Apple canker has decreased yields of the economically important apple (Malus domestica) crop in China in recent years. Pathogen identity is highly challenging and the disease is poorly understood. Specimens of 339 fungi were isolated from apple trees in the primary apple-producing region in the Tarim Basin during the current study. In total, nine species of Cytospora and five species of the family Botryosphaeriaceae were identified by morphological observation and multilocus phylogenetic analyses: internal transcribed spacer (ITS), actin, translation elongation factor (TEF), and β-tubulin (TUB) gene regions for Cytospora and ITS, TEF, and TUB for Botryosphaeriaceae. Cytospora pyri from the Cytospora genus was the dominant species causing apple canker in the Tarim Basin. C. melnikii, C. tritici, C. euonymina, Diplodia seriata, and Botryosphaeria dothidea have been described as the cause of apple canker in China. Apple (Red Fuji) branches were utilized to assess the pathogenicity of 24 representative fungal isolates from the 14 species, and branches from seven distinct woody plants (Korla pear, walnut, Chinese date, Xinjiang poplar, sand jujube, Populus euphratica, and willow) were utilized to analyze the host range. The main pathogenic fungal species of apple canker around the Tarim Basin were identified and biological characteristics explored. Pathogen diversity and regional source diversity were assessed with host range and pathogenicity. The aim was to provide a theoretical foundation for the prevention and treatment of apple canker.

Lygus pratensis, an important agricultural pest, is seriously detrimental to cotton in China. For the research and development of attractants, the present study screened and identified plant volatiles with activity against the pest. Out of the total 20 volatiles identified from seven hosts, 16 volatiles were selected and evaluated. Electrophysiological test results revealed the highest electroantennogram values of heptacosane, heptadecane, decanal, (E)-4-hexen-1-ol, dodecane, β-pinene, and cis-3-hexenyl isovalerate on adult insects. A significant difference in the behavior of female adults (P < 0.01) was noted in the trend behavioral tests when the concentration of heptacosane, nonadecane, heptadecane, decanal, 3-hexen-1-ol, and dodecane was 10⁻³ (V/V), and that of β-pinene was 10⁻⁴ (V/V). The field trapping test confirmed a significant difference in the trapping effect of heptadecane at 10⁻² (V/V) and 10⁻³ (V/V), decanal at 10⁻¹ (V/V) and 10⁻³ (V/V), β-pinene at 10⁻² (V/V), and dodecane at 10⁻⁴ (V/V) compared to that of other volatiles (P < 0.05). These findings suggested the strong attractant effect of heptadecane, dodecane, decanal, and β-pinene on adults, indicating their potential application as effective attractants for the ecological control of L. pratensis.

Apple (Malus pumila Mill.) is an important fruit crop in Xinjiang, China. In September 2021, apple tree canker was observed in a 21-year-old commercial apple orchard cv. Fuji in Xinjiang (38°17'51....

The plant pathogenic fungus Cytospora is notoriously known for causing woody plant canker diseases, resulting in substantial economic losses to biological forests and fruit trees worldwide. Despite their strong negative ecological impact, the existing and prospective distribution patterns of these plant pathogens in China, according to climate change, have received little attention. In this study, we chose three widely dispersed and seriously damaging species, namely, Cytospora chrysosperma, Cytospora mali, and Cytospora nivea, which are the most common species that damage the Juglans regia, Malus domestica, Eucalyptus, Pyrus sinkiangensis, Populus spp., and Salix spp. in China. We utilized ecological niche modeling to forecast their regional distribution in China under four climate change scenarios (present, SSP 126, SSP 370, and SSP 585). The results show that temperature-related climate factors limit the current distribution ranges of the three species. Currently, the three studied species are highly suitable for northeast, northwest, north, and southwest China. Under future climate scenarios, the distribution ranges of the three species are projected to increase, and the centers of the adequate distribution areas of the three species are expected to shift to high-latitude regions. The three species coexist in China, primarily in the northwest and north regions. The ecological niches of C. chrysosperma and C. nivea are more similar. The distribution range of C. mali can reach the warmer and wetter eastern region, whereas C. chrysosperma and C. nivea are primarily found in drought-prone areas with little rainfall. Our findings can help farmers and planners develop methods to avoid the spread of Cytospora spp. and calculate the costs of applying pesticides to reduce contamination and boost yields.

Pear Valsa cankers were found in various Korla fragrant pear orchards in Alaer, Xinjiang. Disease samples underwent tissue isolation, resulting in six isolates. Pathogenicity tests revealed that the XLFL-6 isolate was the most virulent, demonstrating typical Valsa canker symptoms. Research on its biological characteristics indicated that the optimal growth conditions for XLFL-6 were a temperature of 28 °C and a pH of five. Under these conditions, the colonies of XLFL-6 exhibited the largest growth diameter, and adding glucose and peptone separately to the Czapek medium was most conducive to the growth of its mycelium. Based on morphological observations and multigene sequence analyses (ITS+TEF+TUB), the pathogenic fungus was identified as C. pyri. The infection process of C. pyri was elucidated through tissue observations using both light and electron microscopy. The conidia displayed a similar germination pattern on both wounded and intact twigs. However, the infection process was delayed in the case of intact bark. By 8 h post-inoculation, the conidia achieved a germination rate of 15%. Although germination had occurred, the infection process had not yet commenced. In contrast, for wounded bark tissue, it was observed that 24 h post-inoculation, the fungal hyphae from the conidia directly invaded the wounded tissue. These hyphae penetrate the cell walls, proliferate within the host tissue, and spread throughout the phloem and xylem. After 20 d, numerous pycnidia had breached the bark surface, and yellow waxy gums filled with conidia flowed abundantly from the pycnidia ostioles, with the host tissue being nearly totally disintegrated. Regarding enzyme activity, the polygalacturonase (PG) activity, the primary cell wall-degrading enzyme in the treatment group, was seven times greater than that of the control group. The carboxymethyl cellulose (Cx) activity within the treatment group continued to increase. Xylanase activity rose swiftly to its peak between days 1 and 4, then decreased from days 5 to 10, although it remained higher than that of the control group. Overall, this study is the first to provide a detailed report on the characteristics and proliferation of C. pyri and further elucidates its modes and pathways of invasion.