Identification of Aulacaspis yasumatsui found on Amami-Oshima Island and its damage to Cycas revoluta

Abstract

In 2022, mass yellowing of Cycas revoluta leaves caused by a scale occurred on Amami-Oshima Island. We identified the scale as Aulacaspis yasumatsui, a worldwide cycad pest. The occurrence was reported as the first record of the A. yasumatsui in Japan. In this paper, we report on the identification details and the survey on the distribution and damage in the Amami Islands. We identified the scale based on its morphological characteristics and then confirmed the identification based on its nucleotide sequences of COI and COII regions of mitochondrial DNA. The nucleotide sequence of COI barcode region (630 bp) in our sample from Amami-Oshima Island is 100% identical to that from Fujian Province in China previously reported. The scale was found in Amami City, Tatsugo Town, Yamato Village and Uken Village. In C. revoluta, where this scale occurs, the leaves ranged from those with no yellowing to those with all leaves yellowed. Severe damage, such as yellowing of all the leaves, and mass yellowing was concentrated in near the Naze Port in Amami City.