Abstract:
The observations were made in the period 2008 – 2010 in natural pastures from the department of Iassy, nort-east of
Romania. In majority pasture ecosystems exploited by grazing, it is happening a transformation of flora composition,
frequently through adaptation in this surfaces with desirable species (weeds) with low economic value. The researches
were done in the pastures invaded bt Lepidium draba L. – the result of irrational grazing of livestock respectively cows
and horses.
Lepidium draba L. (family Brasicaceae), originary from Europe, became a problem plant in many agricultural
ecosystems from our country. Three of the most promising biological control agents, the gall-forming weevil
Ceutorhynchus cardariae, the flea beetle Psylliodes wrasei, and the gall mite Aceria drabae occur at this site. Attack
by gall mite Aceria drabae Nal., of inflorescences by Lepidium draba L., is based on visual examination of plants, were
contained between 15 -47,5% in 2008 and were contained between 18,8 – 43,4% in 2010.
Plant numbers were analysed using repeated measures analysis of variance. The density of L. draba was four to five
times higher in Iasi, presumably because of the long history of stronger grazing pressure on the associated vegetation.
On variant to have beened disturbed (harrowed) and disturbed and cultivated and mixture of grass seeds, significantly
reduced the number of L. draba plants.
