Occurrence of Cicadulina bipunctata (Hemiptera: Cicadellidae) in southwestern Shikoku, Japan and comparisons of gall-inducing ability between Kyushu and Shikoku populations

The maize orange leafhopper Cicadulina bipunctata (Melichar) is an insect pest of cereal crops in tropical and subtropical regions of the Old World. This leafhopper induces gall symptoms characterized by stunted growth and swollen leaf veins on various Poaceae. Damage by C. bipunctata has been reported from Australia, the Philippines, China, Taiwan, and Japan. In Japan, C. bipunctata occurs in the central and southern parts of Kyushu. Because the leafhopper is a potential pest of various cereal crops, we conducted field surveys in Shikoku and the southern part of the Kii Peninsula (a part of Honshu), where the climate seems to be suitable for the establishment of C. bipunctata. As a result, we found C. bipunctata at some localities in Ehime and Kochi Prefectures. This is the first record of this leafhopper from Shikoku. Our laboratory experiment revealed that a Kochi population of C. bipunctata had a gall inducing ability similar to the Kumamoto population. More attention should be paid to assessing the risk of further expansion of C. bipunctata populations in Shikoku.