We used the Dpph method to assess in vitro the antiradical activity of extracts from the roots, leaves and fruits of six Rumex L. (dock) species. Data from preliminary screening indicated that all the tested extracts showed antioxidant properties. The degree of antiradical activity depended upon the plant part. Fruit extracts from R. hydrolapathum Huds., R. obtusifolius L. and R. confertus Willd. showed stronger antiradical properties than the other tested material. We also determined tannin content levels in the extracts and their correlation with antioxidant activity.

Terrain and laboratory research were conducted to determine the potential of Gastroidea viridula Deg. (Coleoptera: Chrysomelidae) to control mossy sorrel (Rumex confertus Willd.). In a field study, the dynamicof plant biomass and number of larvae occurring on that plant were investigated. The Pearson’s linear correlation coefficient of biomass increase in time equalled, to r = 0.96. The regression equation showed, that the plant daily growth reached 29 g; and 210 g per week, consequently. In the laboratory, weight of consumed food by larvae, and larval body weight were measured at 20°C. First generation of G. viridula was taken into consideration. Total weight of consumed leaves by all three instars of a single larva, during 50 days of the development amounted to 1.243 g. Also seasonal abundance of larvae was observed. On May 25th the highest observed number of G. viridula larvae per plant ranged from 435 to 469 individuals. This species may be of usefulness in biological control of mossy sorrel.

There is currently a very favorable climate for biological control of pest weeds. Moreover, biological control plays a significant role in the Integrated Plant Protection Management. Traditional methods of weed control, such as cultivation and the use of herbicides are not practical or desirable for some stands of weeds, and biological control has become an attractive strategy for control of pest weeds. Control of Rumex confertus Willd. by natural enemies that reduce its density is the good example of utilizing biological control on the European and worldwide scale. The aim of the conducted studies was to evaluate the dynamic of population of Pegomya nigritarsis Ztt. (Diptera, Anthomyiidae) on Rumex confertus Willd. and to determine the impact of pest's injuries on the growth of a plant.

Biological methods of weed control are alternative to chemical treatments. Biological techniques are used where no possibility for chemical spraying occurs. Rumex confertus Willd. is an example of a plant-eater which is potentially more important than chemical compounds. The objective of the study was to evaluate population dynamics and the development of l-fypera rumicis L. ( Coleoptera, Cucurlionidae) on Rumex confer/us Willd. as well as to determine effects of the injuries on growth of a plant.

Rumex thyrsiflorus Fingerh. is mentioned as a European folk medicinal plant. This species has also been traditionally used as an edible plant in Eastern Europe because of its nutritional value. During the study, qualitative and quantitative sex-related differences of phenolic constituents in methanolic leaf extracts of R. thyrsiflorus were evaluated. The presence of the same substances (nine phenolic acids before, and six phenolic acids after acid hydrolysis, nine flavonoids, and a catechin) was estimated in both female and male specimens, using the HPLC-DAD method. A statistically significant higher content of eleven constituents in female plant extracts (acids: chlorogenic, p-coumaric, cryptochlorogenic, gallic, protocatechuic, neochlorogenic, vanillic; flavonoids: quercitrin, rhamnetin, rutoside; and catechin) was shown. This is the first report concerning the relation between the sex and the content of biologically active phenolic secondary metabolites in leaf extracts of R. thyrsiflorus. Female plants of R. thyrsiflorus could be useful for pharmaceutical purposes as a preferential source of bioactive phenolic acids, flavonoids and especially catechin.