluated an agroecological approach integrating host resistance, chemical control, and environmental impact assessment in Salache, Cotopaxi, Ecuador (2710 m a.s.l.). Three bactericide strategies (nursery + field, field-only, untreated control) were tested across six ecotypes using a factorial design. CLso detection was performed by PCR, vector populations were monitored weekly, agronomic traits were recorded monthly, and environmental impact was assessed via the Leopold matrix. PCR results confirmed CLso presence in seeds and nursery seedlings, but all field samples were negative across all treatments, including the untreated control. Notably, the untreated control (A0) showed significantly greater plant height and leaf number than bactericide-treated plots (p < 0.01). Three ecotypes (BQ_sana, Atuntaqui, Granel) exhibited superior agronomic performance (greater plant height, stem diameter, and leaf number) under the conditions of this study, suggesting potential tolerance that warrants further investigation under confirmed disease pressure. Chemical control generated a substantial negative environmental impact (negative score −214; positive score +54; net −160), mainly affecting soil, air quality, and beneficial fauna. An integrated agroecological strategy combining resistant ecotypes, threshold-based insecticide rotation, and physical barriers such as yellow sticky traps is recommended to reduce environmental harm while ensuring sustainable tree tomato production in peri-urban Andean agroecosystems.