Deoxidant-induced anoxia as a physical measure for controlling spider mites (Acari: Tetranychidae)

Abstract

Tiny agricultural pests such as spider mites (Acari: Tetranychidae) attached to seedlings grown outdoors often invade greenhouses, thereby triggering pest outbreaks. To solve the problem, we examined whether differences in anoxia tolerance between animals and plants would permit the application of an anoxic environment to control spider mites without the aid of acaricides. Under an anoxic environment created by using a commercial deoxidant at 25 °C, the time for 50 % mortality of eggs, non-diapausing adults (summer form), and diapausing adults (winter form) were 6.1, 5.5, and 23.6 h, respectively, for Tetranychus urticae Koch and 5.4, 3.9, and 23.2 h, respectively, for Tetranychus kanzawai Kishida. With anoxia for 12 h, no eggs and non-diapausing adults survived in either species, whereas most diapausing adults (98 % for T. urticae and 88 % for T. kanzawai) survived. Under this treatment, host Phaseolus vulgaris L. seedlings showed serious physiological disorders in their primary leaves and apical buds, and unusual lateral buds developed in the cotyledon axils. The spider mites acquire anoxia tolerance during diapause, but anoxia can potentially control them during the summer if no negative effects are observed in the treated seedlings.

Twospotted Spider Mites (Tetranychus urticae) on Strawberry (Fragaria × ananassa) Transplants, and the Potential to Eliminate Them with Steam Treatment

“…Results with the temperatures and durations tested against twospotted spider mites were comparable to results in previous studies. In this study, steam killed all adult females and eggs in 2.7 and 1.9 h, respectively, at 48°C, but dipping infested strawberry leaflets in 47.5°C water killed all females and eggs in 20 and 10 min (Gotoh et al, 2013), suggesting more rapid heating of mites in water than air, but not necessarily anoxic conditions (Suzuki et al, 2015), may have accelerated mortality. In this study, leaf discs with twospotted spider mites were contained in loosely covered Petri-dishes, which may have increased mortality times due to slower heating of dish interiors than the steam chamber itself.…”

A vegetable oil–based biopesticide with ovicidal activity against the two‐spotted spider mite, Tetranychus urticae Koch

“…Respiration is essential for T. urticae eggs; they die under anoxic (0% O 2 ) conditions at 25°C for > 8 h [22, 23]. Since two perforation organs penetrate the T. urticae chorion for taking in air [24], it was initially considered that biopesticides would block these organs and suffocate the eggs.…”

A molecular‐genetic understanding of diapause in spider mites: current knowledge and future directions

“…This may explain the increased tolerance of diapausing females with respect to desiccation (Ghazy & Suzuki, ). Moreover, the stigmata on the cuticle close, also limiting transpiration (McEnroe, ), and potentially enable diapausing females to withstand anoxic pest control treatment (Suzuki et al ., ). Khodayari et al .…”