Published in Scientific Papers. Series A. Agronomy, Vol. LXI, Issue 1
Written by Traian MANOLE
The new agricultural reform policy, which involves an upward trend in the organic farming system of medicinal and aromatic plants, but also plant protection program, raises more and more complicated problems. The protection of organically grown medicinal plants varies according to whether or not the interests of farmers are compatible with the need for introducing these plants grown in the production system. For farmers who cultivate large-grain cereal plants, spontaneous species of the genus Rumex are considered weeds and control measures are taken against them. For those who cultivate Rumex species for food or medical purposes, the protection of these crops raises a number of issues. The common denominator of this controversy is, for some, and for others, the possibility of biological control using biological agents represented by insect species of the Curculionidae family. The flora of Romania includes 25 species and 12 subspecies of the genus Rumex; among them only two species, Rumex patientia L. and R. rugosus Campd, are cultivated in small individual farms. Species of the genus Rumex are widely distributed on Romanian territory, although each species has specific life requirements. Corresponding to the species of the genus Rumex and Rheum are insect species that feed on different plant organs and cause varying degrees of attack. Many of these species are part of two genera of the Curculionidae family: Apion and Rhinoncus. Five species belonging to the Apion genus have been reported in Romania's fauna: Apion frumentarium Payk, A. miniatum Germ., A. cruentatum Steph., A. sanguineum DeGeer and A. rubens Steph. Only one, A. miniatum, which is spread throughout the country, could be used in the biological control of spontaneous Rumex species, or may be considered an important pests for cultivated species. Another important pests belong to the Rhinoncus genus, are three of the eight species occurring on Rumex acetosa L., namely Rhinoncus pericarpius L., Rh. castor F. and Rh. bosnicus Schultze, the last one very rare, was not found in the southern investigation areas. To assess the importance of Rh. pericarpius species both as a harmful species and as a biological control agent, the results obtained in the present paper, refer to the growth of the species under laboratory conditions on natural food. The work brings new data on the feeding trophic range, attack model, incubation duration, fecundity of the female and fertility of the eggs, the active duration of the female and the duration of the growth of the larvae, pupae and diapauses, as well as the spread on the Romanian territory.
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