Can pests combined cause yield reduction and sugar quality losses?

The sugarcane borer and spittlebug are considered important sugarcane pests in South America. Damage caused by these pests has already been studied. However, this information was obtained for each species separately. Thus, knowledge on plant response to these two pests combined as well as the effect on sugarcane products are not completely understood yet. Therefore, the aim of this work was to evaluate the sugarcane plant response under the infestation of these two biotic stressors. Thus, the treatments included sugarcane infested by each pest separately, sugarcane infested by both pests and control (uninfested). Plants were kept under screened cage (m²) in field conditions. There was a reduction in the sugarcane stalk yield due to the attack of spittlebug nymphs (15.74%), spittlebug nymphs + sugarcane borer (44.23%) and sugarcane borer (11.19%), compared to the control (caged). These pests also affected sugar quality. The sugar produced from infested plants presented higher content of phenolic compounds. These compounds increased the a sugar colour level (ICUMSA), mainly when the pests were together. Thus, the infestation of these pests combined lead to yield reduction and sugar quality losses.