SOME STUDIES ABOUT THE DYNAMICS EVOLUTION OF THE BIRD’S – FOOT TREFOIL THRIPS (ODONTOTHRIPS LOTI HAL.) POPULATION IN THE CONDITIONS OF THE WESTERN PLAIN PUBLISHEDAna-Maria Vîrteiu, Ioana Grozea
The Lotus corniculatus importance as a green crop consists in the fact that it could change the Lucerne and clover from some of the regions less auspicious for the crop. From this point of view, the opinion of many explorers is unanimous, so that the Lotus corniculatus is a leguminouse with the greatest adaptability at both different weather conditions and soil: drought, high humidity, acid or superficial soils, salts or with a low fertility, stubbed fields etc (Potînc, 1963; Varga, 1964; Pop, 1971, 1972; Dragomir, 1981; Winch and MacDonald, 1961, Laskey and Wakefield, 1978; Dionne, 1969, Varga, 1998). The purpose of the paper is the carrying out of some investigations concerning the incidence in samples and the dynamics of Odontothrips loti Hal. populations evolution. In order to carry out the investigations the experimental field was placed at the Didactical Station Timisoara, during the period of time 2008 - 2009. The experiment was placed after the standard method of location of the experiments; every lot had the length of 2 m and a width of 1 m. For identifying all the stages of the larvae ironwork was constructed and every lot was secluded with a catch mull. The distance between the repetitions was 4 m . For the study of the Lotus corniculatus thrips (Odontothrips loti Hal.) dynamics the collecting of the samples took place during 20 days, with a collecting periodicity at every 48 hours. The evolutions of the adult populations and larvae were similar during those two years of observations. In the case of adults a gradual increasing was observed in the first decade of May , followed by their gradual decreasing until the end of the period. In the case of the larvae after a short decreasing, thanks to the climatical conditions, an increasing of the population could observed, having the maximum of the value at the end of the observation period. The evolution of the populations is determined by the temperatures evolution and relative humidity of the air. The best moment for the application of the treatments was before the adult and especially the larvae populations to increase in an obvious way. By reaching these objectives we try to assure an efficient protection of the Lotus corniculatus crop and by this to obtain a seed production of high quality and a large quantity.
dynamics; bird's - foot trefoil; thrips; populations