Phytosanitary condition of buckwheat and harvest loss caused by harmful organisms on southeast of Central-Chernozem zone

In Central-Chernozem zone (CCZ) the buckwheat occupies the significant planted area. The author studied the species composition and the number of harmful species, and also he determined the complex injuriousness of phytosanitary objects on buckwheat planting of the Dikul’ variety. It was established, that phytosanitary conditions in the sowing of this crop on southeast of CCZ are in whole favorable, but complicated by high weeds number. The weeds were presented by 28 species from 13 families and had the high similarity of species composition during the years of investigation. During droughty periods the buckwheat inhibited a development of weed plants more weakly. The perennial weeds, which exceed the annual plants on their injuriousness, are determining the major portion of harvest loss (1.4 centner/ha or 13.8 %). In this case the injuriousness of Sonchus arvensis was considerably greater than Cirsium horridulum and Convolvulus arvensis ones. Amaranthus retroflexus and cereals are revealing the least injury. The other factors (phytophages, diseases, murine rodent) did not demonstrate the practical significance. The estimation of complex injuriousness of phytosanitary objects permits to determine the total amount of harvest loss as 2.4 centner/ha or 23.7 %.