SEASONAL ACTIVITY OF FIORINIA DATE SCALE, FIORINIA PHOENICIS BALACHOWSKY (HEMIPTERA - DIASPIDIDAE) ON DATE PALM AT GIZA GOVERNORATE, EGYPT

The seasonal activity of fiorinia date scale, Fiorinia phoenicis Balachowsky, 1967 (Hemiptera - Diaspididae) was studied for two years (March, 2008 until mid-February, 2010) on date palm at Giza governorate. The obtained results revealed that F. phoenicis has three overlapping generations under field conditions. The 1st generation (early summer generation) peaked in early June and the 2nd generation (late summer generation) peaked around August/September whereas the 3rd generation (autumn generation) peaked in October/November. The shortest generation was the late summer generation (2.5 - 3.0 months) at 27.9 - 28.6ºC and 63.5 - 64.8%R.H.whereas the longest one was autumn generation (4.5 months) at 21.6 - 22.0ºC and 65.9 - 66.3 %R.H. The early summer generation had intermediate duration (4.0 - 4.5 months) at 20.9 - 21.2ºC and 62.5 - 63.0%R.H in the two years, respectively. The population density was varied in the three generations, the autumn generation was the largest one with total population ranged 944.7 - 1016.0 insects/leaflet with mean of 980.4 insects/leaflet followed by late summer generation 829.0 - 1025.7 insects/leaflet with mean of 927.4 insects/leaflet whereas the smallest one was the early summer generation (422.4 - 575.7 insects/leaflet with mean of 499.1 insects/leaflet). The insect population occurred on date palm fronds all the year round and decreased to lower numbers during winter season and this referred to the cold weather. The basal stratum of date palm leaflets received the highest infestation (37.4 - 38.3%) than middle (34.4 - 35.3%) and apical ones (26.4 - 28.2%). On the other hand, the insect activity affected significantly with daily mean temperature and %R.H. in the both years. The combined effect of daily mean temperature and %R.H on nymph and adult populations showed 66.1 - 69% & 48.1 - 49.2% in the 1st generation, 65.4 - 74.0% & 63.8 - 78.4% in the 2nd generation and 60.9 - 77.4% & 48.6 - 63.5% in the 3rd generation in the both years, respectively.