Study on population fluctuations of Dubas bug, Ommatissus lybicus (Hem: Tropiduchidae) in Iran

Dubas bug (DB), Ommatissus lybicus Bergevin, is one of the key pests of date palm in Iran. The biology and seasonal fluctuations in population of DB in different ecological conditions were studied. Completely infested date palm groves were chosen in Kerman, Bushehr and Khuzestan provinces during 2011-12. Also oviposition behavior of DB and daily activity of nymph were investigated on shoots and the spadix. DB had two generations in three provinces. The emergence of nymphs in winter generation varied from the first half of March in Bushehr to late April in Khuzestan. The emergence of nymphs in summer generation began from late July to early September. Adults were emerged from mid-May in winter generation in three provinces. There was a positive correlation between the population of nymphs and natural enemies include Diptera, Hymenoptera and Coleoptera in both years but no correlation was observed with adult population. DB did not lay eggs on fruits and spadix. Most of the eggs were laid on the upper surface of leaflets in comparison with axis and lower surface at first year 22.07 ± 1.19, 10.24 ± 0.45, 3.45 ± 0.29 and second year 19.35 ± 0.72, 6.28 ± 0.29, 1.71 ± 0.11 respectively. Oviposition was on young leaves (11.12 ± 0.57) more than old leaves (9.29 ± 0.42). Nymphs are hiding during the hottest hours of the day between the bases of the new fronds, palm trunk fiber and on shoots in both generations. DB overwinter in Bushehr province in addition to eggs, nymphs and adults as well.