Journal article
First Report of Scab Disease Caused by Venturia effusa on Pecan in Anhui Province of China
Plant disease, Vol.107(5)
2023
Abstract
Pecan (Carya illinoinensis) is a world-famous nut tree widely cultivated in China. Quanjiao County, located in Anhui Province, is reputed to be the capital of pecan production in China. Since 2019, typical scab symptoms were observed on most pecan cultivars in orchards located in the regions of Quanjiao (32°5′7.08″N, 118°16′2.91″E). In April 2019, dark brown to black lesions of scab were observed on abaxial and adaxial surfaces of the lamina, and were often associated with the veins or midrib. In July, small, brownish, circular lesions 1 to 2 mm in diameter were observed at the end of stems and shoulder of the fruit. In surveyed orchards, disease incidence on leaves reached more than 35%. According to the number of infected nut clusters, disease incidence ranged from 40 to 60% on the infected fruits. Using a sterilized scalpel, conidia were scraped from the surface of a single lesion from the infected leaves or fruits, and a dilute spore suspension was prepared in sterile distilled water, of which 100 μl was spread on 1% water agar plate (Bock et al. 2014). The conidia were incubated at 25°C for 48 h under fluorescent lights with a 12-h photoperiod. Single germinated conidia were selected and transferred into potato dextrose agar (PDA) plate to obtain monospore isolates. From 2019 to 2020, more than 20 isolates were obtained from the infected leaves and fruits. After incubation at 24°C for 6 weeks in darkness on PDA, the colonies were gray-black with circular morphology and floccose texture, which were consistent with the characteristics of Venturia effusa described previously (Gottwald 1982). The conidia were pyriform to ellipsoid, zero to one septate, smooth, attenuated toward apex and base, base truncate, pale brown, and 10.08 to 18.14 × 4.86 to 9.56 μm (n = 50) in size. To further identify the isolates, the regions of internal transcribed spacer (ITS), beta-tubulin 2 (TUB2), and translation elongation factor 1 alpha (EF1-a) were amplified and sequenced from genomic DNA for the three representative isolates (AH-81 and AH-82 from the infected leaves, and AH-41 from the infected fruits), respectively (Bensch et al. 2006; White et al. 1990; Young et al. 2018). Sequences of them were deposited in GenBank under nos. OP199056 to OP199058 (ITS), OP566581 to OP566583 (TUB2), and OP566578 to OP566580 (EF1-a). Multilocus phylogenetic analysis revealed that three isolates and V. effusa were clustered in the same clade, indicating high genetic similarity between these organisms. Their morphological and molecular characteristics were consistent with those for V. effusa. The pathogenicity of three isolates were tested on 2-year-old container-grown pecan seedlings, which were grown in the nursery. The conidial suspension with a concentration of 5 × 105 conidia/ml was sprayed evenly on the surface of leaves of a healthy pecan seedling, and each isolate inoculated four pecan seedlings. The pathogenicity experiment was repeated three times. Plants inoculated with sterile water were used as negative controls. Inoculated plants were enclosed in plastic bags for 2 days and kept in the nursery greenhouse. Four weeks after inoculation, a similar symptom of scab was observed on leaves of cultivar Mahan, and V. effusa was isolated from all inoculated leaves by single-spore isolation, whereas no symptoms were observed on the control plants. To our knowledge, this is the first report of V. effusa as a scab pathogen on pecan in Anhui Province of China and underscores the need for monitoring this disease and developing disease control strategies to prevent severe reduction in the value of fruit.
Details
- Title
- First Report of Scab Disease Caused by Venturia effusa on Pecan in Anhui Province of China
- Authors/Creators
- Keer Zhuo - Nanjing Agricultural UniversityCancan Zhu - Institute of Botany Jiangsu Province and Chinese Academy of Sciences, 101674, Nanjing, Jiangsu, China;Yongdong Gao - Shanghai Agricultural Technology Extension and Service Center, Shanghai, Shanghai, China;Hao Luo - Chuzhou, Anhui, China;Yu Chen - Institute of Botany Jiangsu Province and Chinese Academy of Sciences, 101674, Nanjing, Jiangsu, China;Shijie Zhang - Institute of Botany Jiangsu Province and Chinese Academy of Sciences, 101674, Nanjing, Jiangsu, China;Wu Wang - Institute of Botany Jiangsu Province and Chinese Academy of Sciences, 101674, Nanjing, Jiangsu, ChinaXiaomei Lu - Changzhou Guomei Agricultural Technology Co., Ltd., Chanzhou, China;Yanli Tian - Nanjing Agricultural UniversityBaishi Hu - Nanjing Agricultural UniversityYuqiang Zhao - Institute of Botany Jiangsu Province and Chinese Academy of Sciences, 101674, 1 Qianhuhoucun Road, Nanjing, Jiangsu, China, 210014;
- Publication Details
- Plant disease, Vol.107(5)
- Publisher
- The American Phytopathological Society
- Identifiers
- 991005570077907891
- Copyright
- © 2023 The American Phytopathological Society
- Murdoch Affiliation
- Centre for Crop and Food Innovation
- Language
- English
- Resource Type
- Journal article
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