<p><strong>Determination of seasonal changes of spider mite (Acari: Tetranychidae) densities and species composition on kudzu vine and soybean (Fabaceae) in Japan with the use of phosphoglucomutase zymograms*</strong></p>

Abstract

Identification of spider mites based on morphological characteristics is difficult because morphological differences between species may be subtle and in some groups, including the Tetranychus Dufour species, detectable only in adult males, which usually correspond to a small proportion of a population. The utility of an alternative method, phosphoglucomutase (PGM) zymogram, is demonstrated in this study. Using this method, we were able to discriminate females of each of 13 known Japanese Tetranychus species. We examined the species composition and seasonal density changes on kudzu vine [Pueraria montana var. lobata (Willd.) Sanjappa and Pradeep], a fabaceous weed, between 1997 and 1999, and on soybean [Glycine max (L.)] between 1999 and 2001. On kudzu vine, spider mite populations showed two types of seasonal fluctuation, one characterized by a single peak in September or October and the other by two peaks, in June and September. Five spider mite species were found on this plant species, with T. pueraricola Ehara &amp; Gotoh being dominant throughout the 3-year period and accounting for 75.6–96.9% of all females. On soybean, spider mite populations showed three types of seasonal fluctuation, characterized by one peak (August), two peaks (August, November), and three peaks (June, August, October), respectively. On this plant, eight species were found, T. pueraricola being dominant in 1999 (54.7%), T. parakanzawai Ehara in 2000 (72.6%) and T. kanzawai Kishida in 2001 (69.2%). Such annual variation in dominance was probably determined by the order of invasion of soybean fields.

<p class="Body">Prey preference, reproductive performance, and life table of Amblyseius tsugawai (Acari: Phytoseiidae) feeding on Tetranychus urticae and Bemisia tabaci

“…Surveys conducted in orchards and woody plants always showed low densities of A. tsugawai (Kishimoto 2002;Toyoshima 2003;Toyoshima and Amano 2006;Toyoshima et al 2008;Sonoda et al 2012;Wari et al 2014;Ishii et al 2018). In contrast, A. tsugawai appeared to be a dominant species in soybean and other beans (Gotoh et al 2007;Gotoh & Mori 2011). Funayama & Sonoda (2014) reported higher densities of A. tsugawai on Plantago asiatica L. in apple orchards than on apple trees.…”

“…Amblyseius tsugawai Ehara (Acarina: Phytoseiidae) was first described from specimens collected on apples in Japan in 1959 (Ehara 1959). Subsequently, it has been reported from multiple surveys in orchards and vegetables in Japan (Kishimoto 2002;Toyoshima 2003;Toyoshima & Amano 2006;Gotoh et al 2007;Gotoh & Mori 2011;Toyoshima et al 2008;Sonoda et al 2012;Funayama & Sonoda 2014;Wari et al 2014;Funayama et al 2015;Ishii et al 2018), China (Wu 1987;Xia et al 2002) and Korea (Ryu 2007).…”