Japanese Journal of Applied Entomology and Zoology (2013) 57, 235-242

Yoshiyuki Honda, Sachiko Shimizu, Shinji Hanada, Atsushi Kasai and Hiroshi Amano (2013)
[The colonization of Tyrophagus similis Volgin (Acari: Acaridae) on soil algae in a spinach greenhouse]
Japanese Journal of Applied Entomology and Zoology 57 (4), 235-242
Abstract: Recently, greenhouse spinach damage by Tyrophagus similis Volgin (Acari: Acaridae) has increased and threatened spinach production. Tyrophagus similis reproduces well on a diet of rape-seed cake and dried yeast, but the mechanisms of outbreaks in agricultural soil are still unknown. We hypothesized that algae in greenhouse soil facilitate the outbreak of T. similis and investigated its colonizing behavior on soil algae. Colonization tests showed that the water content of algae alone could not explain the mite preference for algae. Tyrophagus similis preferred soil algae such as Botrydiopsis species and a granular soil alga known as Protosiphon, whereas it showed a low preference to the thread-shaped Klebsormidium. The mite density was higher in soil with thick algae than without algae. Colonizing behavior of T. similis on soil algae was initiated by high humidity conditions. Algal growth is a common phenomenon in many spinach greenhouses, but mites usually stay in the soil during the daytime due to low air humidity conditions. They rarely appear on the soil or soil algae surfaces. High air humidity (>95% RH) may promote the appearance of mites on soil algae, which often occurs in the morning after an overnight shower. Results of the present study suggested the possible management of mite damage on spinach by regulating soil algae in the greenhouse.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Japanese)
Database assignments for author(s): Hiroshi Amano

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tyrophagus similis	Spinach (Spinacia oleracea)	Japan