Diversity of spider mites (Tetranychidae) on ornamental plants in central Kerala.
Purposive sampling surveys were conducted in homestead gardens and ornamental nurseries at different localities of Thrissur and Ernakulam districts during 2017-19 to study the diversity of spider mites associated with ornamental plants. Mite samples collected from rose, adenium, gerbera, marigold, chrysanthemum, balsam, cock's comb, orchid, cassia, cairo morning glory, zinnia, bauhinia, crape jasmine and pinto peanut were maintained as isoline cultures in the laboratory. Male and female specimens from isolines were slide mounted for morphological characterisation and identification. The results revealed eight species belonging to three genera viz., Tetranychus truncatus Ehara, T. okinawanus Ehara, T. urticae Koch, T. fijiensis Hirst, T. neocaledonicus Andre, T. marianae McGregor, Eutetranychus orientalis Klein and Oligonychus biharensis Hirst. The study recorded new hosts for the alien species, T. okinawanus and T. truncatus which suggests the potential of these species to turn invasive in Kerala's ecosystems. The spider mite fauna on rose was more diverse, indicating the need for imposing strict quarantine regulations. The study observed T. marianae as a new record from Kerala.