Kazakhstan is recognized as one of the primary centers of origin of the wild apple Malus sieversii, concentrated mainly in the mountains like Trans-Ile and Zhongar Alatau, as well as parts of the Tarbagatay, Talas Alatau, and Karatau ranges. As the wild progenitor of Malus domestica, M. sieversii harbors a critical genetic diversity essential for apple breeding and conservation efforts. However, its natural populations are increasingly threatened by latent viral infection, which weakens trees, reduces reproduction, and hinders regeneration. In this study, the spread of apple chlorotic leaf spot virus (ACLSV) and apple stem pitting virus (ASPV) was documented in four wild apple populations, with detection rates of 50.2% and 42.2%, respectively. Mixed infections were observed in 28.8% of sampled trees. Apple stem grooving virus (ASGV) was detected exclusively in cultivated orchards, whereas apple mosaic virus (ApMV) and apple necrotic mosaic virus (ApNMV) were not found in either wild forests or cultivated orchards. Using Geographic Information System (GIS) technology, we developed the first spatial distribution maps of these viruses in wild apple forests in the Tian Shan region, revealing site-specific variation and infection rates. These results underscore the importance of monitoring viral infections in wild M. sieversii populations to preserve genetically valuable, virus-free germplasm critical for apple breeding, crop improvement, and sustainable orchard management.

Fungal pathogens, particularly representatives of the genera Moniliniaand Venturia, pose a serious threat to apple (Malus domestica) production in temperate climate regions. Among them, Moniliniaspecies cause moniliosis (brown rot), while Venturia inaequalisis the causal agent of apple scab—both diseases result in significant economic losses and reduce fruit quality in orchards.Moniliniaspecies are known as pathogens responsible for fruit rot, blossom blight, and shoot dieback. In recent years, the invasive species M. polystromahas attracted researchers' attention due to its high aggressiveness and expanding range in European apple orchards. These pathogens cause round, sunken necrotic lesions on fruits with active sporulation, leading to fruit mummification and the persistence of infection within the orchard.In turn, Venturia inaequalisremains one of the most widespread and damaging pathogens of apple, particularly in cool and humid climates. It primarily affects leaves and young fruits, causing characteristic olive-brown to black spots thatcan lead to premature leaf fall, fruit deformation, and a reduction in commercial value.The present study presents the results of a field survey aimed at detecting and preliminarily identifying Moniliniaand Venturiapathogens based on the evaluation of visible disease symptoms in cultivated apple orchards. The obtained data help clarify the species composition and visual manifestation of major fungal diseases in the agroecosystems of the Almaty Region. These findingsare important for improving phytosanitary monitoring and developing integrated plant protection strategies for sustainable apple production