Species Composition of Ladybird Beetles and their Seasonal Changes in Tea Fields

Abstract

In 2008 and 2009, we investigated the species composition of ladybird beetles and their seasonal changes in tea fields of Shizuoka Prefecture, Japan. The ladybird beetles were detected by three methods: yellow sticky traps in the tea canopy, SE traps on the tea canopy and beating the side of the tea canopy. Five tea fields in our research center and commercial fields were investigated. Pest management at these fields included various pesticide and non-pesticide control measures. Eight species of the ladybird were found; Chilocorus kuwanae Silvestri, Pseudoscymnus hareja (Weise), Hyperaspis japonica (Crotch), Harmonia axyridis (Pallas), Scymnus (Pullus) kawamurai (Ohta), Coccinella septempunctata Linnaeus, Propylea japonica (Thunberg), and Phymatosternus lewisii (Crotch). The dominant species were C. kuwanae, P. hareja and H. japonica. These three species are predators of scales, and the others seem to be predators of aphids. The peaks of C. kuwanae occurrence in 2008 were observed at the end of June, the beginning of August and mid-September. The peaks of P. hareja were observed from the end of August to the beginning of September, and H. japonica's peaks were observed at the beginning of June and mid-July. The number of C. kuwanae captured in the non-pesticide field was more than those in reduced pesticide and conventional control fields and the number of P. hareja captured in the reduced pesticide field was more than those in other fields.