Effects of extending the light phase on diapause induction in a Japanese population of the two-spotted spider mite, Tetranychus urticae

Abstract

Artificial lighting is a merit of a 'plant factory', which might be utilized to suppress an increase in pest population. We investigated the effects of extending the light phase on diapause induction in the two-spotted spider mite (TSSM), Tetranychus urticae. TSSM were reared at 18 degrees C under light phases ranging from 2 to 64 h combined with a constant dark phase of 16 h in aluminum bottles, with white light emitting diodes attached inside to minimize fluctuations in air temperature between the light and dark phases. Diapause was induced in adult TSSM females when the light phase was 24 h or shorter, and diapause induction was inhibited when the light phase extended over 32 h. The development of deutonymphs was delayed under a diapause-inducing photoperiod. Diapause inducing photoperiods may suppress an increase in the TSSM population, by slowing down development and reproduction.

Effects of light quality and intensity on diapause induction in the two-spotted spider mite, Tetranychus urticae

“…Experimental devices were made according to Suzuki et al (2007) with some modifications. All experiments were conducted using incubators (MIR-152; SANYO Electric Co. Ltd., Osaka, Japan) equipped with either blue (E1L51-3B; Toyoda Gosei Co. Ltd., Aichi, Japan), green (TLGE183P; Toshiba Co., Tokyo, Japan), orange (TLOE180AP; Toshiba Co.), red (GL5UR3K1; SHARP Co., Osaka, Japan) or white (NSPW500BS; Nichia Co., Tokushima, Japan) LEDs.…”

Scotophase interruption with LEDs and OLEDs to inhibit photoperiodic induction of diapause in Tetranychus urticae and T. kanzawai (Acari: Tetranychidae)

“…Experimental devices LED 'photoperiodic bottles' (300 ml; Suzuki et al 2007Suzuki et al , 2011 and OLED 'photoperiodic boxes' (150 × 125 × 50 mm; Fig. 1) were used to determine photoperiodic curves for diapause induction and conducting scotophase interruption experiments under different light qualities and intensities.…”

“…2A). Air exchange in LED bottles was provided by four 1 cm holes per bottle, and the bottles were covered with a gas-permeable membrane filter (Milliseal; pore diameter = 0.5 mm, Nihon Millipore K.K., Tokyo, Japan) (Suzuki et al 2007(Suzuki et al , 2011. FIGURE 1.…”

“…The two-spotted spider mite, Tetranychus urticae Koch, and the Kanzawa spider mite, T. kanzawai Kishida, are the most common and most serious pest mite species in Japan (Takafuji et al 2000), and they can enter reproductive diapause in response to short photoperiods and/or low temperatures (Veerman 1985;Takafuji et al 2003). Diapause induction in T. urticae and T. kanzawai is sensitive to the photoperiod Article (Parr & Hussey 1966;Veerman 1977Veerman , 2001Gotoh & Shinkaji 1981;Mochizuki & Takafuji 1996;Kroon et al 1997;Morishita & Takafuji 1999;Takafuji & Gotoh 1999;Takafuji et al 2003;Suzuki et al 2007;Suzuki & Takeda 2009;Shah et al 2011a), but only one study has examined the effects of different light colors on diapause induction (Suzuki et al 2008).…”

“…Adult female T. urticae and T. kanzawai enter diapause when exposed to long nights during immature stages, and diapause has been successfully inhibited by either extending the light periods (Suzuki et al 2007) or applying scotophase-interrupting light (Vaz Nunes & Veerman 1984;Suzuki et al 2011;Shah et al 2011b). Scotophase-interrupting experiments on mites have long been conducted to investigate the photoperiodic response of diapause (Lees 1953;Hussey 1972;Shah et al 2011b), but diapause inhibition under different light qualities (colors) and intensities has not been investigated.…”