EFFECT OF CULTIVARS, SOME CLIMATIC FACTORS AND PLANT DEVELOPMENTAL STAGES ON THE POPULATION DENSITY OF ONION THRIPS, THRIPS TABACI LIND. ON GARLIC PLANTS IN EGYPT

Abstract

This study was carried out in Beni-Suef district to study theeffect of cultivars, some climatic factors and plant age on thepopulation density of Thrips tabaci Lind. on two recommendedgarlic cultivars, Balady and Chinese throughout two successiveseasons 2006-2007 and 2007-2008.The results revealed that the highest infestation rate of T. tabaciwas recorded on Balady cultivar, as the corresponding mean numberof nymphs and adults were 82.94 and 11.12 individuals / plant in thefirst season and 62.91 & 11.71 individuals / plant in the secondseason, respectively. The lowest mean number of T. tabaci wasrecorded during first period and increased gradually to reach themaximum number during the second period. Positive relationshipswere recorded between the population density of T. tabaci and thedevelopmental stages of plant. The population density of T. tabacinymphs and adults were negatively correlated with maximum andminimum temperatures. On the other hand, the mean of R.H wasaffected positively on the population of T. tabaci in the twoinvestigated years. In the first season, climatic factors were moreeffective on T. tabaci population nymphs and adults, as the CD(Correlation Coefficient of Determination) were 68.55 and 78.97 %for nymphs and adults on Balady cultivar and vies versa in thesecond season.