Damages produced by the pest insects can be very big, thus care must be taken about some aspects
concerning the incidence in samples, dynamics and evolution of one of the most important insect pests of the
flowers, such as Thysanoptera. Due to the relatively high incidence of Thrips tabaci in the samples collected
from the experimental field of marigold, the species presented a real economic importance. To obtain a high
production and superior quality it was necessary to choose the best moment for treatments by applying in
function of population dynamics of those pests. In case of population dynamics of adults and larva of Thrips
tabaci from the crop of Calendula officinalis L., the maximal values in all local populations taken in study
were in increase in the second decade of June, and reached the maximum level in the third decade of June. It
was followed by an obvious decrease in July - their number started to decrease to the end of the collecting
period, until the second decade of August, thanks to the end of vegetation period of the flowers. In function
of population dynamics, the best time for applying treatments in the crop flowers was during the period
15.06.2011- 26.06.2011
