ECOLOGICAL STUDIES ON THE OLIVE PSYLLID, EUPHYLLURA STRAMINEA LOGINOVA (HOMOPTERA: PSYLLOIDEA: APHALARIDAE) IN AL-ARISH, NORTH SINAI, EGYPT | ||||
| Egyptian Journal of Agricultural Research | ||||
| Article 14, Volume 79, Issue 1, March 2001, Page 161-178 PDF (5.64 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejar.2001.397361 | ||||
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| Author | ||||
| EL-SAYED A. ELWAN | ||||
| Plant Protection Research Institute, Agricultural Research Centre, Dokki, Giza, Egypt | ||||
| Abstract | ||||
| The olive psyllid, Euphyllura straminea Log. is an economic important insect pest on olive trees in Egypt. The pest causes severe damage to the olive trees and decline the olive yield in Al-Arish, North Sinai. The present work was conducted for two successive years (1997/98 & 1998199) on a heavily infested olive orchard in Al-Arish. The seasonal abundance, the number of generations and effect of certain weather factors on the population dynamics were studied. The obtained results showed that, The pest have five nymphal in-stars before maturity. The 1st instar nymphs appeared through November or by early December and continued until late June and were abundant during March/April in both years. The 2nd instar nymphs appeared by mid- November or December and continued until late June and abundant in April in both years. The 3rd instar nymphs appeared from December! January and continued until mid-July and abundant through April,' whereas the 4th instar nymphs appeared during January and continued until mid-August and abundant through April in both years. The 5th in-star nymphs appeared through January/February and continued until late August and more abundant through April/May in the two years. The adults occurred all the year round, abundant through April and have a reproductive dormancy in summer and autumn. Oviposition started in November, eggs are deposited in the twig buds of olive shoots and the newly twigs of crowded branches, individually or in batches (2- 4 eggs). The pest had one generation a year on olive trees in Al-Arish, North Sinai. The obtained results showed that, the tested weather factors were significant and negative correlation on the nymphal and adult populations in both years, respectively. The exact effect of these factors on populations revealed that, night minimum temperatures (13.3-13.9°C) and maximum temperatures (25.3-26.3°C) were around optimal range for nymphal activity and within optimal range of the adult activity in the investigated years. The mean temperatures (19.3- 20.1 °C) were within optimal range of nymphal activity and around optimal range of adult activity in both years, respectively, whereas the relative humidity (67.6 69.4% R.H.) was above optimal range of nymphal and adult activities in both years, respectively. The combined effect of tested weather factors on nymphal population were highly significant in both years and the amounts of variability were 68.8% and 63.3% for both years, respectively. Whereas, its effect on adult population were highly significant during the 1st year and significant in the 2nd year and the amount of variability were 71.4% and 53.2% for the studied years. | ||||
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