The aim of this study was to determine the impact of certain levels of nitrogen and potassium fertilizations on the population density of Parlatoria blanchardii (Targioni- Tozzetti) infesting seedy Balady date palm leaflets at Esna district, Luxor Governorate during the two years of (2011/2012 and 2011/2013) as follows:
Concerning, the nitrogen fertilizer, the results showed that the statistical analysis of the data revealed significant differences among the three nitrogen fertilization levels, during the two successive years. Generally, significant increase in insect population size was shown in all months with the increase of nitrogen level, during the two years. Date palm trees received 1.8 kg/tree/year of nitrogen fertilizer, harboured significantly the maximum mean population density of this insect (20.3 and 24.7 individuals per leaflet), followed by those received 0.9 kg/tree/year (17.5 and 19.3 individuals per leaflet), during the two years, respectively. However, trees had no nitrogen fertilizer received the lowest mean number of population (14.7 and 16.8 individuals per leaflet) during the two successive years, respectively. Regarding, the potassium fertilizer, the statistical analysis of data resulted highly significant differences among the three potassium fertilization levels, during the two successive years. Results proved that the increase of potassium rate decreased the mean of population density of this insect. The untreated trees (zero kg/tree/year) of potassium fertilizer, recorded the highest infestation reaching (14.8 and 16.88 individuals per leaflet) for two seasons. While, the treatment (3 kg/tree/year) of potassium fertilizer, reported lowest infestation reaching (9.8 and 11.8 individuals per leaflet) during 2011/2012 and 2012/2013 years, respectively. Generally, it could be concluded from the current investigation that the lowest infestation was found on date palm tree treated with zero rate of nitrogen and 3 kg/tree/year of potassium. While, the mean highest infestation was observed under 1.8 kg/tree/year nitrogen and zero rate of potassium.
Finally, this work may add some information to be used in integrated pest management programs for controlling Parlatoria date scale insect, P. blanchardii.