Observations on biodiversity flora and biological control agents of natural grassland weed.

The observations were made in year 2008 in natural pastures invaded bt Lepidium draba L. – the result of irrational grazing of livestock respectively cows and sheep, from the department of Iassy and department of Vaslui, nort-east of Romania. The pasture flora from the studied plots has 117 species of vascular plants, belonging to 84 genera and 24 families. The most common invasive species are: Lepidium draba, Euphorbia cyparissias, Verbascum phlomoides, Xanthium italicum, etc, wich decrease dramatically the productivity of the ecosystems. Lepidium draba displaces valuable pasture forage species and reduces native biodiversity. In Romania of the most promising biological control agents, the Ceutorhynchus cardariae, the Psylliodes wrasei, and the Aceria drabae. The observations regarding the biological control agents of species Lepidium draba L. is based on visual examination of plants. In the department of Vaslui and Iassy, percent attack of inflorescences by Aceria drabae were contained between 5-35,7% of Vaslui and 14,7-47,5% of Iassy.