Dynamics of leaf beetles density (Coleoptera, Chrysomelidae) in grain crops agrocoenoses of the Samara Region

The author studied winter and spring wheat (Trticum) development dynamics in the Volga Region left-bank forest-steppe zone during 19742010 in natural conditions and gardens on the Samara Region cereal crops fields, as well as generation cycles of 6 local species of leaf beetles, with 1-year development, 5 of which do a lot of harm to wheat (Oulema melanopus L., Phyllotreta vittula Redt., Chaetocnema aridula Gyll., Chaetocnema hortensis Geoffr., Hispella atra L.) and 1 (Cassida rubiginosa Mll.) is the consumer of a weed plant Cirsium arvense (L.) Scop.). The author also studied leaf beetles density dynamics and their localization on grain crops of different age. The author studied cereal crops agrocoenoses microclimate under different weather conditions, different plants vegetation intensity at different times of the day. The author also studied major stages of beetles harmful species generation and the timing of their implementation. The paper contains an analysis of the extent and timing of different harmfulness of leaf beetles; the economic value of their separate types. The author surveyed the conditions preferred by the pests of wheat as well as the factors depressing their larval stage and considered the cases of beetles and larvae massive aggregations formation and beetles migration into more comfortable areas. The author comes to the conclusion of the extraordinary plasticity and adaptability of the leaf to the microclimatic conditions of the habitat.