Behavior and injuries of phytophagous mites on apple trees (Malus domestica: Rosaceae)

Abstract

Abstract This study aimed to assess the behavior of phytophagous mites, including conspecific and heterospecific effects, and the injuries caused by them at different population levels on apple tree leaves (Malus domestica: Rosaceae). The oviposition of Panonychus ulmi (Koch) was evaluated on apple tree leaves with the presence of webs, eggs, and cues of phytophagous mites (Aculus schlechtendali (Nalepa), P. ulmi, Tetranychus urticae Koch, and Tetranychus ludeni Zacher). The response to different infestation levels of P. ulmi, T. urticae, and T. ludeni on apple tree leaves was assessed through chlorophyll A, B, and total chlorophyll indices and membrane stability loss. The presence of conspecific webs and cues increased the oviposition of P. ulmi, while the presence of A. schlechtendali and T. urticae webs and eggs decreased oviposition. The presence of A. schlechtendali cues also led to a decline in P. ulmi oviposition. Leaves infested with T. urticae showed higher chlorophyll loss, leaves infested by P. ulmi and T. ludeni had decreased chlorophyll averages in treatments with 25 mites/leaf and above. The evaluation of membrane stability loss identified T. ludeni as a potential cause of injuries in apple trees. The evaluations indicated that the higher the number of mites on the leaf surface, the larger the damaged area. This work warning to the apple production chain for monitoring infestations and preventing a potential threat to culture. These results provide a foundation for further research on the potential of apple tree phytophagous mites and their interactions, both among herbivores and with predators.