In 2022, a stiff fruit disease was found on seedless litchi in Hainan, which was obviously different from the common litchi diseases in Hainan, such as anthracnose and acid rot. It mainly damaged young fruits. There was no significant change in the appearance of young fruits when the disease occurred. When the fruit was broad bean, the outer peel of the diseased fruit became darker, and the inner peel became irregularly brown after dissection. The fruit no longer expanded, forming fleshless stiff fruit, which was easy to cause serious economic losses. In this study, the pathogen of the disease was isolated, identified, invasion way and rapid detection techniques were studied. The pathogen was identified as Fusarium pernambucanum by morphological identification, ITS, RPB2 and TEF1 gene sequence analysis. The pericarp of seedless litchi fruit at young fruit stage was susceptible to pathogen invasion after being damaged by farming operations, wind, piercing-sucking insects, while the fruit surface was not diseased without wounds. The main invasion period of the pathogen was 3.2-4.8 mm in the longitudinal direction of the fruit. After the fruit was bigger than 9.8 mm, the probability of pathogen invasion gradually decreased. Based on the TUB gene sequence, the specific primers for rapid detection of F. pernambucanum were obtained, and a rapid and efficient molecular detection method based on ordinary PCR was constructed. The detection method is sensitive and efficient, and would provide support for early diagnosis and prevention of seedless litchi stiff fruit disease.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |