Analysis of the count of populations and harmfulness of phytophages of agrocenoses of grain cereals of the Central ForestSteppe of Ukraine

Abstract

The count of harmful entomofauna, damage to plants by phytophages and the proportion of their colonization of soft wheat (winter and spring) and common barley (spring) in the Central Forest-Steppe of Ukraine in the spring-summer period of 2004–2019 were analyzed. Such specialized pests as: leafhoppers (Macrosteles laevis Ribaut, Psammotettix alienus L., Calligypona striatella Fall.), aphids (Schizaphis graminum (Rondani), Macrosiphum (Sitobion) avenae (F.), Brachycolus (Cuernavaca) noxius Mordv., Rhopalosiphum padi (L.)), grain bugs (Eurygaster integriceps Put., Eurygaster maura L., Eurygaster austriaca Schrank, Aelia acuminata L.), wheat trips (Haplothrips tritici Kurd.), common ground beetle (Zabrus tenebrioides Goeze), аnisoplia austriaca beetle (Anisoplia austriaca Herbst, Anisoplia segetum Herbst), grain flea beetles (Phyllotreta vittula Redt., Chaetocnema hortensis Geoffr., Chaetocnema aridula Gyll.), cereal leaf beetle (Oulema melanopus (L.), Oulema lichenis Voet.), cereal flies (Oscinella frit L., Oscinella pusila Meigen, Mayetiola destructor (Say), Phorbia securis Tiensuu etc.) were the most common in agrocenoses of grain crops in a harmful entomocomplex. Polyphagous insects, namely caterpillars of gnawing scoops (Scotia segetum Schiff., Scotia exclamationis L.), also caused significant damage in cereal crops. It was revealed that a complex of sucking pests is numerous on winter wheat, represented by wheat thrips (Haplothrips tritici Kurd.), Cereal aphids (Macrosiphum (Sitobion) avenae F., Schizaphis graminum Rond.), Grain sawflies (Cephus pygmaeus L., Trachelus tabidus F.), on spring wheat grain flea beetles (Phyllotreta vittula Redt., Chaetocnema aridula Gyll.) and wheat thrips, on spring barley – grain flea beetles and cereal aphids. Under favorable conditions for overwintering, warm, moderately humid weather in spring and dry weather in summer, active colonization and an increase in the number of phytophages led to their exceeding in 2.5–5.7 times of the economic threshold of harmfulness. Under these conditions, the number of grain bugs (Eurygaster integriceps Put., Е. austriacus Schrnk., Е. maura L., Aelia acuminata L., Dolycoris baccarum L.) in some years reached 8– 15 ind./m2 , ground beetles — up to 20 ind./m2, grain beetles — up to 17 ind./m2, cereal aphids — up to 50 ind./plant.