A Wide and Heavy Infestation with Leptotrombidium scutellare Larvae in the Western Part of Kanagawa Prefecture, Japan (Trombidiformes, Trombiculidae)

Abstract

Based on the previous data (Uchikawa et al., 1994), we presumed that Leptotrombidium scutellare larvae were distributed widely in man-made environments around densely populated areas inwestern Kanagawa Prefecture, Japan. Employing modified Suzuki's visual sampling method (Uchikawa et al., 1993), this assumption was examined during the period between November 4 and 6, 1993, in Yamakita Town and Minamiashigara City, Kanagawa Prefecture. The above assumption was verified, indicating at the same time that the method was appropriate for our purpose. Many L. scutellare larvae were frequently found on shaded and humid places but not on dry soil surface. Very heavily infested places were encountered in mandarin orange groves and, unexpectedly, in a young kiwi fruit orchard surrounding the center of Yamakita Town with crowded dwellings, and in mandarin orange groves on gently rolling hills of Minamiashigara City. As many as 9, 658 unfed larvae to use in other analyses were taken on sampling and collecting pieces of black cloth during the survey. These larvae were observed to have stayed still in clusters on the cloths sealed in plastic bags that had been kept in a container since the previous day.