Claudia Echeverri-Rubiano, Gerson Ramírez and Carolina Camargo
Cenicaña Estación Experimental, Cali, Colombia; cecheverri@cenicana.org
Stemborers of the genus Diatraea are the main pests of sugarcane in the Cauca River Valley, Colombia, with four species of economic importance: D. saccharalis, D. indigenella, D. busckella,and D. tabernella. Monitoring these sugarcane borers up to 3.5 months into the crop cycle is essential to understand the dynamics of the pests and their parasitoids in this region. In this study, 6,506 fields were monitored in 2016, 2019, 2022, and 2023 to identify the changes in temporal and spatial distribution of Diatraea spp. populations, as well as the effectiveness of parasitoids. The analysis revealed a turnover in the distribution of Diatraea species: D. saccharalis and D. indigenella dominated sugarcane fields in the valley in 2016, while the most common species were D. busckella and D. tabernella in 2019, 2022, and 2023. In addition, a change was observed in populations of larval parasitoids, with Lydella minense being the most dominant species in 2016, while the wild tachinid fly Genea jaynesi and the reared wasp Cotesia flavipes were the predominant species in 2023. The three parasitoid species interact with the four Diatraea species, but in variable proportions, which allows mills to establish the parasitoid effectiveness. Based on the parasitism results, an increase in the release rates of C. flavipes and L. minense were proposed in outbreak areas. Given that G. jaynesi cannot be reared, the establishment and conservation of broadleaf weeds is recommended to provide nectar and shelter to this natural enemy and other beneficial arthropods in sugarcane.