Occurrence and seasonal fluctuation of Thysanopterοus insects and the mite Eriophyes medicaginis in a new crop of lucerne in Kopais (Central Greece)

The present survey deals with population dynamics, dominancy and frequency of Thysanoptera and the mite Eriophyes medicaginis (Acari: Prostigmata) found in a new crop of lucerne (Medicago sativa) in Kopais (Central Greece) in 2007. A local cultivar (Hiliki) of lucerne was sown there in 2006. Two experimental plots were used, 1000 m2 each. Both were treated as the rest of the crop apart from being sprayed with insecticides. One plot was harvested six times and the other one only four times. Sampling consisted of getting randomly 36 samples of ten shoots of lucerne (approximately 15 cm lenght) once a month from each plot. According to the criteria of dominancy and frequency the species Frankliniella occidentalis (adults) was found to be significant and accidental in both plots, whereas Eriophyes medicaginis was found insignificant and accidental. Larvae of Thysanoptera were dominant and constant in both plots. Adults of Thysanoptera were significant in both plots, but only frequent in the less harvested plot and accidental in the other one. Population peaks of Thysanoptera were recorded in spring and summer, but no insects were found in January and August.