The two-spotted spider mite Tetranychus urticae Koch is a major pest affecting strawberry production in Japan. Because T. urticae can develop resistance to numerous pesticides, chemical control of the mite throughout the strawberry-growing seasons is difficult. For establishing effective integrated pest management（IPM）strategies for T. urticae, several alternative control measures have been studied. As biological controls, the phytoseiid mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus（McGregor）have been successfully used in many areas. Recently, attempts were made to protect and enhance N. californicus against environmental stress using sheltered sachets and alternative foods. Indigenous natural predators of T. urticae have also been used. As a physical control, CO2 fumigation has been used to markedly suppress the spider mite population in strawberry plants. Ultraviolet-B radiation and vapor heat treatment have also been considered as alternative control measures. These IPM strategies can contribute to effectively controlling T. urticae and reducing the use of acaricides. Practical IPM strategies should be developed through the cooperation of farmers, advisers, and researchers.
In this study, we demonstrate that substrate-borne vibrations induced tonic immobility or startle responses in the adults of the sap beetle Phenolia（Lasiodites）picta（MacLeay）. Most of the tonic immobility and startle responses were induced by large accelerations of vibrations with 8.0 and 16.0 m/s2 at frequencies of 60 and 120 Hz. We also observed that tonic immobility and startle responses during walking were affected by three different intervals（1.0, 4.0, and 9.0 s）of pulsed vibrations with 1.0-s durations at 120 Hz and 8.0 m/s2. All intervals of vibrations showed increased numbers of tonic immobility and startle responses, and they showed decreased durations of walking, compared with control stimulus with continuous vibrations and that without vibrations. In addition, long interval of 9.0 s induced highest rate of tonic immobility and startle responses per pulsed vibration among the three intervals. A negative relationship with walking durations was detected in the numbers of tonic immobility and startle responses. These results suggest that short intervals of vibrations decrease the induction of tonic immobility and startle responses due to habituation.
Seasonal occurrences and species composition of Orius spp. in an okra field of Kawasaki City were investigated. It was confirmed that Orius spp. occurred on okra plants in early-summer and remained until early-autumn. Their peak occurrence advanced with an earlier flowering time. The initial occurrence was not, however, associated with the seasonal prevalence of thrips on okra plants. These results suggest that the main factors influencing the occurrence of Orius spp. in okra fields are prey-independent. The dominant species were O. sauteri（Poppius）and O. minutus（L.）, and their compositions fluctuated between early-summer and early-autumn. Further basic research is required to evaluate okra in order to develop conservation biological control systems for urban agriculture.