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 the effect of cultivars, some climatic factors and plant age on the population density of Thrips tabaci Lind. on two recommended garlic cultivars, Balady and Chinese throughout two successive seasons 2006-2007 and 2007-2008. The results revealed that the highest infestation rate of T. tabaci was recorded on Balady cultivar, as the corresponding mean number of nymphs and adults were 82.94 and 11.12 individuals / plant in the first season and 62.91 & 11.71 individuals / plant in the second season, respectively. The lowest mean number of T. tabaci was recorded during first period and increased gradually to reach the maximum number during the second period. Positive relationships were recorded between the population density of T. tabaci and the developmental stages of plant. The population density of T. tabaci nymphs and adults were negatively correlated with maximum and minimum temperatures. On the other hand, the mean of R.H was affected positively on the population of T. tabaci in the two investigated years. In the first season, climatic factors were more effective 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 the second season.