Cryphalus eriobotryae: a new pest of loquat in China
In April 2018, several loquat (Eriobotrya japonica) trees were attacked and killed by an unknown bark beetle in a commercial plantation in Suzhou (Jiangsu province), China. This was initially considered as an incidental and natural mortality, but more trees growing nearby were also killed by the same pest from August to October 2018. Investigations revealed the presence of a previously undescribed bark beetle species, Cryphalus eriobotryae sp. nov. (Coleoptera: Curculionidae: Scolytinae). Surveys carried out from May 2018 to May 2019 in the area of Suzhou showed that C. eriobotryae occurred in several localities and has already killed more than 1000 loquat trees. Attacks by C. eriobotryae can be detected by the presence of small (< 0.8 mm) circular entrance holes (sometimes hidden in bark crevices) and frass, followed by the development of surrounding necrotic tissue (cankers) on the bark of the trunk and branches around these entrance holes. It is noted that there were no obvious signs of a fungal pathogen, but that the presence of pathogens has not been systematically investigated.
A study of plantation records in the area of Suzhou has suggested that this beetle was introduced from another area not long before 2017. Given the distribution of the plant genus Eriobotrya and the distribution of similar Cryphalus species, it is suspected that the beetle is native to East or Southeast Asia. According to local farmers, rootstocks were imported from other regions of China in 2017, which could have been a pathway for introducing C. eriobotryae in the area of Suzhou.
Sources
Zheng S, Johnson AJ, Li Y, Chu C, Hulcr J (2019) Cryphalus eriobotryae sp. nov. (Coleoptera: Curculionidae: Scolytinae), a new insect pest of loquat Eriobotrya japonica in China. Insects 10(6), 180. https://doi.org/10.3390/insects10060180 |